timoninmaxim commented on code in PR #311:
URL: https://github.com/apache/ignite-extensions/pull/311#discussion_r2215846389


##########
modules/cdc-ext/src/main/java/org/apache/ignite/cdc/postgresql/IgniteToPostgreSqlCdcApplier.java:
##########
@@ -0,0 +1,661 @@
+/*
+ * 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.cdc.postgresql;
+
+import java.math.BigDecimal;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.sql.Types;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import javax.sql.DataSource;
+import org.apache.ignite.IgniteException;
+import org.apache.ignite.IgniteLogger;
+import org.apache.ignite.binary.BinaryObject;
+import org.apache.ignite.cache.CacheEntryVersion;
+import org.apache.ignite.cache.QueryEntity;
+import org.apache.ignite.cdc.CdcCacheEvent;
+import org.apache.ignite.cdc.CdcEvent;
+import org.apache.ignite.internal.util.typedef.F;
+
+import static 
org.apache.ignite.internal.processors.cache.GridCacheUtils.UNDEFINED_CACHE_ID;
+
+/** */
+public class IgniteToPostgreSqlCdcApplier {
+    /** */
+    public static final String DFLT_SQL_TYPE = "OTHER";
+
+    /** */
+    public static final Map<String, String> JAVA_TO_SQL_TYPES;
+
+    static {
+        Map<String, String> map = new HashMap<>();
+
+        map.put("java.lang.String", "VARCHAR");
+        map.put("java.lang.Integer", "INT");
+        map.put("int", "INT");
+        map.put("java.lang.Long", "BIGINT");
+        map.put("long", "BIGINT");
+        map.put("java.lang.Boolean", "BOOLEAN");
+        map.put("boolean", "BOOLEAN");
+        map.put("java.lang.Double", "DOUBLE PRECISION");
+        map.put("double", "DOUBLE PRECISION");
+        map.put("java.lang.Float", "REAL");
+        map.put("float", "REAL");
+        map.put("java.math.BigDecimal", "DECIMAL");
+        map.put("java.lang.Short", "SMALLINT");
+        map.put("short", "SMALLINT");
+        map.put("java.lang.Byte", "SMALLINT");
+        map.put("byte", "SMALLINT");
+        map.put("java.util.UUID", "UUID");
+        map.put("[B", "BYTEA");
+        map.put("java.lang.Object", "OTHER");
+
+        JAVA_TO_SQL_TYPES = Collections.unmodifiableMap(map);
+    }
+
+    /** */
+    private final DataSource dataSrc;
+
+    /** */
+    private final boolean autoCommit;
+
+    /** */
+    private final long maxBatchSize;
+
+    /** */
+    private final IgniteLogger log;
+
+    /** */
+    private final Map<Integer, String> cacheIdToUpsertQry = new HashMap<>();
+
+    /** */
+    private final Map<Integer, String> cacheIdToDeleteQry = new HashMap<>();
+
+    /** */
+    private final Map<Integer, Set<String>> cacheIdToPrimaryKeys = new 
HashMap<>();
+
+    /** */
+    private final Map<Integer, Set<String>> cacheIdToFields = new HashMap<>();
+
+    /** */
+    private final Set<Object> curKeys = new HashSet<>();

Review Comment:
   Never populated



##########
modules/cdc-ext/src/main/java/org/apache/ignite/cdc/postgresql/IgniteToPostgreSqlCdcConsumer.java:
##########
@@ -0,0 +1,259 @@
+/*
+ * 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.cdc.postgresql;
+
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.Set;
+import java.util.stream.Collectors;
+import javax.sql.DataSource;
+import org.apache.ignite.IgniteLogger;
+import org.apache.ignite.binary.BinaryType;
+import org.apache.ignite.cdc.CdcCacheEvent;
+import org.apache.ignite.cdc.CdcConsumer;
+import org.apache.ignite.cdc.CdcEvent;
+import org.apache.ignite.cdc.TypeMapping;
+import org.apache.ignite.internal.processors.metric.MetricRegistryImpl;
+import org.apache.ignite.internal.processors.metric.impl.AtomicLongMetric;
+import org.apache.ignite.internal.util.typedef.F;
+import org.apache.ignite.internal.util.typedef.internal.A;
+import org.apache.ignite.internal.util.typedef.internal.CU;
+import org.apache.ignite.metric.MetricRegistry;
+import org.apache.ignite.resources.LoggerResource;
+
+/**
+ * This class represents a consumer component that replicates cache changes 
from Apache Ignite to PostgreSQL using
+ * Change Data Capture (CDC) mechanism. It applies events to PostgreSQL via 
batch-prepared SQL statements, ensuring
+ * efficient handling of large volumes of updates.
