tkalkirill commented on code in PR #13080:
URL: https://github.com/apache/ignite/pull/13080#discussion_r3155508276


##########
modules/core/src/test/java/org/apache/ignite/internal/processors/cache/transactions/TxSavepointPessimisticTest.java:
##########
@@ -0,0 +1,136 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.internal.processors.cache.transactions;
+
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.IgniteCheckedException;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.configuration.IgniteConfiguration;
+import org.apache.ignite.testframework.GridTestUtils;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+import org.apache.ignite.transactions.Transaction;
+import org.junit.Test;
+
+import static org.apache.ignite.transactions.TransactionConcurrency.OPTIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionConcurrency.PESSIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionIsolation.READ_COMMITTED;
+import static 
org.apache.ignite.transactions.TransactionIsolation.REPEATABLE_READ;
+
+/**
+ * Tests transaction savepoint functionality.
+ * Currently, savepoint API is supported only for pessimistic transactions.
+ */
+public class TxSavepointPessimisticTest extends GridCommonAbstractTest {
+    /** {@inheritDoc} */
+    @Override protected IgniteConfiguration getConfiguration(String 
igniteInstanceName) throws Exception {
+        IgniteConfiguration cfg = super.getConfiguration(igniteInstanceName)
+            .setCacheConfiguration(new CacheConfiguration<>(DEFAULT_CACHE_NAME)
+                .setAtomicityMode(CacheAtomicityMode.TRANSACTIONAL)
+                .setBackups(1)
+                .setCacheMode(CacheMode.PARTITIONED));
+
+        return cfg;
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTest() throws Exception {

Review Comment:
   The same `beforeTest` method is missing.



##########
modules/core/src/test/java/org/apache/ignite/internal/processors/cache/transactions/TxSavepointPessimisticTest.java:
##########
@@ -0,0 +1,136 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.internal.processors.cache.transactions;
+
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.IgniteCheckedException;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.configuration.IgniteConfiguration;
+import org.apache.ignite.testframework.GridTestUtils;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+import org.apache.ignite.transactions.Transaction;
+import org.junit.Test;
+
+import static org.apache.ignite.transactions.TransactionConcurrency.OPTIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionConcurrency.PESSIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionIsolation.READ_COMMITTED;
+import static 
org.apache.ignite.transactions.TransactionIsolation.REPEATABLE_READ;
+
+/**
+ * Tests transaction savepoint functionality.
+ * Currently, savepoint API is supported only for pessimistic transactions.
+ */
+public class TxSavepointPessimisticTest extends GridCommonAbstractTest {
+    /** {@inheritDoc} */
+    @Override protected IgniteConfiguration getConfiguration(String 
igniteInstanceName) throws Exception {
+        IgniteConfiguration cfg = super.getConfiguration(igniteInstanceName)
+            .setCacheConfiguration(new CacheConfiguration<>(DEFAULT_CACHE_NAME)
+                .setAtomicityMode(CacheAtomicityMode.TRANSACTIONAL)
+                .setBackups(1)
+                .setCacheMode(CacheMode.PARTITIONED));
+
+        return cfg;
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTest() throws Exception {
+        stopAllGrids();
+
+        super.afterTest();
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testSavepointRejectedForOptimisticTx() throws Exception {
+        Ignite ignite = startGrid(0);
+
+        try (Transaction tx = ignite.transactions().txStart(OPTIMISTIC, 
REPEATABLE_READ)) {
+            GridTestUtils.assertThrowsAnyCause(log,
+                () -> {
+                    tx.savepoint("sp");
+
+                    return null;
+                },
+                IgniteCheckedException.class,
+                "Savepoints are supported only for PESSIMISTIC transactions.");
+        }
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testSeveralSavepoints() throws Exception {

Review Comment:
   ```suggestion
       public void testRollabackSeveralSavepoints() throws Exception {
   ```



##########
modules/core/src/test/java/org/apache/ignite/internal/processors/cache/transactions/TxSavepointPessimisticTest.java:
##########
@@ -0,0 +1,136 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.internal.processors.cache.transactions;
+
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.IgniteCheckedException;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.configuration.IgniteConfiguration;
+import org.apache.ignite.testframework.GridTestUtils;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+import org.apache.ignite.transactions.Transaction;
+import org.junit.Test;
+
+import static org.apache.ignite.transactions.TransactionConcurrency.OPTIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionConcurrency.PESSIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionIsolation.READ_COMMITTED;
+import static 
org.apache.ignite.transactions.TransactionIsolation.REPEATABLE_READ;
+
+/**
+ * Tests transaction savepoint functionality.
+ * Currently, savepoint API is supported only for pessimistic transactions.
+ */
+public class TxSavepointPessimisticTest extends GridCommonAbstractTest {
+    /** {@inheritDoc} */
+    @Override protected IgniteConfiguration getConfiguration(String 
igniteInstanceName) throws Exception {
+        IgniteConfiguration cfg = super.getConfiguration(igniteInstanceName)
+            .setCacheConfiguration(new CacheConfiguration<>(DEFAULT_CACHE_NAME)
+                .setAtomicityMode(CacheAtomicityMode.TRANSACTIONAL)
+                .setBackups(1)
+                .setCacheMode(CacheMode.PARTITIONED));
+
+        return cfg;
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTest() throws Exception {
+        stopAllGrids();
+
+        super.afterTest();
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testSavepointRejectedForOptimisticTx() throws Exception {
+        Ignite ignite = startGrid(0);

Review Comment:
   Maybe create one node for all tests?



##########
modules/core/src/test/java/org/apache/ignite/internal/processors/cache/transactions/TxSavepointPessimisticTest.java:
##########
@@ -0,0 +1,136 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.internal.processors.cache.transactions;
+
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.IgniteCheckedException;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.configuration.IgniteConfiguration;
+import org.apache.ignite.testframework.GridTestUtils;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+import org.apache.ignite.transactions.Transaction;
+import org.junit.Test;
+
+import static org.apache.ignite.transactions.TransactionConcurrency.OPTIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionConcurrency.PESSIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionIsolation.READ_COMMITTED;
+import static 
org.apache.ignite.transactions.TransactionIsolation.REPEATABLE_READ;
+
+/**
+ * Tests transaction savepoint functionality.
+ * Currently, savepoint API is supported only for pessimistic transactions.
+ */
+public class TxSavepointPessimisticTest extends GridCommonAbstractTest {

Review Comment:
   There is not test with release with multiple savepoints.



##########
modules/core/src/main/java/org/apache/ignite/transactions/Transaction.java:
##########
@@ -290,6 +290,57 @@ public interface Transaction extends AutoCloseable, 
IgniteAsyncSupport {
      */
     public void suspend() throws IgniteException;
 
+    /**
+     * Creates a savepoint in the current transaction.
+     * <p>
+     * Savepoints are supported only for explicit transactions with
+     * {@link TransactionConcurrency#PESSIMISTIC} concurrency. The savepoint 
keeps the current transaction state and can
+     * later be used by {@link #rollbackToSavepoint(String)} to discard 
changes made after it was created.
+     *
+     * @param name Savepoint name.
+     * @throws TransactionException If savepoint with the same name already 
exists.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void savepoint(String name);
+
+    /**
+     * Creates a savepoint in the current transaction.
+     * <p>
+     * Savepoints are supported only for explicit transactions with
+     * {@link TransactionConcurrency#PESSIMISTIC} concurrency. If {@code 
overwrite} is {@code true} and a savepoint with
+     * the same name exists, the existing savepoint is replaced with a 
snapshot of the current transaction state.
+     *
+     * @param name Savepoint name.
+     * @param overwrite Whether to overwrite an existing savepoint with the 
same name.
+     * @throws TransactionException If savepoint with the same name already 
exists and {@code overwrite} is
+     *      {@code false}.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void savepoint(String name, boolean overwrite);
+
+    /**
+     * Rolls back transaction changes to the specified savepoint.
+     * <p>
+     * Changes made after the savepoint was created are discarded. Savepoints 
created after the specified savepoint are
+     * released. The transaction remains active and can be committed or rolled 
back after this method returns.
+     *
+     * @param name Savepoint name.
+     * @throws TransactionException If savepoint with the given name does not 
exist.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void rollbackToSavepoint(String name);

Review Comment:
   I think it's worth adding `@IgniteExperimental`, the api doesn't seem 
finished yet.