+ *
+ * <p>Additionally, it provides methods for initializing connections, managing 
transactions, and performing atomic batches
+ * of writes.</p>
+ */
+public class IgniteToPostgreSqlCdcConsumer implements CdcConsumer {
+    /** */
+    public static final String EVTS_SENT_CNT = "EventsCount";
+
+    /** */
+    public static final String EVTS_SENT_CNT_DESC = "Count of events applied 
to PostgreSQL";
+
+    /** */
+    public static final String LAST_EVT_SENT_TIME = "LastEventTime";
+
+    /** */
+    public static final String LAST_EVT_SENT_TIME_DESC = "Timestamp of last 
applied event to PostgreSQL";
+
+    /** */
+    private static final boolean DFLT_IS_ONLY_PRIMARY = true;
+
+    /** */
+    private static final long DFLT_BATCH_SIZE = 1024;
+
+    /** */
+    private static final boolean DFLT_CREATE_TABLES = false;
+
+    /** */
+    private static final boolean DFLT_AUTO_COMMIT = false;
+
+    /** */
+    private DataSource dataSrc;
+
+    /** Collection of cache names which will be replicated to PostgreSQL. */
+    private Collection<String> caches;
+
+    /** */
+    private boolean onlyPrimary = DFLT_IS_ONLY_PRIMARY;
+
+    /** */
+    private long maxBatchSize = DFLT_BATCH_SIZE;
+
+    /** */
+    private boolean createTables = DFLT_CREATE_TABLES;
+
+    /** */
+    private boolean autoCommit = DFLT_AUTO_COMMIT;
+
+    /** Log. */
+    @LoggerResource
+    private IgniteLogger log;
+
+    /** Cache IDs. */
+    private Set<Integer> cachesIds;
+
+    /** Applier instance responsible for applying individual CDC events to 
PostgreSQL. */
+    private IgniteToPostgreSqlCdcApplier applier;
+
+    /** Count of events applied to PostgreSQL. */
+    private AtomicLongMetric evtsCnt;
+
+    /** Timestamp of last applied batch to PostgreSQL. */
+    private AtomicLongMetric lastEvtTs;
+
+    /** {@inheritDoc} */
+    @Override public void start(MetricRegistry reg) {
+        A.notNull(dataSrc, "dataSource");
+        A.notEmpty(caches, "caches");
+
+        cachesIds = caches.stream()
+            .map(CU::cacheId)
+            .collect(Collectors.toSet());
+
+        applier = new IgniteToPostgreSqlCdcApplier(dataSrc, autoCommit, 
maxBatchSize, log);
+
+        MetricRegistryImpl mreg = (MetricRegistryImpl)reg;
+
+        this.evtsCnt = mreg.longMetric(EVTS_SENT_CNT, EVTS_SENT_CNT_DESC);
+        this.lastEvtTs = mreg.longMetric(LAST_EVT_SENT_TIME, 
LAST_EVT_SENT_TIME_DESC);
+
+        if (log.isInfoEnabled())
+            log.info("CDC Ignite to PostgreSQL start-up [cacheIds=" + 
cachesIds + ']');
+    }
+
+    /** {@inheritDoc} */
+    @Override public boolean onEvents(Iterator<CdcEvent> events) {
+        Iterator<CdcEvent> filtered = F.iterator(
+            events,
+            F.identity(),
+            true,
+            evt -> !onlyPrimary || evt.primary(),
+            evt -> cachesIds.contains(evt.cacheId()));
+
+        long evtsSent = applier.applyEvents(filtered);
+
+        if (evtsSent > 0) {
+            evtsCnt.add(evtsSent);
+            lastEvtTs.value(System.currentTimeMillis());
+
+            if (log.isInfoEnabled())
+                log.info("Events applied [evtsApplied=" + evtsCnt.value() + 
']');
+        }
+
+        return true;
+    }
+
+    /** {@inheritDoc} */
+    @Override public void onTypes(Iterator<BinaryType> types) {
+        types.forEachRemaining(e -> {
+            // Just skip. Handle of cache events not supported.
+        });
+    }
+
+    /** {@inheritDoc} */
+    @Override public void onMappings(Iterator<TypeMapping> mappings) {
+        mappings.forEachRemaining(e -> {
+            // Just skip. Handle of cache events not supported.
+        });
+    }
+
+    /** {@inheritDoc} */
+    @Override public void onCacheChange(Iterator<CdcCacheEvent> cacheEvents) {
+        Iterator<CdcCacheEvent> filtered = F.iterator(
+            cacheEvents,
+            F.identity(),
+            true,
+            evt -> cachesIds.contains(evt.cacheId()));
+
+        long tablesCreated = applier.applyCacheEvents(filtered, createTables);
+
+        if (tablesCreated > 0 && log.isInfoEnabled())
+            log.info("Cache changes applied [tablesCreatedCnt=" + 
tablesCreated + ']');
+    }
+
+    /** {@inheritDoc} */
+    @Override public void onCacheDestroy(Iterator<Integer> caches) {
+        caches.forEachRemaining(e -> {
+            // Just skip. Handle of cache events not supported.
+        });
+    }
+
+    /** {@inheritDoc} */
+    @Override public void stop() {
+
+    }
+
+    /**
+     * Sets the datasource configuration for connecting to the PostgreSQL 
database.