##########
modules/core/src/test/java/org/apache/ignite/internal/processors/cache/transactions/TxSavepointParameterizedTest.java:
##########
@@ -0,0 +1,711 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.internal.processors.cache.transactions;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.cache.CacheWriteSynchronizationMode;
+import org.apache.ignite.cluster.ClusterNode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.configuration.NearCacheConfiguration;
+import org.apache.ignite.internal.IgniteInternalFuture;
+import org.apache.ignite.internal.IgniteKernal;
+import org.apache.ignite.internal.processors.cache.GridCacheContext;
+import org.apache.ignite.internal.processors.cache.version.GridCacheVersion;
+import org.apache.ignite.internal.util.typedef.G;
+import org.apache.ignite.testframework.GridTestUtils;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+import org.apache.ignite.transactions.Transaction;
+import org.apache.ignite.transactions.TransactionIsolation;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
+
+import static 
org.apache.ignite.transactions.TransactionConcurrency.PESSIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionIsolation.READ_COMMITTED;
+import static 
org.apache.ignite.transactions.TransactionIsolation.REPEATABLE_READ;
+
+/**
+ * Tests for transaction savepoint API.
+ */
+@RunWith(Parameterized.class)
+public class TxSavepointParameterizedTest extends GridCommonAbstractTest {
+    /** */
+    private static Ignite ignite0;
+
+    /** */
+    private static Ignite ignite1;
+
+    /** */
+    private static Ignite ignite2;
+
+    /** */
+    private static Ignite ignite3;
+
+    /** */
+    private static Ignite client;
+
+    /** */
+    @Parameter(0)
+    public boolean initKeies;
+
+    /** */
+    @Parameter(1)
+    public boolean useNearCache;
+
+    /** */
+    @Parameter(2)
+    public int backups;
+
+    /** */
+    @Parameter(3)
+    public boolean spKeyOnTxInitiator;
+
+    /** */
+    @Parameter(4)
+    public boolean replicated;
+
+    /** */
+    @Parameter(5)
+    public TransactionIsolation transactionIsolation;
+
+    /**
+     * Returns data for test.
+     * @return Test parameters.
+     */
+    @Parameters(name = "initKeies={0}, useNearCache={1}, backups={2}, 
spKeyOnTxInitiator={3}, replicated={4}, txIsolation={5}")
+    public static Collection<Object[]> testData() {
+        return List.of(new Object[][] {
+            // READ_COMMITTED
+            // backups = 0
+            {true, true, 0, true, false, READ_COMMITTED},
+            {true, true, 0, false, false, READ_COMMITTED},
+            {true, false, 0, true, false, READ_COMMITTED},
+            {true, false, 0, false, false, READ_COMMITTED},
+            {false, true, 0, true, false, READ_COMMITTED},
+            {false, true, 0, false, false, READ_COMMITTED},
+            {false, false, 0, true, false, READ_COMMITTED},
+            {false, false, 0, false, false, READ_COMMITTED},
+
+            // backups = 1
+            {true, true, 1, true, false, READ_COMMITTED},
+            {true, true, 1, false, false, READ_COMMITTED},
+            {true, false, 1, true, false, READ_COMMITTED},
+            {true, false, 1, false, false, READ_COMMITTED},
+            {false, true, 1, true, false, READ_COMMITTED},
+            {false, true, 1, false, false, READ_COMMITTED},
+            {false, false, 1, true, false, READ_COMMITTED},
+            {false, false, 1, false, false, READ_COMMITTED},
+
+            // backups = 2
+            {true, true, 2, true, false, READ_COMMITTED},
+            {true, true, 2, false, false, READ_COMMITTED},
+            {true, false, 2, true, false, READ_COMMITTED},
+            {true, false, 2, false, false, READ_COMMITTED},
+            {false, true, 2, true, false, READ_COMMITTED},
+            {false, true, 2, false, false, READ_COMMITTED},
+            {false, false, 2, true, false, READ_COMMITTED},
+            {false, false, 2, false, false, READ_COMMITTED},
+
+            // replicated cache.
+            {true, true, 0, true, true, READ_COMMITTED},
+            {true, false, 0, true, true, READ_COMMITTED},
+            {false, true, 0, true, true, READ_COMMITTED},
+            {false, false, 0, true, true, READ_COMMITTED},
+
+            // REPEATABLE_READ
+            // backups = 0
+            {true, true, 0, true, false, REPEATABLE_READ},
+            {true, true, 0, false, false, REPEATABLE_READ},
+            {true, false, 0, true, false, REPEATABLE_READ},
+            {true, false, 0, false, false, REPEATABLE_READ},
+            {false, true, 0, true, false, REPEATABLE_READ},
+            {false, true, 0, false, false, REPEATABLE_READ},
+            {false, false, 0, true, false, REPEATABLE_READ},
+            {false, false, 0, false, false, REPEATABLE_READ},
+
+            // backups = 1
+            {true, true, 1, true, false, REPEATABLE_READ},
+            {true, true, 1, false, false, REPEATABLE_READ},
+            {true, false, 1, true, false, REPEATABLE_READ},
+            {true, false, 1, false, false, REPEATABLE_READ},
+            {false, true, 1, true, false, REPEATABLE_READ},
+            {false, true, 1, false, false, REPEATABLE_READ},
+            {false, false, 1, true, false, REPEATABLE_READ},
+            {false, false, 1, false, false, REPEATABLE_READ},
+
+            // backups = 2
+            {true, true, 2, true, false, REPEATABLE_READ},
+            {true, true, 2, false, false, REPEATABLE_READ},
+            {true, false, 2, true, false, REPEATABLE_READ},
+            {true, false, 2, false, false, REPEATABLE_READ},
+            {false, true, 2, true, false, REPEATABLE_READ},
+            {false, true, 2, false, false, REPEATABLE_READ},
+            {false, false, 2, true, false, REPEATABLE_READ},
+            {false, false, 2, false, false, REPEATABLE_READ},
+
+            // replicated cache.
+            {true, true, 0, true, true, REPEATABLE_READ},
+            {true, false, 0, true, true, REPEATABLE_READ},
+            {false, true, 0, true, true, REPEATABLE_READ},
+            {false, false, 0, true, true, REPEATABLE_READ},
+        });
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void beforeTestsStarted() throws Exception {
+        super.beforeTestsStarted();
+
+        ignite0 = startGrid(0);
+        ignite1 = startGrid(1);
+        ignite2 = startGrid(2);
+        ignite3 = startGrid(3);
+        client = startClientGrid();
+
+        awaitPartitionMapExchange();
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTestsStopped() throws Exception {
+        stopAllGrids();
+
+        super.afterTestsStopped();
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTest() throws Exception {
+        ignite0.destroyCache(DEFAULT_CACHE_NAME);
+
+        super.afterTest();
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testRollbackToSavepointReleasesRemoteDhtLockAcquireAgain() 
throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int node0Key = primaryKey(cache0);
+        int node1Key = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(node0Key, -1);
+            cache0.put(node1Key, -1);
+        }
+
+        CountDownLatch savepointRolledBackLatch = new CountDownLatch(1);
+        CountDownLatch finishFirstTxLatch = new CountDownLatch(1);
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 2)) {
+                cache0.put(node0Key, 1);
+
+                tx.savepoint("sp");
+
+                cache0.put(node1Key, 1);
+
+                tx.rollbackToSavepoint("sp");
+
+                savepointRolledBackLatch.countDown();
+
+                assertTrue(finishFirstTxLatch.await(10, TimeUnit.SECONDS));
+
+                cache0.put(node1Key, 2);
+
+                tx.commit();
+            }
+        });
+
+        ableToUpdate(node1Key);
+
+        assertFalse(fut.isDone());
+
+        // TODO: IGNITE-28612 Entry visibility violation in transactional 
replication cache with one backup and near.
+        if (initKeies && useNearCache && backups == 1 && spKeyOnTxInitiator && 
!replicated)
+            GridTestUtils.waitForCondition(() -> 
Integer.valueOf(42).equals(cache0.get(node1Key)), 10_000);
+
+        assertEquals(Integer.valueOf(42), cache0.get(node1Key));
+
+        finishFirstTxLatch.countDown();
+
+        fut.get(10_000);
+
+        assertEquals(Integer.valueOf(2), cache0.get(node1Key));
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testOverwriteAndReleaseSavepoint() throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int key = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(key, -1);
+        }
+
+        try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 1)) {
+            cache0.put(key, 1);
+
+            tx.savepoint("sp");
+
+            cache0.put(key, 2);
+
+            tx.savepoint("sp", true);
+
+            cache0.put(key, 3);
+
+            tx.rollbackToSavepoint("sp");
+
+            tx.commit();
+        }
+
+        assertEquals(Integer.valueOf(2), cache0.get(key));
+
+        try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 1)) {
+            tx.savepoint("sp");
+
+            tx.releaseSavepoint("sp");
+
+            GridTestUtils.assertThrowsAnyCause(log,
+                () -> {
+                    tx.rollbackToSavepoint("sp");
+
+                    return null;
+                },
+                IllegalArgumentException.class,
+                "No such savepoint");
+        }
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testRollbackToSavepointReleasesLockForPutRemoveEntry() throws 
Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int key = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(key, -1);
+        }
+
+        CountDownLatch savepointRolledBackLatch = new CountDownLatch(1);
+        CountDownLatch finishFirstTxLatch = new CountDownLatch(1);
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 1)) {
+                tx.savepoint("sp");
+
+                cache0.put(key, 1);
+                cache0.remove(key);
+
+                tx.rollbackToSavepoint("sp");
+
+                savepointRolledBackLatch.countDown();
+
+                assertTrue(finishFirstTxLatch.await(10, TimeUnit.SECONDS));
+
+                tx.commit();
+            }
+        });
+
+        assertTrue(savepointRolledBackLatch.await(10, TimeUnit.SECONDS));
+
+        ableToUpdate(key);
+
+        finishFirstTxLatch.countDown();
+
+        fut.get(10_000);
+
+        assertEquals(Integer.valueOf(42), cache0.get(key));
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testRollbackToSavepoint() {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int key1 = keyForPrimaryAndBackup(ignite0, ignite1);
+        int key2 = keyForPrimaryAndBackup(ignite0, ignite2);
+        int key3 = keyForPrimaryAndBackup(ignite0, ignite3);
+
+        if (initKeies) {
+            cache0.put(key1, -1);
+            cache0.put(key2, -1);
+            cache0.put(key3, -1);
+        }
+
+        try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 3)) {
+            cache0.put(key1, 1);
+
+            tx.savepoint("sp");
+
+            cache0.put(key2, 2);
+
+            tx.rollbackToSavepoint("sp");
+
+            cache0.put(key3, 3);
+
+            tx.commit();
+        }
+
+        assertEquals(Integer.valueOf(1), cache0.get(key1));
+
+        if (initKeies)
+            assertEquals(Integer.valueOf(-1), cache0.get(key2));
+        else
+            assertNull(cache0.get(key2));
+
+        assertEquals(Integer.valueOf(3), cache0.get(key3));
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testClientInitiator() throws Exception {
+        // A client node can not be a primary node for any key.
+        if (spKeyOnTxInitiator)
+            return;
+
+        IgniteCache<Integer, Integer> cache = transactionalCache(client);
+
+        int key1 = keyForPrimaryAndBackup(client, ignite0);
+        int key2 = keyForPrimaryAndBackup(client, ignite1);
+
+        if (initKeies) {
+            cache.put(key1, -1);
+            cache.put(key2, -1);
+        }
+
+        GridCacheVersion[] nearVerRef = new GridCacheVersion[1];
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = client.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 2)) {
+                nearVerRef[0] = ((TransactionProxyImpl<?, 
?>)tx).tx().nearXidVersion();
+
+                Integer val1 = cache.get(key1);
+                Integer val2 = cache.get(key2);
+
+                if (initKeies) {
+                    assertEquals(-1, val1.intValue());
+                    assertEquals(-1, val2.intValue());
+                }
+                else {
+                    assertNull(val1);
+                    assertNull(val2);
+                }
+
+                cache.put(key1, 1);
+                cache.put(key2, 1);
+
+                tx.savepoint("sp");
+
+                cache.put(key1, 2);
+                cache.put(key2, 2);
+
+                tx.rollbackToSavepoint("sp");
+
+                val1 = cache.get(key1);
+                val2 = cache.get(key2);
+
+                assertEquals(1, val1.intValue());
+                assertEquals(1, val2.intValue());
+
+                tx.commit();
+            }
+        });
+
+        fut.get(10_000);
+
+        Integer val1 = cache.get(key1);
+        Integer val2 = cache.get(key2);
+
+        assertEquals(1, val1.intValue());
+        assertEquals(1, val2.intValue());
+
+        assertNoActiveTx(nearVerRef[0]);
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testRollbackAllKey() throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int keyOnInitiator = primaryKey(cache0);
+        int keyOnOtherNode = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(keyOnInitiator, -1);
+            cache0.put(keyOnOtherNode, -1);
+        }
+
+        CountDownLatch rollbackDoneLatch = new CountDownLatch(1);
+        CountDownLatch finishTxLatch = new CountDownLatch(1);
+        GridCacheVersion[] nearVerRef = new GridCacheVersion[1];
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 2)) {
+                nearVerRef[0] = ((TransactionProxyImpl<?, 
?>)tx).tx().nearXidVersion();
+
+                tx.savepoint("sp");
+
+                Integer val1 = cache0.get(keyOnInitiator);
+                Integer val2 = cache0.get(keyOnOtherNode);
+
+                if (initKeies) {
+                    assertEquals(-1, val1.intValue());
+                    assertEquals(-1, val2.intValue());
+                }
+                else {
+                    assertNull(val1);
+                    assertNull(val2);
+                }
+
+                cache0.put(keyOnInitiator, 1);
+                cache0.put(keyOnOtherNode, 1);
+
+                tx.rollbackToSavepoint("sp");
+
+                rollbackDoneLatch.countDown();
+
+                assertTrue(finishTxLatch.await(10, TimeUnit.SECONDS));
+
+                val1 = cache0.get(keyOnInitiator);
+                val2 = cache0.get(keyOnOtherNode);
+
+                assertEquals(42, val1.intValue());
+                assertEquals(42, val2.intValue());
+
+                tx.commit();
+            }
+        });
+
+        assertTrue(rollbackDoneLatch.await(10, TimeUnit.SECONDS));
+
+        assertNoTxStateKeyOnNode(nearVerRef[0], keyOnInitiator);
+        assertNoTxStateKeyOnNode(nearVerRef[0], keyOnOtherNode);
+
+        ableToUpdate(keyOnInitiator);
+        ableToUpdate(keyOnOtherNode);
+
+        finishTxLatch.countDown();
+
+        fut.get(10_000);
+
+        assertNoActiveTx(nearVerRef[0]);
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testDhtEntriesAfterRollbackToSavepoint() throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int keepTxAliveKey = primaryKey(cache0);
+        int dhtKey = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(keepTxAliveKey, -1);
+            cache0.put(dhtKey, -1);
+        }
+
+        CountDownLatch dhtKeyWrittenLatch = new CountDownLatch(1);
+        CountDownLatch proceedRollbackLatch = new CountDownLatch(1);
+        CountDownLatch rollbackDoneLatch = new CountDownLatch(1);
+        CountDownLatch finishTxLatch = new CountDownLatch(1);
+        GridCacheVersion[] nearVerRef = new GridCacheVersion[1];
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 2)) {
+                nearVerRef[0] = ((TransactionProxyImpl<?, 
?>)tx).tx().nearXidVersion();
+
+                cache0.put(keepTxAliveKey, 1);
+
+                tx.savepoint("sp");
+
+                cache0.put(dhtKey, 1);
+
+                dhtKeyWrittenLatch.countDown();
+
+                assertTrue(proceedRollbackLatch.await(10, TimeUnit.SECONDS));
+
+                tx.rollbackToSavepoint("sp");
+
+                rollbackDoneLatch.countDown();
+
+                assertTrue(finishTxLatch.await(10, TimeUnit.SECONDS));
+
+                tx.commit();
+            }
+        });
+
+        assertTrue(dhtKeyWrittenLatch.await(10, TimeUnit.SECONDS));
+        assertNotNull(nearVerRef[0]);
+
+        proceedRollbackLatch.countDown();
+
+        assertTrue(rollbackDoneLatch.await(10, TimeUnit.SECONDS));
+
+        assertNoTxStateKeyOnNode(nearVerRef[0], dhtKey);
+
+        finishTxLatch.countDown();
+
+        fut.get(10_000);
+
+        assertNoActiveTx(nearVerRef[0]);
+    }
+
+    /**
+     * Checks that a key is able to be updated.
+     *
+     * @param key Key to update.
+     * @throws Exception If failed.
+     */
+    private void ableToUpdate(int key) {

Review Comment:
   The method seems odd. The description says it checks, but it actually 
updates, and the title seems to imply the question.
   Please correct the name and description.