+     *
+     * @param dataSrc Configured data source.
+     * @return {@code this} for chaining.
+     */
+    public IgniteToPostgreSqlCdcConsumer setDataSource(DataSource dataSrc) {
+        this.dataSrc = dataSrc;
+
+        return this;
+    }
+
+    /**
+     * Sets cache names to replicate.
+     *
+     * @param caches Cache names.
+     * @return {@code this} for chaining.
+     */
+    public IgniteToPostgreSqlCdcConsumer setCaches(Set<String> caches) {
+        this.caches = caches;
+
+        return this;
+    }
+
+    /**
+     * Enables/disables filtering to accept only primary-node originated 
events.
+     *
+     * @param onlyPrimary True to restrict replication to primary events only.
+     * @return {@code this} for chaining.
+     */
+    public IgniteToPostgreSqlCdcConsumer setOnlyPrimary(boolean onlyPrimary) {
+        this.onlyPrimary = onlyPrimary;
+
+        return this;
+    }
+
+    /**
+     * Sets maximum batch size that will be applied to PostgreSql in one 
commit.

Review Comment:
   In one commit in case of `autoCommit = false`



##########
modules/cdc-ext/src/main/java/org/apache/ignite/cdc/postgresql/IgniteToPostgreSqlCdcApplier.java:
##########
@@ -0,0 +1,661 @@
+/*
+ * 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.cdc.postgresql;
+
+import java.math.BigDecimal;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.sql.Types;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import javax.sql.DataSource;
+import org.apache.ignite.IgniteException;
+import org.apache.ignite.IgniteLogger;
+import org.apache.ignite.binary.BinaryObject;
+import org.apache.ignite.cache.CacheEntryVersion;
+import org.apache.ignite.cache.QueryEntity;
+import org.apache.ignite.cdc.CdcCacheEvent;
+import org.apache.ignite.cdc.CdcEvent;
+import org.apache.ignite.internal.util.typedef.F;
+
+import static 
org.apache.ignite.internal.processors.cache.GridCacheUtils.UNDEFINED_CACHE_ID;
+
+/** */
+public class IgniteToPostgreSqlCdcApplier {
+    /** */
+    public static final String DFLT_SQL_TYPE = "OTHER";
+
+    /** */
+    public static final Map<String, String> JAVA_TO_SQL_TYPES;
+
+    static {
+        Map<String, String> map = new HashMap<>();
+
+        map.put("java.lang.String", "VARCHAR");
+        map.put("java.lang.Integer", "INT");
+        map.put("int", "INT");
+        map.put("java.lang.Long", "BIGINT");
+        map.put("long", "BIGINT");
+        map.put("java.lang.Boolean", "BOOLEAN");
+        map.put("boolean", "BOOLEAN");
+        map.put("java.lang.Double", "DOUBLE PRECISION");
+        map.put("double", "DOUBLE PRECISION");
+        map.put("java.lang.Float", "REAL");
+        map.put("float", "REAL");
+        map.put("java.math.BigDecimal", "DECIMAL");
+        map.put("java.lang.Short", "SMALLINT");
+        map.put("short", "SMALLINT");
+        map.put("java.lang.Byte", "SMALLINT");
+        map.put("byte", "SMALLINT");
+        map.put("java.util.UUID", "UUID");
+        map.put("[B", "BYTEA");
+        map.put("java.lang.Object", "OTHER");
+
+        JAVA_TO_SQL_TYPES = Collections.unmodifiableMap(map);
+    }
+
+    /** */
+    private final DataSource dataSrc;
+
+    /** */
+    private final boolean autoCommit;
+
+    /** */
+    private final long maxBatchSize;
+
+    /** */
+    private final IgniteLogger log;
+
+    /** */
+    private final Map<Integer, String> cacheIdToUpsertQry = new HashMap<>();
+
+    /** */
+    private final Map<Integer, String> cacheIdToDeleteQry = new HashMap<>();
+
+    /** */
+    private final Map<Integer, Set<String>> cacheIdToPrimaryKeys = new 
HashMap<>();
+
+    /** */
+    private final Map<Integer, Set<String>> cacheIdToFields = new HashMap<>();
+
+    /** */
+    private final Set<Object> curKeys = new HashSet<>();
+
+    /**
+     * @param dataSrc {@link DataSource} - connection pool to PostgreSql
+     * @param autoCommit - autoCommit flag for batch execution
+     * @param maxBatchSize the maximum number of CDC events to include in a 
single batch
+     * @param log the {@link IgniteLogger} instance used for logging CDC 
processing events
+     */
+    public IgniteToPostgreSqlCdcApplier(DataSource dataSrc, boolean 
autoCommit, long maxBatchSize, IgniteLogger log) {
+        this.dataSrc = dataSrc;
+        this.autoCommit = autoCommit;
+        this.maxBatchSize = maxBatchSize;
+        this.log = log;
+    }
+
+    /**
+     * @param evts an {@link Iterator} of {@link CdcEvent} objects to be 
applied
+     * @return the total number of events successfully batched and executed
+     */
+    public long applyEvents(Iterator<CdcEvent> evts) {
+        try (Connection conn = dataSrc.getConnection()) {
+            conn.setAutoCommit(autoCommit);
+
+            long res = applyEvents(conn, evts);
+
+            conn.commit();
+
+            return res;
+        }
+        catch (Throwable e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException("CDC failure", e);
+        }
+    }
+
+    /**
+     * @param conn connection to PostgreSql
+     * @param evts an {@link Iterator} of {@link CdcEvent} objects to be 
applied
+     * @return the total number of events successfully batched and executed
+     */
+    private long applyEvents(Connection conn, Iterator<CdcEvent> evts) {
+        long evtsApplied = 0;
+
+        int currCacheId = UNDEFINED_CACHE_ID;
+        boolean prevOpIsDelete = false;
+        
+        PreparedStatement curPrepStmt = null;
+        CdcEvent evt;
+
+        while (evts.hasNext()) {
+            evt = evts.next();
+
+            if (log.isDebugEnabled())
+                log.debug("Event received [evt=" + evt + ']');
+
+            if (currCacheId != evt.cacheId() || prevOpIsDelete ^ (evt.value() 
== null)) {
+                if (curPrepStmt != null)
+                    evtsApplied += executeBatch(curPrepStmt);
+
+                currCacheId = evt.cacheId();
+                prevOpIsDelete = evt.value() == null;
+
+                curPrepStmt = prepareStatement(conn, evt);
+            }
+
+            if (curKeys.size() >= maxBatchSize || curKeys.contains(evt.key()))
+                evtsApplied += executeBatch(curPrepStmt);
+
+            addEvent(curPrepStmt, evt);
+        }
+
+        if (currCacheId != UNDEFINED_CACHE_ID)
+            evtsApplied += executeBatch(curPrepStmt);
+
+        return evtsApplied;
+    }
+
+    /**
+     * @param curPrepStmt {@link PreparedStatement}
+     * @return the total number of batches successfully executed. One CdcEvent 
- one batch.
+     */
+    private int executeBatch(PreparedStatement curPrepStmt) {
+        try {
+            curKeys.clear();
+
+            if (log.isDebugEnabled())
+                log.debug("Applying batch " + curPrepStmt.toString());
+
+            if (!curPrepStmt.isClosed())
+                return curPrepStmt.executeBatch().length;
+
+            throw new IgniteException("Tried to execute on closed prepared 
statement!");
+        }
+        catch (SQLException e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException(e);
+        }
+    }
+
+    /**
+     * @param conn connection to PostgreSql
+     * @param evt {@link CdcEvent}
+     * @return relevant {@link PreparedStatement}
+     */
+    private PreparedStatement prepareStatement(Connection conn, CdcEvent evt) {
+        String sqlQry;
+
+        if (evt.value() == null)
+            sqlQry = cacheIdToDeleteQry.get(evt.cacheId());
+        else
+            sqlQry = cacheIdToUpsertQry.get(evt.cacheId());
+
+        if (sqlQry == null)
+            throw new IgniteException("No SQL query is found for cacheId=" + 
evt.cacheId());
+
+        if (log.isDebugEnabled())
+            log.debug("Statement updated [cacheId=" + evt.cacheId() + ", 
sqlQry=" + sqlQry + ']');
+
+        try {
+            return conn.prepareStatement(sqlQry);
+        }
+        catch (SQLException e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException(e);
+        }
+    }
+
+    /**
+     * @param curPrepStmt {@link PreparedStatement}
+     * @param evt {@link CdcEvent}
+     */
+    private void addEvent(PreparedStatement curPrepStmt, CdcEvent evt) {
+        try {
+            if (evt.value() == null)
+                addEvent(curPrepStmt, evt, true);
+            else {
+                int idx = addEvent(curPrepStmt, evt, false);
+
+                curPrepStmt.setBytes(idx, encodeVersion(evt.version()));
+            }
+
+            curPrepStmt.addBatch();
+        }
+        catch (Throwable e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException(e);
+        }
+    }
+
+    /**
+     * @param curPrepStmt {@link PreparedStatement}
+     * @param evt {@link CdcEvent}
+     * @param isDelete - flag that indicate delete sql statement usage
+     * @return number of filled values
+     */
+    private int addEvent(PreparedStatement curPrepStmt, CdcEvent evt, boolean 
isDelete) throws SQLException {
+        Iterator<String> itFields = isDelete ?
+            cacheIdToPrimaryKeys.get(evt.cacheId()).iterator() :
+            cacheIdToFields.get(evt.cacheId()).iterator();
+
+        String field;
+
+        BinaryObject keyObj = (evt.key() instanceof BinaryObject) ? 
(BinaryObject)evt.key() : null;
+        BinaryObject valObj = (evt.value() instanceof BinaryObject) ? 