##########
modules/core/src/main/java/org/apache/ignite/transactions/Transaction.java:
##########
@@ -290,6 +290,57 @@ public interface Transaction extends AutoCloseable, 
IgniteAsyncSupport {
      */
     public void suspend() throws IgniteException;
 
+    /**
+     * Creates a savepoint in the current transaction.
+     * <p>
+     * Savepoints are supported only for explicit transactions with
+     * {@link TransactionConcurrency#PESSIMISTIC} concurrency. The savepoint 
keeps the current transaction state and can
+     * later be used by {@link #rollbackToSavepoint(String)} to discard 
changes made after it was created.
+     *
+     * @param name Savepoint name.
+     * @throws TransactionException If savepoint with the same name already 
exists.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void savepoint(String name);
+
+    /**
+     * Creates a savepoint in the current transaction.
+     * <p>
+     * Savepoints are supported only for explicit transactions with
+     * {@link TransactionConcurrency#PESSIMISTIC} concurrency. If {@code 
overwrite} is {@code true} and a savepoint with
+     * the same name exists, the existing savepoint is replaced with a 
snapshot of the current transaction state.
+     *
+     * @param name Savepoint name.
+     * @param overwrite Whether to overwrite an existing savepoint with the 
same name.
+     * @throws TransactionException If savepoint with the same name already 
exists and {@code overwrite} is
+     *      {@code false}.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void savepoint(String name, boolean overwrite);

Review Comment:
   I think it's worth adding `@IgniteExperimental`, the api doesn't seem 
finished yet.



##########
modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/GridNearUnlockRequest.java:
##########
@@ -36,6 +36,10 @@ public class GridNearUnlockRequest extends 
GridDistributedBaseMessage {
     @Order(0)
     public List<KeyCacheObject> keys;
 
+    /** Savepoint rollback flag. */
+    @Order(1)
+    public boolean forSavepoint;

Review Comment:
   Check `Rolling Upgrade check` suggests there might be a problem. Let's 
figure out what might be wrong with the feature authors.



##########
modules/core/src/test/java/org/apache/ignite/internal/processors/cache/transactions/TxSavepointPessimisticTest.java:
##########
@@ -0,0 +1,136 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.internal.processors.cache.transactions;
+
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.IgniteCheckedException;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.configuration.IgniteConfiguration;
+import org.apache.ignite.testframework.GridTestUtils;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+import org.apache.ignite.transactions.Transaction;
+import org.junit.Test;
+
+import static org.apache.ignite.transactions.TransactionConcurrency.OPTIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionConcurrency.PESSIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionIsolation.READ_COMMITTED;
+import static 
org.apache.ignite.transactions.TransactionIsolation.REPEATABLE_READ;
+
+/**
+ * Tests transaction savepoint functionality.
+ * Currently, savepoint API is supported only for pessimistic transactions.
+ */
+public class TxSavepointPessimisticTest extends GridCommonAbstractTest {
+    /** {@inheritDoc} */
+    @Override protected IgniteConfiguration getConfiguration(String 
igniteInstanceName) throws Exception {
+        IgniteConfiguration cfg = super.getConfiguration(igniteInstanceName)
+            .setCacheConfiguration(new CacheConfiguration<>(DEFAULT_CACHE_NAME)
+                .setAtomicityMode(CacheAtomicityMode.TRANSACTIONAL)
+                .setBackups(1)
+                .setCacheMode(CacheMode.PARTITIONED));
+
+        return cfg;
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTest() throws Exception {
+        stopAllGrids();
+
+        super.afterTest();
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testSavepointRejectedForOptimisticTx() throws Exception {
+        Ignite ignite = startGrid(0);
+
+        try (Transaction tx = ignite.transactions().txStart(OPTIMISTIC, 
REPEATABLE_READ)) {
+            GridTestUtils.assertThrowsAnyCause(log,
+                () -> {
+                    tx.savepoint("sp");
+
+                    return null;
+                },
+                IgniteCheckedException.class,
+                "Savepoints are supported only for PESSIMISTIC transactions.");
+        }
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testSeveralSavepoints() throws Exception {
+        Ignite ignite = startGrid(0);
+        IgniteCache<Integer, Integer> cache = ignite.cache(DEFAULT_CACHE_NAME);
+
+        int key = 1;
+
+        try (Transaction tx = ignite.transactions().txStart(PESSIMISTIC, 
READ_COMMITTED)) {
+            cache.put(key, 1);
+
+            tx.savepoint("sp1");
+
+            cache.put(key, 2);
+
+            tx.savepoint("sp2");
+
+            cache.put(key, 3);
+
+            tx.savepoint("sp3");
+
+            cache.put(key, 4);
+
+            tx.rollbackToSavepoint("sp1");
+
+            tx.commit();
+        }
+
+        assertEquals(Integer.valueOf(1), cache.get(key));

Review Comment:
   ```suggestion
           assertEquals(1, cache.get(key));
   ```



##########
modules/core/src/test/java/org/apache/ignite/internal/processors/cache/transactions/TxSavepointParameterizedTest.java:
##########
@@ -0,0 +1,711 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.internal.processors.cache.transactions;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.cache.CacheWriteSynchronizationMode;
+import org.apache.ignite.cluster.ClusterNode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.configuration.NearCacheConfiguration;
+import org.apache.ignite.internal.IgniteInternalFuture;
+import org.apache.ignite.internal.IgniteKernal;
+import org.apache.ignite.internal.processors.cache.GridCacheContext;
+import org.apache.ignite.internal.processors.cache.version.GridCacheVersion;
+import org.apache.ignite.internal.util.typedef.G;
+import org.apache.ignite.testframework.GridTestUtils;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+import org.apache.ignite.transactions.Transaction;
+import org.apache.ignite.transactions.TransactionIsolation;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
+
+import static 
org.apache.ignite.transactions.TransactionConcurrency.PESSIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionIsolation.READ_COMMITTED;
+import static 
org.apache.ignite.transactions.TransactionIsolation.REPEATABLE_READ;
+
+/**
+ * Tests for transaction savepoint API.
+ */
+@RunWith(Parameterized.class)
+public class TxSavepointParameterizedTest extends GridCommonAbstractTest {
+    /** */
+    private static Ignite ignite0;
+
+    /** */
+    private static Ignite ignite1;
+
+    /** */
+    private static Ignite ignite2;
+
+    /** */
+    private static Ignite ignite3;
+
+    /** */
+    private static Ignite client;
+
+    /** */
+    @Parameter(0)
+    public boolean initKeies;
+
+    /** */
+    @Parameter(1)
+    public boolean useNearCache;
+
+    /** */
+    @Parameter(2)
+    public int backups;
+
+    /** */
+    @Parameter(3)
+    public boolean spKeyOnTxInitiator;
+
+    /** */
+    @Parameter(4)
+    public boolean replicated;
+
+    /** */
+    @Parameter(5)
+    public TransactionIsolation transactionIsolation;
+
+    /**
+     * Returns data for test.
+     * @return Test parameters.
+     */
+    @Parameters(name = "initKeies={0}, useNearCache={1}, backups={2}, 
spKeyOnTxInitiator={3}, replicated={4}, txIsolation={5}")
+    public static Collection<Object[]> testData() {
+        return List.of(new Object[][] {
+            // READ_COMMITTED
+            // backups = 0
+            {true, true, 0, true, false, READ_COMMITTED},
+            {true, true, 0, false, false, READ_COMMITTED},
+            {true, false, 0, true, false, READ_COMMITTED},
+            {true, false, 0, false, false, READ_COMMITTED},
+            {false, true, 0, true, false, READ_COMMITTED},
+            {false, true, 0, false, false, READ_COMMITTED},
+            {false, false, 0, true, false, READ_COMMITTED},
+            {false, false, 0, false, false, READ_COMMITTED},
+
+            // backups = 1
+            {true, true, 1, true, false, READ_COMMITTED},
+            {true, true, 1, false, false, READ_COMMITTED},
+            {true, false, 1, true, false, READ_COMMITTED},
+            {true, false, 1, false, false, READ_COMMITTED},
+            {false, true, 1, true, false, READ_COMMITTED},
+            {false, true, 1, false, false, READ_COMMITTED},
+            {false, false, 1, true, false, READ_COMMITTED},
+            {false, false, 1, false, false, READ_COMMITTED},
+
+            // backups = 2
+            {true, true, 2, true, false, READ_COMMITTED},
+            {true, true, 2, false, false, READ_COMMITTED},
+            {true, false, 2, true, false, READ_COMMITTED},
+            {true, false, 2, false, false, READ_COMMITTED},
+            {false, true, 2, true, false, READ_COMMITTED},
+            {false, true, 2, false, false, READ_COMMITTED},
+            {false, false, 2, true, false, READ_COMMITTED},
+            {false, false, 2, false, false, READ_COMMITTED},
+
+            // replicated cache.
+            {true, true, 0, true, true, READ_COMMITTED},
+            {true, false, 0, true, true, READ_COMMITTED},
+            {false, true, 0, true, true, READ_COMMITTED},
+            {false, false, 0, true, true, READ_COMMITTED},
+
+            // REPEATABLE_READ
+            // backups = 0
+            {true, true, 0, true, false, REPEATABLE_READ},
+            {true, true, 0, false, false, REPEATABLE_READ},
+            {true, false, 0, true, false, REPEATABLE_READ},
+            {true, false, 0, false, false, REPEATABLE_READ},
+            {false, true, 0, true, false, REPEATABLE_READ},
+            {false, true, 0, false, false, REPEATABLE_READ},
+            {false, false, 0, true, false, REPEATABLE_READ},
+            {false, false, 0, false, false, REPEATABLE_READ},
+
+            // backups = 1
+            {true, true, 1, true, false, REPEATABLE_READ},
+            {true, true, 1, false, false, REPEATABLE_READ},
+            {true, false, 1, true, false, REPEATABLE_READ},
+            {true, false, 1, false, false, REPEATABLE_READ},
+            {false, true, 1, true, false, REPEATABLE_READ},
+            {false, true, 1, false, false, REPEATABLE_READ},
+            {false, false, 1, true, false, REPEATABLE_READ},
+            {false, false, 1, false, false, REPEATABLE_READ},
+
+            // backups = 2
+            {true, true, 2, true, false, REPEATABLE_READ},
+            {true, true, 2, false, false, REPEATABLE_READ},
+            {true, false, 2, true, false, REPEATABLE_READ},
+            {true, false, 2, false, false, REPEATABLE_READ},
+            {false, true, 2, true, false, REPEATABLE_READ},
+            {false, true, 2, false, false, REPEATABLE_READ},
+            {false, false, 2, true, false, REPEATABLE_READ},
+            {false, false, 2, false, false, REPEATABLE_READ},
+
+            // replicated cache.
+            {true, true, 0, true, true, REPEATABLE_READ},
+            {true, false, 0, true, true, REPEATABLE_READ},
+            {false, true, 0, true, true, REPEATABLE_READ},
+            {false, false, 0, true, true, REPEATABLE_READ},
+        });
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void beforeTestsStarted() throws Exception {
+        super.beforeTestsStarted();
+
+        ignite0 = startGrid(0);
+        ignite1 = startGrid(1);
+        ignite2 = startGrid(2);
+        ignite3 = startGrid(3);
+        client = startClientGrid();
+
+        awaitPartitionMapExchange();
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTestsStopped() throws Exception {
+        stopAllGrids();
+
+        super.afterTestsStopped();
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTest() throws Exception {
+        ignite0.destroyCache(DEFAULT_CACHE_NAME);
+
+        super.afterTest();
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testRollbackToSavepointReleasesRemoteDhtLockAcquireAgain() 
throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int node0Key = primaryKey(cache0);
+        int node1Key = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(node0Key, -1);
+            cache0.put(node1Key, -1);
+        }
+
+        CountDownLatch savepointRolledBackLatch = new CountDownLatch(1);
+        CountDownLatch finishFirstTxLatch = new CountDownLatch(1);
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 2)) {
+                cache0.put(node0Key, 1);
+
+                tx.savepoint("sp");
+
+                cache0.put(node1Key, 1);
+
+                tx.rollbackToSavepoint("sp");
+
+                savepointRolledBackLatch.countDown();
+
+                assertTrue(finishFirstTxLatch.await(10, TimeUnit.SECONDS));
+
+                cache0.put(node1Key, 2);
+
+                tx.commit();
+            }
+        });
+
+        ableToUpdate(node1Key);
+
+        assertFalse(fut.isDone());
+
+        // TODO: IGNITE-28612 Entry visibility violation in transactional 
replication cache with one backup and near.
+        if (initKeies && useNearCache && backups == 1 && spKeyOnTxInitiator && 
!replicated)
+            GridTestUtils.waitForCondition(() -> 
Integer.valueOf(42).equals(cache0.get(node1Key)), 10_000);
+
+        assertEquals(Integer.valueOf(42), cache0.get(node1Key));
+
+        finishFirstTxLatch.countDown();
+
+        fut.get(10_000);
+
+        assertEquals(Integer.valueOf(2), cache0.get(node1Key));
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testOverwriteAndReleaseSavepoint() throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int key = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(key, -1);
+        }
+
+        try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 1)) {
+            cache0.put(key, 1);
+
+            tx.savepoint("sp");
+
+            cache0.put(key, 2);
+
+            tx.savepoint("sp", true);
+
+            cache0.put(key, 3);
+
+            tx.rollbackToSavepoint("sp");
+
+            tx.commit();
+        }
+
+        assertEquals(Integer.valueOf(2), cache0.get(key));
+
+        try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 1)) {
+            tx.savepoint("sp");
+
+            tx.releaseSavepoint("sp");
+
+            GridTestUtils.assertThrowsAnyCause(log,
+                () -> {
+                    tx.rollbackToSavepoint("sp");
+
+                    return null;
+                },
+                IllegalArgumentException.class,
+                "No such savepoint");
+        }
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testRollbackToSavepointReleasesLockForPutRemoveEntry() throws 
Exception {