(BinaryObject)evt.value() : null;
+
+        int idx = 1;
+        Object obj;
+
+        while (itFields.hasNext()) {
+            field = itFields.next();
+
+            if (cacheIdToPrimaryKeys.get(evt.cacheId()).contains(field))
+                if (keyObj != null)
+                    obj = keyObj.field(field);
+                else
+                    obj = evt.key();
+            else
+                if (valObj != null)
+                    obj = valObj.field(field);
+                else
+                    obj = evt.value();
+
+            addObject(curPrepStmt, idx, obj);
+
+            idx++;
+        }
+
+        return idx;
+    }
+
+    /**
+     * Sets a value in the PreparedStatement at the given index using the 
appropriate setter
+     * based on the runtime type of the object.
+     * @param curPrepStmt {@link PreparedStatement}
+     * @param idx value index in {@link PreparedStatement}
+     * @param obj value
+     */
+    private void addObject(PreparedStatement curPrepStmt, int idx, Object obj) 
throws SQLException {
+        if (obj == null) {
+            curPrepStmt.setObject(idx, null);
+
+            return;
+        }
+
+        if (obj instanceof String)
+            curPrepStmt.setString(idx, (String)obj);
+        else if (obj instanceof Integer)
+            curPrepStmt.setInt(idx, (Integer)obj);
+        else if (obj instanceof Long)
+            curPrepStmt.setLong(idx, (Long)obj);
+        else if (obj instanceof Short)
+            curPrepStmt.setShort(idx, (Short)obj);
+        else if (obj instanceof Byte)
+            curPrepStmt.setByte(idx, (Byte)obj);
+        else if (obj instanceof Boolean)
+            curPrepStmt.setBoolean(idx, (Boolean)obj);
+        else if (obj instanceof Float)
+            curPrepStmt.setFloat(idx, (Float)obj);
+        else if (obj instanceof Double)
+            curPrepStmt.setDouble(idx, (Double)obj);
+        else if (obj instanceof BigDecimal)
+            curPrepStmt.setBigDecimal(idx, (BigDecimal)obj);
+        else if (obj instanceof UUID)
+            curPrepStmt.setObject(idx, obj, Types.OTHER); // PostgreSQL 
expects UUID as OTHER
+        else if (obj instanceof byte[])
+            curPrepStmt.setBytes(idx, (byte[])obj);
+        else
+            curPrepStmt.setObject(idx, obj);
+    }
+
+    /**
+     * @param evts an {@link Iterator} of {@link CdcCacheEvent} objects to 
apply
+     * @param createTables tables creation flag. If true - attempt to create 
tables will be made.
+     * @return Number of applied events.
+     */
+    public long applyCacheEvents(Iterator<CdcCacheEvent> evts, boolean 
createTables) {
+        CdcCacheEvent evt;
+        QueryEntity entity;
+
+        long cnt = 0;
+
+        while (evts.hasNext()) {
+            evt = evts.next();
+
+            if (evt.queryEntities().size() != 1)
+                throw new IgniteException("There should be exactly 1 
QueryEntity for cacheId: " + evt.cacheId());
+
+            entity = evt.queryEntities().iterator().next();
+
+            if (createTables)
+                createTableIfNotExists(entity);
+
+            cacheIdToUpsertQry.put(evt.cacheId(), getUpsertSqlQry(entity));
+
+            cacheIdToDeleteQry.put(evt.cacheId(), getDeleteSqlQry(entity));
+
+            cacheIdToPrimaryKeys.put(evt.cacheId(), getPrimaryKeys(entity));
+
+            cacheIdToFields.put(evt.cacheId(), entity.getFields().keySet());
+
+            if (log.isInfoEnabled())
+                log.info("Cache table created [tableName=" + 
entity.getTableName() +
+                    ", columns=" + entity.getFields().keySet() + ']');
+
+            cnt++;
+        }
+
+        return cnt;
+    }
+
+    /**
+     * @param entity the {@link QueryEntity} describing the table schema to 
create
+     */
+    private void createTableIfNotExists(QueryEntity entity) {
+        String createSqlStmt = getCreateTableSqlStatement(entity);
+
+        try (Connection conn = dataSrc.getConnection(); Statement stmt = 
conn.createStatement()) {
+            stmt.execute(createSqlStmt);
+        }
+        catch (SQLException e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException(e);
+        }
+    }
+
+    /**
+     * Generates the SQL statement for creating a table.
+     *
+     * @param entity QueryEntity instance describing the cache structure.
+     * @return SQL statement for creating a table.
+     */
+    private String getCreateTableSqlStatement(QueryEntity entity) {
+        StringBuilder ddl = new StringBuilder("CREATE TABLE IF NOT EXISTS 
").append(entity.getTableName()).append(" (");
+
+        addFieldsAndTypes(entity, ddl);
+
+        ddl.append(", version BYTEA NOT NULL");
+
+        ddl.append(", PRIMARY KEY (");
+
+        addPrimaryKeys(entity, ddl);
+
+        ddl.append(')').append(')');
+
+        return ddl.toString();
+    }
+
+    /**
+     * Constructs DDL-compatible SQL fragment listing fields along with their 
mapped SQL types.
+     *
+     * @param entity QueryEntity instance describing the cache structure.
+     * @param sql Target StringBuilder where the result will be appended.
+     */
+    private void addFieldsAndTypes(QueryEntity entity, StringBuilder sql) {
+        Iterator<Map.Entry<String, String>> iter = 
entity.getFields().entrySet().iterator();
+
+        Map.Entry<String, String> field;
+        String type;
+
+        Integer precision;
+        Integer scale;
+
+        while (iter.hasNext()) {
+            field = iter.next();
+            type = JAVA_TO_SQL_TYPES.getOrDefault(field.getValue(), 
DFLT_SQL_TYPE);
+
+            sql.append(field.getKey()).append(" ").append(type);
+
+            precision = entity.getFieldsPrecision().get(field.getKey());
+            scale = entity.getFieldsScale().get(field.getKey());
+
+            if (precision != null && precision > 0) {
+                if (type.equals("VARCHAR") || type.equals("TIME") || 
type.equals("TIMESTAMP") ||

Review Comment:
   Let's make a set for these types. For "REAL" it requires to make 7 compares



##########
modules/cdc-ext/src/main/java/org/apache/ignite/cdc/postgresql/IgniteToPostgreSqlCdcApplier.java:
##########
@@ -0,0 +1,661 @@
+/*
+ * 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.cdc.postgresql;
+
+import java.math.BigDecimal;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.sql.Types;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import javax.sql.DataSource;
+import org.apache.ignite.IgniteException;
+import org.apache.ignite.IgniteLogger;
+import org.apache.ignite.binary.BinaryObject;
+import org.apache.ignite.cache.CacheEntryVersion;
+import org.apache.ignite.cache.QueryEntity;
+import org.apache.ignite.cdc.CdcCacheEvent;
+import org.apache.ignite.cdc.CdcEvent;
+import org.apache.ignite.internal.util.typedef.F;
+
+import static 
org.apache.ignite.internal.processors.cache.GridCacheUtils.UNDEFINED_CACHE_ID;
+
+/** */
+public class IgniteToPostgreSqlCdcApplier {
+    /** */
+    public static final String DFLT_SQL_TYPE = "OTHER";
+
+    /** */
+    public static final Map<String, String> JAVA_TO_SQL_TYPES;
+
+    static {
+        Map<String, String> map = new HashMap<>();
+
+        map.put("java.lang.String", "VARCHAR");
+        map.put("java.lang.Integer", "INT");
+        map.put("int", "INT");
+        map.put("java.lang.Long", "BIGINT");
+        map.put("long", "BIGINT");
+        map.put("java.lang.Boolean", "BOOLEAN");
+        map.put("boolean", "BOOLEAN");
+        map.put("java.lang.Double", "DOUBLE PRECISION");
+        map.put("double", "DOUBLE PRECISION");
+        map.put("java.lang.Float", "REAL");
+        map.put("float", "REAL");
+        map.put("java.math.BigDecimal", "DECIMAL");
+        map.put("java.lang.Short", "SMALLINT");
+        map.put("short", "SMALLINT");
+        map.put("java.lang.Byte", "SMALLINT");
+        map.put("byte", "SMALLINT");
+        map.put("java.util.UUID", "UUID");
+        map.put("[B", "BYTEA");
+        map.put("java.lang.Object", "OTHER");
+
+        JAVA_TO_SQL_TYPES = Collections.unmodifiableMap(map);
+    }
+
+    /** */
+    private final DataSource dataSrc;
+
+    /** */
+    private final boolean autoCommit;
+
+    /** */
+    private final long maxBatchSize;
+
+    /** */
+    private final IgniteLogger log;
+
+    /** */
+    private final Map<Integer, String> cacheIdToUpsertQry = new HashMap<>();
+
+    /** */
+    private final Map<Integer, String> cacheIdToDeleteQry = new HashMap<>();
+
+    /** */
+    private final Map<Integer, Set<String>> cacheIdToPrimaryKeys = new 
HashMap<>();
+
+    /** */
+    private final Map<Integer, Set<String>> cacheIdToFields = new HashMap<>();
+
+    /** */
+    private final Set<Object> curKeys = new HashSet<>();
+
+    /**
+     * @param dataSrc {@link DataSource} - connection pool to PostgreSql
+     * @param autoCommit - autoCommit flag for batch execution
+     * @param maxBatchSize the maximum number of CDC events to include in a 
single batch
+     * @param log the {@link IgniteLogger} instance used for logging CDC 
processing events
+     */
+    public IgniteToPostgreSqlCdcApplier(DataSource dataSrc, boolean 
autoCommit, long maxBatchSize, IgniteLogger log) {
+        this.dataSrc = dataSrc;
+        this.autoCommit = autoCommit;
+        this.maxBatchSize = maxBatchSize;
+        this.log = log;
+    }
+
+    /**
+     * @param evts an {@link Iterator} of {@link CdcEvent} objects to be 
applied
+     * @return the total number of events successfully batched and executed
+     */
+    public long applyEvents(Iterator<CdcEvent> evts) {