Review Comment:
   Can it be combined with 
`testRollbackToSavepointReleasesRemoteDhtLockAcquireAgain`?



##########
modules/core/src/test/java/org/apache/ignite/internal/processors/cache/transactions/TxSavepointParameterizedTest.java:
##########
@@ -0,0 +1,711 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.internal.processors.cache.transactions;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.cache.CacheWriteSynchronizationMode;
+import org.apache.ignite.cluster.ClusterNode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.configuration.NearCacheConfiguration;
+import org.apache.ignite.internal.IgniteInternalFuture;
+import org.apache.ignite.internal.IgniteKernal;
+import org.apache.ignite.internal.processors.cache.GridCacheContext;
+import org.apache.ignite.internal.processors.cache.version.GridCacheVersion;
+import org.apache.ignite.internal.util.typedef.G;
+import org.apache.ignite.testframework.GridTestUtils;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+import org.apache.ignite.transactions.Transaction;
+import org.apache.ignite.transactions.TransactionIsolation;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
+
+import static 
org.apache.ignite.transactions.TransactionConcurrency.PESSIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionIsolation.READ_COMMITTED;
+import static 
org.apache.ignite.transactions.TransactionIsolation.REPEATABLE_READ;
+
+/**
+ * Tests for transaction savepoint API.
+ */
+@RunWith(Parameterized.class)
+public class TxSavepointParameterizedTest extends GridCommonAbstractTest {
+    /** */
+    private static Ignite ignite0;
+
+    /** */
+    private static Ignite ignite1;
+
+    /** */
+    private static Ignite ignite2;
+
+    /** */
+    private static Ignite ignite3;
+
+    /** */
+    private static Ignite client;
+
+    /** */
+    @Parameter(0)
+    public boolean initKeies;
+
+    /** */
+    @Parameter(1)
+    public boolean useNearCache;
+
+    /** */
+    @Parameter(2)
+    public int backups;
+
+    /** */
+    @Parameter(3)
+    public boolean spKeyOnTxInitiator;
+
+    /** */
+    @Parameter(4)
+    public boolean replicated;
+
+    /** */
+    @Parameter(5)
+    public TransactionIsolation transactionIsolation;
+
+    /**
+     * Returns data for test.
+     * @return Test parameters.
+     */
+    @Parameters(name = "initKeies={0}, useNearCache={1}, backups={2}, 
spKeyOnTxInitiator={3}, replicated={4}, txIsolation={5}")
+    public static Collection<Object[]> testData() {
+        return List.of(new Object[][] {
+            // READ_COMMITTED
+            // backups = 0
+            {true, true, 0, true, false, READ_COMMITTED},
+            {true, true, 0, false, false, READ_COMMITTED},
+            {true, false, 0, true, false, READ_COMMITTED},
+            {true, false, 0, false, false, READ_COMMITTED},
+            {false, true, 0, true, false, READ_COMMITTED},
+            {false, true, 0, false, false, READ_COMMITTED},
+            {false, false, 0, true, false, READ_COMMITTED},
+            {false, false, 0, false, false, READ_COMMITTED},
+
+            // backups = 1
+            {true, true, 1, true, false, READ_COMMITTED},
+            {true, true, 1, false, false, READ_COMMITTED},
+            {true, false, 1, true, false, READ_COMMITTED},
+            {true, false, 1, false, false, READ_COMMITTED},
+            {false, true, 1, true, false, READ_COMMITTED},
+            {false, true, 1, false, false, READ_COMMITTED},
+            {false, false, 1, true, false, READ_COMMITTED},
+            {false, false, 1, false, false, READ_COMMITTED},
+
+            // backups = 2
+            {true, true, 2, true, false, READ_COMMITTED},
+            {true, true, 2, false, false, READ_COMMITTED},
+            {true, false, 2, true, false, READ_COMMITTED},
+            {true, false, 2, false, false, READ_COMMITTED},
+            {false, true, 2, true, false, READ_COMMITTED},
+            {false, true, 2, false, false, READ_COMMITTED},
+            {false, false, 2, true, false, READ_COMMITTED},
+            {false, false, 2, false, false, READ_COMMITTED},
+
+            // replicated cache.
+            {true, true, 0, true, true, READ_COMMITTED},
+            {true, false, 0, true, true, READ_COMMITTED},
+            {false, true, 0, true, true, READ_COMMITTED},
+            {false, false, 0, true, true, READ_COMMITTED},
+
+            // REPEATABLE_READ
+            // backups = 0
+            {true, true, 0, true, false, REPEATABLE_READ},
+            {true, true, 0, false, false, REPEATABLE_READ},
+            {true, false, 0, true, false, REPEATABLE_READ},
+            {true, false, 0, false, false, REPEATABLE_READ},
+            {false, true, 0, true, false, REPEATABLE_READ},
+            {false, true, 0, false, false, REPEATABLE_READ},
+            {false, false, 0, true, false, REPEATABLE_READ},
+            {false, false, 0, false, false, REPEATABLE_READ},
+
+            // backups = 1
+            {true, true, 1, true, false, REPEATABLE_READ},
+            {true, true, 1, false, false, REPEATABLE_READ},
+            {true, false, 1, true, false, REPEATABLE_READ},
+            {true, false, 1, false, false, REPEATABLE_READ},
+            {false, true, 1, true, false, REPEATABLE_READ},
+            {false, true, 1, false, false, REPEATABLE_READ},
+            {false, false, 1, true, false, REPEATABLE_READ},
+            {false, false, 1, false, false, REPEATABLE_READ},
+
+            // backups = 2
+            {true, true, 2, true, false, REPEATABLE_READ},
+            {true, true, 2, false, false, REPEATABLE_READ},
+            {true, false, 2, true, false, REPEATABLE_READ},
+            {true, false, 2, false, false, REPEATABLE_READ},
+            {false, true, 2, true, false, REPEATABLE_READ},
+            {false, true, 2, false, false, REPEATABLE_READ},
+            {false, false, 2, true, false, REPEATABLE_READ},
+            {false, false, 2, false, false, REPEATABLE_READ},
+
+            // replicated cache.
+            {true, true, 0, true, true, REPEATABLE_READ},
+            {true, false, 0, true, true, REPEATABLE_READ},
+            {false, true, 0, true, true, REPEATABLE_READ},
+            {false, false, 0, true, true, REPEATABLE_READ},
+        });
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void beforeTestsStarted() throws Exception {
+        super.beforeTestsStarted();
+
+        ignite0 = startGrid(0);
+        ignite1 = startGrid(1);
+        ignite2 = startGrid(2);
+        ignite3 = startGrid(3);
+        client = startClientGrid();
+
+        awaitPartitionMapExchange();
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTestsStopped() throws Exception {
+        stopAllGrids();
+
+        super.afterTestsStopped();
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTest() throws Exception {
+        ignite0.destroyCache(DEFAULT_CACHE_NAME);
+
+        super.afterTest();
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testRollbackToSavepointReleasesRemoteDhtLockAcquireAgain() 
throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int node0Key = primaryKey(cache0);
+        int node1Key = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(node0Key, -1);
+            cache0.put(node1Key, -1);
+        }
+
+        CountDownLatch savepointRolledBackLatch = new CountDownLatch(1);
+        CountDownLatch finishFirstTxLatch = new CountDownLatch(1);
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 2)) {
+                cache0.put(node0Key, 1);
+
+                tx.savepoint("sp");
+
+                cache0.put(node1Key, 1);
+
+                tx.rollbackToSavepoint("sp");
+
+                savepointRolledBackLatch.countDown();
+
+                assertTrue(finishFirstTxLatch.await(10, TimeUnit.SECONDS));
+
+                cache0.put(node1Key, 2);
+
+                tx.commit();
+            }
+        });
+
+        ableToUpdate(node1Key);
+
+        assertFalse(fut.isDone());
+
+        // TODO: IGNITE-28612 Entry visibility violation in transactional 
replication cache with one backup and near.
+        if (initKeies && useNearCache && backups == 1 && spKeyOnTxInitiator && 
!replicated)
+            GridTestUtils.waitForCondition(() -> 
Integer.valueOf(42).equals(cache0.get(node1Key)), 10_000);

Review Comment:
   Why without assertTrue/false(waitForCondition) ?



##########
docs/_docs/code-snippets/java/src/main/java/org/apache/ignite/snippets/PerformingTransactions.java:
##########
@@ -98,6 +99,38 @@ public static void executingTransactionsExample() {
         }
     }
 
+    public static void transactionSavepointsExample() {
+        try (Ignite ignite = Ignition.start()) {
+            // tag::savepoints[]
+            CacheConfiguration<String, Integer> cfg = new 
CacheConfiguration<>();
+            cfg.setAtomicityMode(CacheAtomicityMode.TRANSACTIONAL);
+            cfg.setName("myCache");
+
+            IgniteCache<String, Integer> cache = ignite.getOrCreateCache(cfg);
+
+            try (Transaction tx = 
ignite.transactions().txStart(TransactionConcurrency.PESSIMISTIC,

Review Comment:
   ```suggestion
               CacheConfiguration<String, Integer> cfg = new 
CacheConfiguration<>();
               cfg.setAtomicityMode(CacheAtomicityMode.TRANSACTIONAL);
               cfg.setName("myCache");
   
               IgniteCache<String, Integer> cache = 
ignite.getOrCreateCache(cfg);
   
               // tag::savepoints[]
               try (Transaction tx = 
ignite.transactions().txStart(TransactionConcurrency.PESSIMISTIC,
   ```



##########
docs/_docs/key-value-api/transactions.adoc:
##########
@@ -90,6 +90,34 @@ 
include::code-snippets/cpp/src/transactions.cpp[tag=transactions-execution,inden
 It is critical that an Ignite Transaction should be `closed` regardless of its 
commit state or ocurred exceptions. Using of `try-with-resources` is 
recommended approach, but you can also explicitly call `rollback` when catching 
exceptions. Calling of `close`, `commit` or `rollback` ensures that all 
resources are released and the transaction is no longer bound to the current 
thread.
 ====
 
+== Transaction Savepoints
+
+Savepoints allow you to mark an intermediate state inside an explicit 
transaction and later roll back only the changes made after that point.
+They are useful when a transaction contains several logical steps and one of 
the later steps can be discarded without rolling back the whole transaction.
+
+Ignite supports savepoints only for explicit `PESSIMISTIC` transactions.
+Savepoints are local to the transaction that created them and are removed when 
the transaction is committed or rolled back.
+
+Use `Transaction.savepoint(name)` to create a savepoint.
+If a savepoint with the same name already exists, Ignite throws a 
`TransactionException`.
+Use `Transaction.savepoint(name, true)` to replace an existing savepoint.
+
+Use `Transaction.rollbackToSavepoint(name)` to roll back transaction changes 
made after the savepoint was created.
+Savepoints created after the target savepoint are released as part of this 
operation.