+        try (Connection conn = dataSrc.getConnection()) {
+            conn.setAutoCommit(autoCommit);
+
+            long res = applyEvents(conn, evts);
+
+            conn.commit();
+
+            return res;
+        }
+        catch (Throwable e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException("CDC failure", e);
+        }
+    }
+
+    /**
+     * @param conn connection to PostgreSql
+     * @param evts an {@link Iterator} of {@link CdcEvent} objects to be 
applied
+     * @return the total number of events successfully batched and executed
+     */
+    private long applyEvents(Connection conn, Iterator<CdcEvent> evts) {
+        long evtsApplied = 0;
+
+        int currCacheId = UNDEFINED_CACHE_ID;
+        boolean prevOpIsDelete = false;
+        
+        PreparedStatement curPrepStmt = null;
+        CdcEvent evt;
+
+        while (evts.hasNext()) {
+            evt = evts.next();
+
+            if (log.isDebugEnabled())
+                log.debug("Event received [evt=" + evt + ']');
+
+            if (currCacheId != evt.cacheId() || prevOpIsDelete ^ (evt.value() 
== null)) {
+                if (curPrepStmt != null)
+                    evtsApplied += executeBatch(curPrepStmt);
+
+                currCacheId = evt.cacheId();
+                prevOpIsDelete = evt.value() == null;
+
+                curPrepStmt = prepareStatement(conn, evt);
+            }
+
+            if (curKeys.size() >= maxBatchSize || curKeys.contains(evt.key()))
+                evtsApplied += executeBatch(curPrepStmt);
+
+            addEvent(curPrepStmt, evt);
+        }
+
+        if (currCacheId != UNDEFINED_CACHE_ID)
+            evtsApplied += executeBatch(curPrepStmt);
+
+        return evtsApplied;
+    }
+
+    /**
+     * @param curPrepStmt {@link PreparedStatement}
+     * @return the total number of batches successfully executed. One CdcEvent 
- one batch.
+     */
+    private int executeBatch(PreparedStatement curPrepStmt) {
+        try {
+            curKeys.clear();
+
+            if (log.isDebugEnabled())
+                log.debug("Applying batch " + curPrepStmt.toString());
+
+            if (!curPrepStmt.isClosed())
+                return curPrepStmt.executeBatch().length;
+
+            throw new IgniteException("Tried to execute on closed prepared 
statement!");
+        }
+        catch (SQLException e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException(e);
+        }
+    }
+
+    /**
+     * @param conn connection to PostgreSql
+     * @param evt {@link CdcEvent}
+     * @return relevant {@link PreparedStatement}
+     */
+    private PreparedStatement prepareStatement(Connection conn, CdcEvent evt) {
+        String sqlQry;
+
+        if (evt.value() == null)
+            sqlQry = cacheIdToDeleteQry.get(evt.cacheId());
+        else
+            sqlQry = cacheIdToUpsertQry.get(evt.cacheId());
+
+        if (sqlQry == null)
+            throw new IgniteException("No SQL query is found for cacheId=" + 
evt.cacheId());
+
+        if (log.isDebugEnabled())
+            log.debug("Statement updated [cacheId=" + evt.cacheId() + ", 
sqlQry=" + sqlQry + ']');
+
+        try {
+            return conn.prepareStatement(sqlQry);
+        }
+        catch (SQLException e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException(e);
+        }
+    }
+
+    /**
+     * @param curPrepStmt {@link PreparedStatement}
+     * @param evt {@link CdcEvent}
+     */
+    private void addEvent(PreparedStatement curPrepStmt, CdcEvent evt) {
+        try {
+            if (evt.value() == null)
+                addEvent(curPrepStmt, evt, true);
+            else {
+                int idx = addEvent(curPrepStmt, evt, false);
+
+                curPrepStmt.setBytes(idx, encodeVersion(evt.version()));
+            }
+
+            curPrepStmt.addBatch();
+        }
+        catch (Throwable e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException(e);
+        }
+    }
+
+    /**
+     * @param curPrepStmt {@link PreparedStatement}
+     * @param evt {@link CdcEvent}
+     * @param isDelete - flag that indicate delete sql statement usage

Review Comment:
   remove "-"



##########
modules/cdc-ext/src/main/java/org/apache/ignite/cdc/postgresql/IgniteToPostgreSqlCdcApplier.java:
##########
@@ -0,0 +1,661 @@
+/*
+ * 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.cdc.postgresql;
+
+import java.math.BigDecimal;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.sql.Types;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import javax.sql.DataSource;
+import org.apache.ignite.IgniteException;