Review Comment:
   maybe not released, but rolled back out?



##########
modules/core/src/test/java/org/apache/ignite/internal/processors/cache/transactions/TxSavepointParameterizedTest.java:
##########
@@ -0,0 +1,711 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.internal.processors.cache.transactions;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.cache.CacheWriteSynchronizationMode;
+import org.apache.ignite.cluster.ClusterNode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.configuration.NearCacheConfiguration;
+import org.apache.ignite.internal.IgniteInternalFuture;
+import org.apache.ignite.internal.IgniteKernal;
+import org.apache.ignite.internal.processors.cache.GridCacheContext;
+import org.apache.ignite.internal.processors.cache.version.GridCacheVersion;
+import org.apache.ignite.internal.util.typedef.G;
+import org.apache.ignite.testframework.GridTestUtils;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+import org.apache.ignite.transactions.Transaction;
+import org.apache.ignite.transactions.TransactionIsolation;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
+
+import static 
org.apache.ignite.transactions.TransactionConcurrency.PESSIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionIsolation.READ_COMMITTED;
+import static 
org.apache.ignite.transactions.TransactionIsolation.REPEATABLE_READ;
+
+/**
+ * Tests for transaction savepoint API.
+ */
+@RunWith(Parameterized.class)
+public class TxSavepointParameterizedTest extends GridCommonAbstractTest {
+    /** */
+    private static Ignite ignite0;
+
+    /** */
+    private static Ignite ignite1;
+
+    /** */
+    private static Ignite ignite2;
+
+    /** */
+    private static Ignite ignite3;
+
+    /** */
+    private static Ignite client;
+
+    /** */
+    @Parameter(0)
+    public boolean initKeies;
+
+    /** */
+    @Parameter(1)
+    public boolean useNearCache;
+
+    /** */
+    @Parameter(2)
+    public int backups;
+
+    /** */
+    @Parameter(3)
+    public boolean spKeyOnTxInitiator;
+
+    /** */
+    @Parameter(4)
+    public boolean replicated;
+
+    /** */
+    @Parameter(5)
+    public TransactionIsolation transactionIsolation;
+
+    /**
+     * Returns data for test.
+     * @return Test parameters.
+     */
+    @Parameters(name = "initKeies={0}, useNearCache={1}, backups={2}, 
spKeyOnTxInitiator={3}, replicated={4}, txIsolation={5}")
+    public static Collection<Object[]> testData() {
+        return List.of(new Object[][] {
+            // READ_COMMITTED
+            // backups = 0
+            {true, true, 0, true, false, READ_COMMITTED},
+            {true, true, 0, false, false, READ_COMMITTED},
+            {true, false, 0, true, false, READ_COMMITTED},
+            {true, false, 0, false, false, READ_COMMITTED},
+            {false, true, 0, true, false, READ_COMMITTED},
+            {false, true, 0, false, false, READ_COMMITTED},
+            {false, false, 0, true, false, READ_COMMITTED},
+            {false, false, 0, false, false, READ_COMMITTED},
+
+            // backups = 1
+            {true, true, 1, true, false, READ_COMMITTED},
+            {true, true, 1, false, false, READ_COMMITTED},
+            {true, false, 1, true, false, READ_COMMITTED},
+            {true, false, 1, false, false, READ_COMMITTED},
+            {false, true, 1, true, false, READ_COMMITTED},
+            {false, true, 1, false, false, READ_COMMITTED},
+            {false, false, 1, true, false, READ_COMMITTED},
+            {false, false, 1, false, false, READ_COMMITTED},
+
+            // backups = 2
+            {true, true, 2, true, false, READ_COMMITTED},
+            {true, true, 2, false, false, READ_COMMITTED},
+            {true, false, 2, true, false, READ_COMMITTED},
+            {true, false, 2, false, false, READ_COMMITTED},
+            {false, true, 2, true, false, READ_COMMITTED},
+            {false, true, 2, false, false, READ_COMMITTED},
+            {false, false, 2, true, false, READ_COMMITTED},
+            {false, false, 2, false, false, READ_COMMITTED},
+
+            // replicated cache.
+            {true, true, 0, true, true, READ_COMMITTED},
+            {true, false, 0, true, true, READ_COMMITTED},
+            {false, true, 0, true, true, READ_COMMITTED},
+            {false, false, 0, true, true, READ_COMMITTED},
+
+            // REPEATABLE_READ
+            // backups = 0
+            {true, true, 0, true, false, REPEATABLE_READ},
+            {true, true, 0, false, false, REPEATABLE_READ},
+            {true, false, 0, true, false, REPEATABLE_READ},
+            {true, false, 0, false, false, REPEATABLE_READ},
+            {false, true, 0, true, false, REPEATABLE_READ},
+            {false, true, 0, false, false, REPEATABLE_READ},
+            {false, false, 0, true, false, REPEATABLE_READ},
+            {false, false, 0, false, false, REPEATABLE_READ},
+
+            // backups = 1
+            {true, true, 1, true, false, REPEATABLE_READ},
+            {true, true, 1, false, false, REPEATABLE_READ},
+            {true, false, 1, true, false, REPEATABLE_READ},
+            {true, false, 1, false, false, REPEATABLE_READ},
+            {false, true, 1, true, false, REPEATABLE_READ},
+            {false, true, 1, false, false, REPEATABLE_READ},
+            {false, false, 1, true, false, REPEATABLE_READ},
+            {false, false, 1, false, false, REPEATABLE_READ},
+
+            // backups = 2
+            {true, true, 2, true, false, REPEATABLE_READ},
+            {true, true, 2, false, false, REPEATABLE_READ},
+            {true, false, 2, true, false, REPEATABLE_READ},
+            {true, false, 2, false, false, REPEATABLE_READ},
+            {false, true, 2, true, false, REPEATABLE_READ},
+            {false, true, 2, false, false, REPEATABLE_READ},
+            {false, false, 2, true, false, REPEATABLE_READ},
+            {false, false, 2, false, false, REPEATABLE_READ},
+
+            // replicated cache.
+            {true, true, 0, true, true, REPEATABLE_READ},
+            {true, false, 0, true, true, REPEATABLE_READ},
+            {false, true, 0, true, true, REPEATABLE_READ},
+            {false, false, 0, true, true, REPEATABLE_READ},
+        });
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void beforeTestsStarted() throws Exception {
+        super.beforeTestsStarted();
+
+        ignite0 = startGrid(0);
+        ignite1 = startGrid(1);
+        ignite2 = startGrid(2);
+        ignite3 = startGrid(3);
+        client = startClientGrid();
+
+        awaitPartitionMapExchange();
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTestsStopped() throws Exception {
+        stopAllGrids();
+
+        super.afterTestsStopped();
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTest() throws Exception {
+        ignite0.destroyCache(DEFAULT_CACHE_NAME);
+
+        super.afterTest();
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testRollbackToSavepointReleasesRemoteDhtLockAcquireAgain() 
throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int node0Key = primaryKey(cache0);
+        int node1Key = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(node0Key, -1);
+            cache0.put(node1Key, -1);
+        }
+
+        CountDownLatch savepointRolledBackLatch = new CountDownLatch(1);
+        CountDownLatch finishFirstTxLatch = new CountDownLatch(1);
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 2)) {
+                cache0.put(node0Key, 1);
+
+                tx.savepoint("sp");
+
+                cache0.put(node1Key, 1);
+
+                tx.rollbackToSavepoint("sp");
+
+                savepointRolledBackLatch.countDown();
+
+                assertTrue(finishFirstTxLatch.await(10, TimeUnit.SECONDS));
+
+                cache0.put(node1Key, 2);
+
+                tx.commit();
+            }
+        });
+
+        ableToUpdate(node1Key);
+
+        assertFalse(fut.isDone());
+
+        // TODO: IGNITE-28612 Entry visibility violation in transactional 
replication cache with one backup and near.
+        if (initKeies && useNearCache && backups == 1 && spKeyOnTxInitiator && 
!replicated)
+            GridTestUtils.waitForCondition(() -> 
Integer.valueOf(42).equals(cache0.get(node1Key)), 10_000);
+
+        assertEquals(Integer.valueOf(42), cache0.get(node1Key));
+
+        finishFirstTxLatch.countDown();
+
+        fut.get(10_000);
+
+        assertEquals(Integer.valueOf(2), cache0.get(node1Key));
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testOverwriteAndReleaseSavepoint() throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int key = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(key, -1);
+        }
+
+        try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 1)) {
+            cache0.put(key, 1);
+
+            tx.savepoint("sp");
+
+            cache0.put(key, 2);
+
+            tx.savepoint("sp", true);
+
+            cache0.put(key, 3);
+
+            tx.rollbackToSavepoint("sp");
+
+            tx.commit();
+        }
+
+        assertEquals(Integer.valueOf(2), cache0.get(key));
+
+        try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 1)) {

Review Comment:
   I suggest putting it into a separate test method.



##########
modules/core/src/test/java/org/apache/ignite/internal/processors/cache/transactions/TxSavepointParameterizedTest.java:
##########
@@ -0,0 +1,711 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.internal.processors.cache.transactions;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.cache.CacheWriteSynchronizationMode;
+import org.apache.ignite.cluster.ClusterNode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.configuration.NearCacheConfiguration;
+import org.apache.ignite.internal.IgniteInternalFuture;
+import org.apache.ignite.internal.IgniteKernal;
+import org.apache.ignite.internal.processors.cache.GridCacheContext;
+import org.apache.ignite.internal.processors.cache.version.GridCacheVersion;
+import org.apache.ignite.internal.util.typedef.G;
+import org.apache.ignite.testframework.GridTestUtils;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+import org.apache.ignite.transactions.Transaction;
+import org.apache.ignite.transactions.TransactionIsolation;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
+
+import static 
org.apache.ignite.transactions.TransactionConcurrency.PESSIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionIsolation.READ_COMMITTED;
+import static 
org.apache.ignite.transactions.TransactionIsolation.REPEATABLE_READ;
+
+/**
+ * Tests for transaction savepoint API.
+ */
+@RunWith(Parameterized.class)
+public class TxSavepointParameterizedTest extends GridCommonAbstractTest {
+    /** */
+    private static Ignite ignite0;
+
+    /** */
+    private static Ignite ignite1;
+
+    /** */
+    private static Ignite ignite2;
+
+    /** */
+    private static Ignite ignite3;
+
+    /** */
+    private static Ignite client;
+
+    /** */
+    @Parameter(0)
+    public boolean initKeies;
+
+    /** */
+    @Parameter(1)
+    public boolean useNearCache;
+
+    /** */
+    @Parameter(2)
+    public int backups;
+
+    /** */
+    @Parameter(3)
+    public boolean spKeyOnTxInitiator;
+
+    /** */
+    @Parameter(4)
+    public boolean replicated;
+
+    /** */
+    @Parameter(5)
+    public TransactionIsolation transactionIsolation;
+
+    /**
+     * Returns data for test.
+     * @return Test parameters.
+     */
+    @Parameters(name = "initKeies={0}, useNearCache={1}, backups={2}, 
spKeyOnTxInitiator={3}, replicated={4}, txIsolation={5}")
+    public static Collection<Object[]> testData() {
+        return List.of(new Object[][] {
+            // READ_COMMITTED
+            // backups = 0
+            {true, true, 0, true, false, READ_COMMITTED},
+            {true, true, 0, false, false, READ_COMMITTED},
+            {true, false, 0, true, false, READ_COMMITTED},
+            {true, false, 0, false, false, READ_COMMITTED},
+            {false, true, 0, true, false, READ_COMMITTED},
+            {false, true, 0, false, false, READ_COMMITTED},
+            {false, false, 0, true, false, READ_COMMITTED},
+            {false, false, 0, false, false, READ_COMMITTED},
+
+            // backups = 1
+            {true, true, 1, true, false, READ_COMMITTED},
+            {true, true, 1, false, false, READ_COMMITTED},
+            {true, false, 1, true, false, READ_COMMITTED},
+            {true, false, 1, false, false, READ_COMMITTED},
+            {false, true, 1, true, false, READ_COMMITTED},
+            {false, true, 1, false, false, READ_COMMITTED},
+            {false, false, 1, true, false, READ_COMMITTED},
+            {false, false, 1, false, false, READ_COMMITTED},
+
+            // backups = 2
+            {true, true, 2, true, false, READ_COMMITTED},
+            {true, true, 2, false, false, READ_COMMITTED},
+            {true, false, 2, true, false, READ_COMMITTED},
+            {true, false, 2, false, false, READ_COMMITTED},
+            {false, true, 2, true, false, READ_COMMITTED},
+            {false, true, 2, false, false, READ_COMMITTED},
+            {false, false, 2, true, false, READ_COMMITTED},
+            {false, false, 2, false, false, READ_COMMITTED},
+
+            // replicated cache.
+            {true, true, 0, true, true, READ_COMMITTED},
+            {true, false, 0, true, true, READ_COMMITTED},
+            {false, true, 0, true, true, READ_COMMITTED},
+            {false, false, 0, true, true, READ_COMMITTED},
+
+            // REPEATABLE_READ
+            // backups = 0
+            {true, true, 0, true, false, REPEATABLE_READ},
+            {true, true, 0, false, false, REPEATABLE_READ},
+            {true, false, 0, true, false, REPEATABLE_READ},
+            {true, false, 0, false, false, REPEATABLE_READ},
+            {false, true, 0, true, false, REPEATABLE_READ},
+            {false, true, 0, false, false, REPEATABLE_READ},
+            {false, false, 0, true, false, REPEATABLE_READ},
+            {false, false, 0, false, false, REPEATABLE_READ},
+
+            // backups = 1
+            {true, true, 1, true, false, REPEATABLE_READ},
+            {true, true, 1, false, false, REPEATABLE_READ},
+            {true, false, 1, true, false, REPEATABLE_READ},
+            {true, false, 1, false, false, REPEATABLE_READ},
+            {false, true, 1, true, false, REPEATABLE_READ},
+            {false, true, 1, false, false, REPEATABLE_READ},
+            {false, false, 1, true, false, REPEATABLE_READ},
+            {false, false, 1, false, false, REPEATABLE_READ},
+
+            // backups = 2
+            {true, true, 2, true, false, REPEATABLE_READ},
+            {true, true, 2, false, false, REPEATABLE_READ},
+            {true, false, 2, true, false, REPEATABLE_READ},
+            {true, false, 2, false, false, REPEATABLE_READ},
+            {false, true, 2, true, false, REPEATABLE_READ},
+            {false, true, 2, false, false, REPEATABLE_READ},
+            {false, false, 2, true, false, REPEATABLE_READ},
+            {false, false, 2, false, false, REPEATABLE_READ},
+
+            // replicated cache.
+            {true, true, 0, true, true, REPEATABLE_READ},
+            {true, false, 0, true, true, REPEATABLE_READ},
+            {false, true, 0, true, true, REPEATABLE_READ},
+            {false, false, 0, true, true, REPEATABLE_READ},
+        });
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void beforeTestsStarted() throws Exception {
+        super.beforeTestsStarted();
+
+        ignite0 = startGrid(0);
+        ignite1 = startGrid(1);
+        ignite2 = startGrid(2);
+        ignite3 = startGrid(3);
+        client = startClientGrid();
+
+        awaitPartitionMapExchange();
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTestsStopped() throws Exception {
+        stopAllGrids();
+
+        super.afterTestsStopped();
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTest() throws Exception {
+        ignite0.destroyCache(DEFAULT_CACHE_NAME);
+
+        super.afterTest();
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testRollbackToSavepointReleasesRemoteDhtLockAcquireAgain() 
throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int node0Key = primaryKey(cache0);
+        int node1Key = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(node0Key, -1);
+            cache0.put(node1Key, -1);
+        }
+
+        CountDownLatch savepointRolledBackLatch = new CountDownLatch(1);
+        CountDownLatch finishFirstTxLatch = new CountDownLatch(1);
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 2)) {
+                cache0.put(node0Key, 1);
+
+                tx.savepoint("sp");
+
+                cache0.put(node1Key, 1);
+
+                tx.rollbackToSavepoint("sp");
+
+                savepointRolledBackLatch.countDown();
+
+                assertTrue(finishFirstTxLatch.await(10, TimeUnit.SECONDS));
+
+                cache0.put(node1Key, 2);
+
+                tx.commit();
+            }
+        });
+
+        ableToUpdate(node1Key);
+
+        assertFalse(fut.isDone());
+
+        // TODO: IGNITE-28612 Entry visibility violation in transactional 
replication cache with one backup and near.
+        if (initKeies && useNearCache && backups == 1 && spKeyOnTxInitiator && 
!replicated)
+            GridTestUtils.waitForCondition(() -> 
Integer.valueOf(42).equals(cache0.get(node1Key)), 10_000);
+
+        assertEquals(Integer.valueOf(42), cache0.get(node1Key));
+
+        finishFirstTxLatch.countDown();
+
+        fut.get(10_000);
+
+        assertEquals(Integer.valueOf(2), cache0.get(node1Key));
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testOverwriteAndReleaseSavepoint() throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int key = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(key, -1);
+        }
+
+        try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 1)) {
+            cache0.put(key, 1);
+
+            tx.savepoint("sp");
+
+            cache0.put(key, 2);
+
+            tx.savepoint("sp", true);
+
+            cache0.put(key, 3);
+
+            tx.rollbackToSavepoint("sp");
+
+            tx.commit();
+        }
+
+        assertEquals(Integer.valueOf(2), cache0.get(key));
+
+        try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 1)) {
+            tx.savepoint("sp");
+
+            tx.releaseSavepoint("sp");
+
+            GridTestUtils.assertThrowsAnyCause(log,
+                () -> {
+                    tx.rollbackToSavepoint("sp");
+
+                    return null;
+                },
+                IllegalArgumentException.class,
+                "No such savepoint");
+        }
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testRollbackToSavepointReleasesLockForPutRemoveEntry() throws 
Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int key = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(key, -1);
+        }
+
+        CountDownLatch savepointRolledBackLatch = new CountDownLatch(1);
+        CountDownLatch finishFirstTxLatch = new CountDownLatch(1);
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 1)) {
+                tx.savepoint("sp");
+
+                cache0.put(key, 1);
+                cache0.remove(key);
+
+                tx.rollbackToSavepoint("sp");
+
+                savepointRolledBackLatch.countDown();
+
+                assertTrue(finishFirstTxLatch.await(10, TimeUnit.SECONDS));
+
+                tx.commit();
+            }
+        });
+
+        assertTrue(savepointRolledBackLatch.await(10, TimeUnit.SECONDS));
+
+        ableToUpdate(key);
+
+        finishFirstTxLatch.countDown();
+
+        fut.get(10_000);
+
+        assertEquals(Integer.valueOf(42), cache0.get(key));
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testRollbackToSavepoint() {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int key1 = keyForPrimaryAndBackup(ignite0, ignite1);
+        int key2 = keyForPrimaryAndBackup(ignite0, ignite2);
+        int key3 = keyForPrimaryAndBackup(ignite0, ignite3);
+
+        if (initKeies) {
+            cache0.put(key1, -1);
+            cache0.put(key2, -1);
+            cache0.put(key3, -1);
+        }
+
+        try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 3)) {
+            cache0.put(key1, 1);
+
+            tx.savepoint("sp");
+
+            cache0.put(key2, 2);
+
+            tx.rollbackToSavepoint("sp");
+
+            cache0.put(key3, 3);
+
+            tx.commit();
+        }
+
+        assertEquals(Integer.valueOf(1), cache0.get(key1));
+
+        if (initKeies)
+            assertEquals(Integer.valueOf(-1), cache0.get(key2));
+        else
+            assertNull(cache0.get(key2));
+
+        assertEquals(Integer.valueOf(3), cache0.get(key3));
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testClientInitiator() throws Exception {
+        // A client node can not be a primary node for any key.
+        if (spKeyOnTxInitiator)
+            return;
+
+        IgniteCache<Integer, Integer> cache = transactionalCache(client);
+
+        int key1 = keyForPrimaryAndBackup(client, ignite0);
+        int key2 = keyForPrimaryAndBackup(client, ignite1);
+
+        if (initKeies) {
+            cache.put(key1, -1);
+            cache.put(key2, -1);
+        }
+
+        GridCacheVersion[] nearVerRef = new GridCacheVersion[1];
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = client.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 2)) {
+                nearVerRef[0] = ((TransactionProxyImpl<?, 
?>)tx).tx().nearXidVersion();
+
+                Integer val1 = cache.get(key1);
+                Integer val2 = cache.get(key2);
+
+                if (initKeies) {
+                    assertEquals(-1, val1.intValue());
+                    assertEquals(-1, val2.intValue());
+                }
+                else {
+                    assertNull(val1);
+                    assertNull(val2);
+                }
+
+                cache.put(key1, 1);
+                cache.put(key2, 1);
+
+                tx.savepoint("sp");
+
+                cache.put(key1, 2);
+                cache.put(key2, 2);
+
+                tx.rollbackToSavepoint("sp");
+
+                val1 = cache.get(key1);
+                val2 = cache.get(key2);
+
+                assertEquals(1, val1.intValue());
+                assertEquals(1, val2.intValue());
+
+                tx.commit();
+            }
+        });
+
+        fut.get(10_000);
+
+        Integer val1 = cache.get(key1);
+        Integer val2 = cache.get(key2);
+
+        assertEquals(1, val1.intValue());
+        assertEquals(1, val2.intValue());
+
+        assertNoActiveTx(nearVerRef[0]);
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testRollbackAllKey() throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int keyOnInitiator = primaryKey(cache0);
+        int keyOnOtherNode = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(keyOnInitiator, -1);
+            cache0.put(keyOnOtherNode, -1);
+        }
+
+        CountDownLatch rollbackDoneLatch = new CountDownLatch(1);
+        CountDownLatch finishTxLatch = new CountDownLatch(1);
+        GridCacheVersion[] nearVerRef = new GridCacheVersion[1];
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 2)) {
+                nearVerRef[0] = ((TransactionProxyImpl<?, 
?>)tx).tx().nearXidVersion();
+
+                tx.savepoint("sp");
+
+                Integer val1 = cache0.get(keyOnInitiator);
+                Integer val2 = cache0.get(keyOnOtherNode);
+
+                if (initKeies) {
+                    assertEquals(-1, val1.intValue());
+                    assertEquals(-1, val2.intValue());
+                }
+                else {
+                    assertNull(val1);
+                    assertNull(val2);
+                }
+
+                cache0.put(keyOnInitiator, 1);
+                cache0.put(keyOnOtherNode, 1);
+
+                tx.rollbackToSavepoint("sp");
+
+                rollbackDoneLatch.countDown();
+
+                assertTrue(finishTxLatch.await(10, TimeUnit.SECONDS));
+
+                val1 = cache0.get(keyOnInitiator);
+                val2 = cache0.get(keyOnOtherNode);
+
+                assertEquals(42, val1.intValue());
+                assertEquals(42, val2.intValue());
+
+                tx.commit();
+            }
+        });
+
+        assertTrue(rollbackDoneLatch.await(10, TimeUnit.SECONDS));
+
+        assertNoTxStateKeyOnNode(nearVerRef[0], keyOnInitiator);
+        assertNoTxStateKeyOnNode(nearVerRef[0], keyOnOtherNode);
+
+        ableToUpdate(keyOnInitiator);
+        ableToUpdate(keyOnOtherNode);
+
+        finishTxLatch.countDown();
+
+        fut.get(10_000);
+
+        assertNoActiveTx(nearVerRef[0]);
+    }
+
+    /**
+     * @throws Exception If failed.
+     */
+    @Test
+    public void testDhtEntriesAfterRollbackToSavepoint() throws Exception {
+        IgniteCache<Integer, Integer> cache0 = transactionalCache(ignite0);
+
+        int keepTxAliveKey = primaryKey(cache0);
+        int dhtKey = keyForPrimaryAndBackup(ignite0, ignite1);
+
+        if (initKeies) {
+            cache0.put(keepTxAliveKey, -1);
+            cache0.put(dhtKey, -1);
+        }
+
+        CountDownLatch dhtKeyWrittenLatch = new CountDownLatch(1);
+        CountDownLatch proceedRollbackLatch = new CountDownLatch(1);
+        CountDownLatch rollbackDoneLatch = new CountDownLatch(1);
+        CountDownLatch finishTxLatch = new CountDownLatch(1);
+        GridCacheVersion[] nearVerRef = new GridCacheVersion[1];
+
+        IgniteInternalFuture<?> fut = GridTestUtils.runAsync(() -> {
+            try (Transaction tx = ignite0.transactions().txStart(PESSIMISTIC, 
transactionIsolation, 30_000, 2)) {
+                nearVerRef[0] = ((TransactionProxyImpl<?, 
?>)tx).tx().nearXidVersion();
+
+                cache0.put(keepTxAliveKey, 1);
+
+                tx.savepoint("sp");
+
+                cache0.put(dhtKey, 1);
+
+                dhtKeyWrittenLatch.countDown();
+
+                assertTrue(proceedRollbackLatch.await(10, TimeUnit.SECONDS));
+
+                tx.rollbackToSavepoint("sp");
+
+                rollbackDoneLatch.countDown();
+
+                assertTrue(finishTxLatch.await(10, TimeUnit.SECONDS));
+
+                tx.commit();
+            }
+        });
+
+        assertTrue(dhtKeyWrittenLatch.await(10, TimeUnit.SECONDS));
+        assertNotNull(nearVerRef[0]);
+
+        proceedRollbackLatch.countDown();
+
+        assertTrue(rollbackDoneLatch.await(10, TimeUnit.SECONDS));
+
+        assertNoTxStateKeyOnNode(nearVerRef[0], dhtKey);
+
+        finishTxLatch.countDown();
+
+        fut.get(10_000);
+
+        assertNoActiveTx(nearVerRef[0]);
+    }
+
+    /**
+     * Checks that a key is able to be updated.
+     *
+     * @param key Key to update.
+     * @throws Exception If failed.
+     */
+    private void ableToUpdate(int key) {
+        Ignite updateNode = primaryNode(key, DEFAULT_CACHE_NAME);
+
+        updateNode.cache(DEFAULT_CACHE_NAME).put(key, 42);
+    }
+
+    /**
+     * Asserts that no active transaction with the given near version contains 
the specified key
+     * in its write-set or entry map on any node.
+     *
+     * @param nearVer Near transaction version.
+     * @param key Key that must be absent from tx state.
+     * @throws Exception If waiting fails.
+     */
+    private void assertNoTxStateKeyOnNode(GridCacheVersion nearVer, int key) 
throws Exception {
+        for (Ignite ignite : G.allGrids()) {
+            if (ignite.configuration().isClientMode())
+                continue;
+
+            assertTrue(GridTestUtils.waitForCondition(() -> {
+                GridCacheContext<?, ?> cctx = 
((IgniteKernal)ignite).internalCache(DEFAULT_CACHE_NAME).context();
+                IgniteTxKey txKey = cctx.txKey(cctx.toCacheKeyObject(key));
+
+                for (IgniteInternalTx tx : cctx.tm().activeTransactions()) {
+                    if (!nearVer.equals(tx.nearXidVersion()))
+                        continue;
+
+                    if (tx.hasWriteKey(txKey) || tx.entry(txKey) != null)
+                        return false;
+                }
+
+                return true;
+            }, 10_000));
+        }
+    }
+
+    /**
+     * Asserts that no active transaction remains with the near version.
+     *
+     * @param nearVer Near transaction version.
+     * @throws Exception If waiting fails.
+     */
+    private void assertNoActiveTx(GridCacheVersion nearVer) throws Exception {
+        for (Ignite ignite : G.allGrids()) {
+            if (ignite.configuration().isClientMode())
+                continue;
+
+            assertTrue(GridTestUtils.waitForCondition(() -> {
+                GridCacheContext<?, ?> cctx = 
((IgniteKernal)ignite).internalCache(DEFAULT_CACHE_NAME).context();
+                for (IgniteInternalTx tx : cctx.tm().activeTransactions()) {
+                    if (nearVer.equals(tx.nearXidVersion()))
+                        return false;
+                }
+
+                return true;
+            }, 10_000));
+        }
+    }
+
+    /**
+     * Creates transactional cache.
+     *
+     * @param ignite Node.
+     * @return Transactional cache.
+     */
+    private IgniteCache<Integer, Integer> transactionalCache(Ignite ignite) {
+        CacheConfiguration<?, ?> ccfg =
+            new CacheConfiguration<>(DEFAULT_CACHE_NAME)
+                
.setWriteSynchronizationMode(CacheWriteSynchronizationMode.FULL_SYNC)
+                .setNearConfiguration(useNearCache ? new 
NearCacheConfiguration<>() : null)
+                .setAtomicityMode(CacheAtomicityMode.TRANSACTIONAL)
+                .setCacheMode(replicated ? CacheMode.REPLICATED : 
CacheMode.PARTITIONED)
+                .setBackups(backups);
+
+        return (IgniteCache<Integer, Integer>)ignite.createCache(ccfg);
+    }
+
+    /**
+     * Gets key mapped to a given primary.

Review Comment:
   The description and the name are slightly different, the description only 
talks about the primary node in the backup name, it is very confusing.



##########
modules/core/src/main/java/org/apache/ignite/transactions/Transaction.java:
##########
@@ -290,6 +290,57 @@ public interface Transaction extends AutoCloseable, 
IgniteAsyncSupport {
      */
     public void suspend() throws IgniteException;
 
+    /**
+     * Creates a savepoint in the current transaction.
+     * <p>
+     * Savepoints are supported only for explicit transactions with
+     * {@link TransactionConcurrency#PESSIMISTIC} concurrency. The savepoint 
keeps the current transaction state and can
+     * later be used by {@link #rollbackToSavepoint(String)} to discard 
changes made after it was created.
+     *
+     * @param name Savepoint name.
+     * @throws TransactionException If savepoint with the same name already 
exists.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void savepoint(String name);
+
+    /**
+     * Creates a savepoint in the current transaction.
+     * <p>
+     * Savepoints are supported only for explicit transactions with
+     * {@link TransactionConcurrency#PESSIMISTIC} concurrency. If {@code 
overwrite} is {@code true} and a savepoint with
+     * the same name exists, the existing savepoint is replaced with a 
snapshot of the current transaction state.
+     *
+     * @param name Savepoint name.
+     * @param overwrite Whether to overwrite an existing savepoint with the 
same name.
+     * @throws TransactionException If savepoint with the same name already 
exists and {@code overwrite} is
+     *      {@code false}.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void savepoint(String name, boolean overwrite);
+
+    /**
+     * Rolls back transaction changes to the specified savepoint.
+     * <p>
+     * Changes made after the savepoint was created are discarded. Savepoints 
created after the specified savepoint are
+     * released. The transaction remains active and can be committed or rolled 
back after this method returns.
+     *
+     * @param name Savepoint name.
+     * @throws TransactionException If savepoint with the given name does not 
exist.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void rollbackToSavepoint(String name);
+
+    /**
+     * Releases a savepoint. If savepoint does not exist this operation does 
nothing.
+     * <p>
+     * Releasing a savepoint does not roll back transaction changes. It 
removes the specified savepoint and all
+     * savepoints created after it, so none of them can be used by {@link 
#rollbackToSavepoint(String)} anymore.
+     *
+     * @param name Savepoint name.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void releaseSavepoint(String name);

Review Comment:
   I think it's worth adding `@IgniteExperimental`, the api doesn't seem 
finished yet.



##########
modules/core/src/test/java/org/apache/ignite/internal/processors/cache/transactions/TxSavepointParameterizedTest.java:
##########
@@ -0,0 +1,711 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.internal.processors.cache.transactions;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.cache.CacheWriteSynchronizationMode;
+import org.apache.ignite.cluster.ClusterNode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.configuration.NearCacheConfiguration;
+import org.apache.ignite.internal.IgniteInternalFuture;
+import org.apache.ignite.internal.IgniteKernal;
+import org.apache.ignite.internal.processors.cache.GridCacheContext;
+import org.apache.ignite.internal.processors.cache.version.GridCacheVersion;
+import org.apache.ignite.internal.util.typedef.G;
+import org.apache.ignite.testframework.GridTestUtils;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+import org.apache.ignite.transactions.Transaction;
+import org.apache.ignite.transactions.TransactionIsolation;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
+
+import static 
org.apache.ignite.transactions.TransactionConcurrency.PESSIMISTIC;
+import static 
org.apache.ignite.transactions.TransactionIsolation.READ_COMMITTED;
+import static 
org.apache.ignite.transactions.TransactionIsolation.REPEATABLE_READ;
+
+/**
+ * Tests for transaction savepoint API.
+ */
+@RunWith(Parameterized.class)
+public class TxSavepointParameterizedTest extends GridCommonAbstractTest {
+    /** */
+    private static Ignite ignite0;
+
+    /** */
+    private static Ignite ignite1;
+
+    /** */
+    private static Ignite ignite2;
+
+    /** */
+    private static Ignite ignite3;
+
+    /** */
+    private static Ignite client;
+
+    /** */
+    @Parameter(0)
+    public boolean initKeies;
+
+    /** */
+    @Parameter(1)
+    public boolean useNearCache;
+
+    /** */
+    @Parameter(2)
+    public int backups;
+
+    /** */
+    @Parameter(3)
+    public boolean spKeyOnTxInitiator;
+
+    /** */
+    @Parameter(4)
+    public boolean replicated;
+
+    /** */
+    @Parameter(5)
+    public TransactionIsolation transactionIsolation;
+
+    /**
+     * Returns data for test.
+     * @return Test parameters.
+     */
+    @Parameters(name = "initKeies={0}, useNearCache={1}, backups={2}, 
spKeyOnTxInitiator={3}, replicated={4}, txIsolation={5}")
+    public static Collection<Object[]> testData() {
+        return List.of(new Object[][] {
+            // READ_COMMITTED
+            // backups = 0
+            {true, true, 0, true, false, READ_COMMITTED},
+            {true, true, 0, false, false, READ_COMMITTED},
+            {true, false, 0, true, false, READ_COMMITTED},
+            {true, false, 0, false, false, READ_COMMITTED},
+            {false, true, 0, true, false, READ_COMMITTED},
+            {false, true, 0, false, false, READ_COMMITTED},
+            {false, false, 0, true, false, READ_COMMITTED},
+            {false, false, 0, false, false, READ_COMMITTED},
+
+            // backups = 1
+            {true, true, 1, true, false, READ_COMMITTED},
+            {true, true, 1, false, false, READ_COMMITTED},
+            {true, false, 1, true, false, READ_COMMITTED},
+            {true, false, 1, false, false, READ_COMMITTED},
+            {false, true, 1, true, false, READ_COMMITTED},
+            {false, true, 1, false, false, READ_COMMITTED},
+            {false, false, 1, true, false, READ_COMMITTED},
+            {false, false, 1, false, false, READ_COMMITTED},
+
+            // backups = 2
+            {true, true, 2, true, false, READ_COMMITTED},
+            {true, true, 2, false, false, READ_COMMITTED},
+            {true, false, 2, true, false, READ_COMMITTED},
+            {true, false, 2, false, false, READ_COMMITTED},
+            {false, true, 2, true, false, READ_COMMITTED},
+            {false, true, 2, false, false, READ_COMMITTED},
+            {false, false, 2, true, false, READ_COMMITTED},
+            {false, false, 2, false, false, READ_COMMITTED},
+
+            // replicated cache.
+            {true, true, 0, true, true, READ_COMMITTED},
+            {true, false, 0, true, true, READ_COMMITTED},
+            {false, true, 0, true, true, READ_COMMITTED},
+            {false, false, 0, true, true, READ_COMMITTED},
+
+            // REPEATABLE_READ
+            // backups = 0
+            {true, true, 0, true, false, REPEATABLE_READ},
+            {true, true, 0, false, false, REPEATABLE_READ},
+            {true, false, 0, true, false, REPEATABLE_READ},
+            {true, false, 0, false, false, REPEATABLE_READ},
+            {false, true, 0, true, false, REPEATABLE_READ},
+            {false, true, 0, false, false, REPEATABLE_READ},
+            {false, false, 0, true, false, REPEATABLE_READ},
+            {false, false, 0, false, false, REPEATABLE_READ},
+
+            // backups = 1
+            {true, true, 1, true, false, REPEATABLE_READ},
+            {true, true, 1, false, false, REPEATABLE_READ},
+            {true, false, 1, true, false, REPEATABLE_READ},
+            {true, false, 1, false, false, REPEATABLE_READ},
+            {false, true, 1, true, false, REPEATABLE_READ},
+            {false, true, 1, false, false, REPEATABLE_READ},
+            {false, false, 1, true, false, REPEATABLE_READ},
+            {false, false, 1, false, false, REPEATABLE_READ},
+
+            // backups = 2
+            {true, true, 2, true, false, REPEATABLE_READ},
+            {true, true, 2, false, false, REPEATABLE_READ},
+            {true, false, 2, true, false, REPEATABLE_READ},
+            {true, false, 2, false, false, REPEATABLE_READ},
+            {false, true, 2, true, false, REPEATABLE_READ},
+            {false, true, 2, false, false, REPEATABLE_READ},
+            {false, false, 2, true, false, REPEATABLE_READ},
+            {false, false, 2, false, false, REPEATABLE_READ},
+
+            // replicated cache.
+            {true, true, 0, true, true, REPEATABLE_READ},
+            {true, false, 0, true, true, REPEATABLE_READ},
+            {false, true, 0, true, true, REPEATABLE_READ},
+            {false, false, 0, true, true, REPEATABLE_READ},
+        });
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void beforeTestsStarted() throws Exception {
+        super.beforeTestsStarted();
+
+        ignite0 = startGrid(0);
+        ignite1 = startGrid(1);
+        ignite2 = startGrid(2);
+        ignite3 = startGrid(3);
+        client = startClientGrid();
+
+        awaitPartitionMapExchange();
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTestsStopped() throws Exception {

Review Comment:
   missing `beforeTestsStarted`



##########
modules/core/src/main/java/org/apache/ignite/internal/processors/cache/transactions/IgniteTxEntry.java:
##########
@@ -378,6 +378,104 @@ public IgniteTxEntry cleanCopy(GridCacheContext<?, ?> 
ctx) {
         return cp;
     }
 
+    /**
+     * @return Deep-enough copy of this entry to restore its state later.
+     */
+    public IgniteTxEntry copy() {
+        IgniteTxEntry cp = new IgniteTxEntry();
+
+        cp.tx = tx;
+        cp.key = key;
+        cp.cacheId = cacheId;
+        cp.txKey = txKey;
+        cp.ctx = ctx;
+        cp.val = copyHolder(val);
+        cp.prevVal.value(prevVal.operation(), prevVal.value(), 
prevVal.hasWriteValue(), prevVal.hasReadValue());
+        cp.oldVal = copyHolder(oldVal);
+        cp.entryProcessorsCol = entryProcessorsCol == null ? null : new 
LinkedList<>(entryProcessorsCol);
+        cp.entryProcessorCalcVal = entryProcessorCalcVal;
+        cp.transformClosBytes = transformClosBytes;
+        cp.ttl = ttl;
+        cp.conflictExpireTime = conflictExpireTime;
+        cp.conflictVer = conflictVer;
+        cp.explicitVer = explicitVer;
+        cp.dhtVer = dhtVer;
+        cp.filters = filters;
+        cp.filtersPassed = filtersPassed;
+        cp.filtersSet = filtersSet;
+        cp.entry = entry;
+        cp.prepared = prepared;
+        cp.locked = locked;
+        cp.nodeId = nodeId;
+        cp.locMapped = locMapped;
+        cp.expiryPlc = expiryPlc;
+        cp.transferExpiryPlc = transferExpiryPlc;
+        cp.expiryPlcBytes = expiryPlcBytes;
+        cp.flags = flags;
+        cp.partUpdateCntr = partUpdateCntr;
+        cp.serReadVer = serReadVer;
+
+        return cp;
+    }
+
+    /**
+     * Restores this entry from a previously captured snapshot.
+     *
+     * @param snapshot Snapshot.
+     */
+    public void restoreFrom(IgniteTxEntry snapshot) {
+        tx = snapshot.tx;
+        key = snapshot.key;
+        cacheId = snapshot.cacheId;
+        txKey = snapshot.txKey;
+        ctx = snapshot.ctx;
+        val = copyHolder(snapshot.val);
+        prevVal.value(
+            snapshot.prevVal.operation(),
+            snapshot.prevVal.value(),
+            snapshot.prevVal.hasWriteValue(),
+            snapshot.prevVal.hasReadValue()
+        );
+        oldVal = copyHolder(snapshot.oldVal);
+        entryProcessorsCol = snapshot.entryProcessorsCol == null ? null : new 
LinkedList<>(snapshot.entryProcessorsCol);
+        entryProcessorCalcVal = snapshot.entryProcessorCalcVal;
+        transformClosBytes = snapshot.transformClosBytes;
+        ttl = snapshot.ttl;
+        conflictExpireTime = snapshot.conflictExpireTime;
+        conflictVer = snapshot.conflictVer;
+        explicitVer = snapshot.explicitVer;
+        dhtVer = snapshot.dhtVer;
+        filters = snapshot.filters;
+        filtersPassed = snapshot.filtersPassed;
+        filtersSet = snapshot.filtersSet;
+        entry = snapshot.entry;
+        prepared = snapshot.prepared;
+        locked = snapshot.locked;
+        nodeId = snapshot.nodeId;
+        locMapped = snapshot.locMapped;
+        expiryPlc = snapshot.expiryPlc;
+        transferExpiryPlc = snapshot.transferExpiryPlc;
+        expiryPlcBytes = snapshot.expiryPlcBytes;
+        flags = snapshot.flags;
+        partUpdateCntr = snapshot.partUpdateCntr;
+        serReadVer = snapshot.serReadVer;
+    }
+
+    /**
+     * @param holder Holder to copy.
+     * @return Copy.
+     */
+    private static TxEntryValueHolder copyHolder(@Nullable TxEntryValueHolder 
holder) {

Review Comment:
   ```suggestion
       private static @Nullable TxEntryValueHolder copyHolder(@Nullable 
TxEntryValueHolder holder) {
   ```



##########
modules/core/src/main/java/org/apache/ignite/transactions/Transaction.java:
##########
@@ -290,6 +290,57 @@ public interface Transaction extends AutoCloseable, 
IgniteAsyncSupport {
      */
     public void suspend() throws IgniteException;
 
+    /**
+     * Creates a savepoint in the current transaction.
+     * <p>
+     * Savepoints are supported only for explicit transactions with
+     * {@link TransactionConcurrency#PESSIMISTIC} concurrency. The savepoint 
keeps the current transaction state and can
+     * later be used by {@link #rollbackToSavepoint(String)} to discard 
changes made after it was created.
+     *
+     * @param name Savepoint name.
+     * @throws TransactionException If savepoint with the same name already 
exists.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void savepoint(String name);

Review Comment:
   I think it's worth adding `@IgniteExperimental`, the api doesn't seem 
finished yet.



##########
modules/core/src/main/java/org/apache/ignite/transactions/Transaction.java:
##########
@@ -290,6 +290,57 @@ public interface Transaction extends AutoCloseable, 
IgniteAsyncSupport {
      */
     public void suspend() throws IgniteException;
 
+    /**
+     * Creates a savepoint in the current transaction.
+     * <p>
+     * Savepoints are supported only for explicit transactions with
+     * {@link TransactionConcurrency#PESSIMISTIC} concurrency. The savepoint 
keeps the current transaction state and can
+     * later be used by {@link #rollbackToSavepoint(String)} to discard 
changes made after it was created.
+     *
+     * @param name Savepoint name.
+     * @throws TransactionException If savepoint with the same name already 
exists.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void savepoint(String name);
+
+    /**
+     * Creates a savepoint in the current transaction.
+     * <p>
+     * Savepoints are supported only for explicit transactions with
+     * {@link TransactionConcurrency#PESSIMISTIC} concurrency. If {@code 
overwrite} is {@code true} and a savepoint with
+     * the same name exists, the existing savepoint is replaced with a 
snapshot of the current transaction state.
+     *
+     * @param name Savepoint name.
+     * @param overwrite Whether to overwrite an existing savepoint with the 
same name.
+     * @throws TransactionException If savepoint with the same name already 
exists and {@code overwrite} is
+     *      {@code false}.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void savepoint(String name, boolean overwrite);
+
+    /**
+     * Rolls back transaction changes to the specified savepoint.
+     * <p>
+     * Changes made after the savepoint was created are discarded. Savepoints 
created after the specified savepoint are
+     * released. The transaction remains active and can be committed or rolled 
back after this method returns.

Review Comment:
   Maybe not `released` but "rolled back" ?



##########
modules/core/src/main/java/org/apache/ignite/transactions/Transaction.java:
##########
@@ -290,6 +290,57 @@ public interface Transaction extends AutoCloseable, 
IgniteAsyncSupport {
      */
     public void suspend() throws IgniteException;
 
+    /**
+     * Creates a savepoint in the current transaction.
+     * <p>
+     * Savepoints are supported only for explicit transactions with
+     * {@link TransactionConcurrency#PESSIMISTIC} concurrency. The savepoint 
keeps the current transaction state and can
+     * later be used by {@link #rollbackToSavepoint(String)} to discard 
changes made after it was created.
+     *
+     * @param name Savepoint name.
+     * @throws TransactionException If savepoint with the same name already 
exists.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void savepoint(String name);
+
+    /**
+     * Creates a savepoint in the current transaction.
+     * <p>
+     * Savepoints are supported only for explicit transactions with
+     * {@link TransactionConcurrency#PESSIMISTIC} concurrency. If {@code 
overwrite} is {@code true} and a savepoint with
+     * the same name exists, the existing savepoint is replaced with a 
snapshot of the current transaction state.
+     *
+     * @param name Savepoint name.
+     * @param overwrite Whether to overwrite an existing savepoint with the 
same name.
+     * @throws TransactionException If savepoint with the same name already 
exists and {@code overwrite} is
+     *      {@code false}.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void savepoint(String name, boolean overwrite);
+
+    /**
+     * Rolls back transaction changes to the specified savepoint.
+     * <p>
+     * Changes made after the savepoint was created are discarded. Savepoints 
created after the specified savepoint are
+     * released. The transaction remains active and can be committed or rolled 
back after this method returns.
+     *
+     * @param name Savepoint name.
+     * @throws TransactionException If savepoint with the given name does not 
exist.
+     * @throws IgniteException If savepoints are not supported for this 
transaction.
+     */
+    public void rollbackToSavepoint(String name);
+
+    /**
+     * Releases a savepoint. If savepoint does not exist this operation does 
nothing.
+     * <p>
+     * Releasing a savepoint does not roll back transaction changes. It 
removes the specified savepoint and all

Review Comment:
   Maybe indicate that the resources used by the savepoint are being freed?



##########
modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/near/GridNearTxLocal.java:
##########
@@ -219,6 +224,9 @@ public class GridNearTxLocal extends GridDhtTxLocalAdapter 
implements GridTimeou
     /** Tx label. */
     @Nullable private final String lb;
 
+    /** Savepoints created for this transaction. */

Review Comment:
   ```suggestion
       /** Savepoints created for this transaction. Guarded by {@code this}. */
   ```



##########
modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/near/GridNearTxLocal.java:
##########
@@ -219,6 +224,9 @@ public class GridNearTxLocal extends GridDhtTxLocalAdapter 
implements GridTimeou
     /** Tx label. */
     @Nullable private final String lb;
 
+    /** Savepoints created for this transaction. */
+    private LinkedList<TxSavepoint> savepoints;

Review Comment:
   `LinkedList` is quite outdated, I think we can replace it with `List` and 
use `ArrayList`.



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