+import org.apache.ignite.IgniteLogger;
+import org.apache.ignite.binary.BinaryObject;
+import org.apache.ignite.cache.CacheEntryVersion;
+import org.apache.ignite.cache.QueryEntity;
+import org.apache.ignite.cdc.CdcCacheEvent;
+import org.apache.ignite.cdc.CdcEvent;
+import org.apache.ignite.internal.util.typedef.F;
+
+import static 
org.apache.ignite.internal.processors.cache.GridCacheUtils.UNDEFINED_CACHE_ID;
+
+/** */
+public class IgniteToPostgreSqlCdcApplier {
+    /** */
+    public static final String DFLT_SQL_TYPE = "OTHER";
+
+    /** */
+    public static final Map<String, String> JAVA_TO_SQL_TYPES;
+
+    static {
+        Map<String, String> map = new HashMap<>();
+
+        map.put("java.lang.String", "VARCHAR");
+        map.put("java.lang.Integer", "INT");
+        map.put("int", "INT");
+        map.put("java.lang.Long", "BIGINT");
+        map.put("long", "BIGINT");
+        map.put("java.lang.Boolean", "BOOLEAN");
+        map.put("boolean", "BOOLEAN");
+        map.put("java.lang.Double", "DOUBLE PRECISION");
+        map.put("double", "DOUBLE PRECISION");
+        map.put("java.lang.Float", "REAL");
+        map.put("float", "REAL");
+        map.put("java.math.BigDecimal", "DECIMAL");
+        map.put("java.lang.Short", "SMALLINT");
+        map.put("short", "SMALLINT");
+        map.put("java.lang.Byte", "SMALLINT");
+        map.put("byte", "SMALLINT");
+        map.put("java.util.UUID", "UUID");
+        map.put("[B", "BYTEA");
+        map.put("java.lang.Object", "OTHER");
+
+        JAVA_TO_SQL_TYPES = Collections.unmodifiableMap(map);
+    }
+
+    /** */
+    private final DataSource dataSrc;
+
+    /** */
+    private final boolean autoCommit;
+
+    /** */
+    private final long maxBatchSize;
+
+    /** */
+    private final IgniteLogger log;
+
+    /** */
+    private final Map<Integer, String> cacheIdToUpsertQry = new HashMap<>();
+
+    /** */
+    private final Map<Integer, String> cacheIdToDeleteQry = new HashMap<>();
+
+    /** */
+    private final Map<Integer, Set<String>> cacheIdToPrimaryKeys = new 
HashMap<>();
+
+    /** */
+    private final Map<Integer, Set<String>> cacheIdToFields = new HashMap<>();
+
+    /** */
+    private final Set<Object> curKeys = new HashSet<>();
+
+    /**
+     * @param dataSrc {@link DataSource} - connection pool to PostgreSql
+     * @param autoCommit - autoCommit flag for batch execution
+     * @param maxBatchSize the maximum number of CDC events to include in a 
single batch
+     * @param log the {@link IgniteLogger} instance used for logging CDC 
processing events
+     */
+    public IgniteToPostgreSqlCdcApplier(DataSource dataSrc, boolean 
autoCommit, long maxBatchSize, IgniteLogger log) {
+        this.dataSrc = dataSrc;
+        this.autoCommit = autoCommit;
+        this.maxBatchSize = maxBatchSize;
+        this.log = log;
+    }
+
+    /**
+     * @param evts an {@link Iterator} of {@link CdcEvent} objects to be 
applied
+     * @return the total number of events successfully batched and executed
+     */
+    public long applyEvents(Iterator<CdcEvent> evts) {
+        try (Connection conn = dataSrc.getConnection()) {
+            conn.setAutoCommit(autoCommit);
+
+            long res = applyEvents(conn, evts);
+
+            conn.commit();
+
+            return res;
+        }
+        catch (Throwable e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException("CDC failure", e);
+        }
+    }
+
+    /**
+     * @param conn connection to PostgreSql
+     * @param evts an {@link Iterator} of {@link CdcEvent} objects to be 
applied
+     * @return the total number of events successfully batched and executed
+     */
+    private long applyEvents(Connection conn, Iterator<CdcEvent> evts) {
+        long evtsApplied = 0;
+
+        int currCacheId = UNDEFINED_CACHE_ID;
+        boolean prevOpIsDelete = false;
+        
+        PreparedStatement curPrepStmt = null;
+        CdcEvent evt;
+
+        while (evts.hasNext()) {
+            evt = evts.next();
+
+            if (log.isDebugEnabled())
+                log.debug("Event received [evt=" + evt + ']');
+
+            if (currCacheId != evt.cacheId() || prevOpIsDelete ^ (evt.value() 
== null)) {
+                if (curPrepStmt != null)
+                    evtsApplied += executeBatch(curPrepStmt);
+
+                currCacheId = evt.cacheId();
+                prevOpIsDelete = evt.value() == null;
+
+                curPrepStmt = prepareStatement(conn, evt);
+            }
+
+            if (curKeys.size() >= maxBatchSize || curKeys.contains(evt.key()))
+                evtsApplied += executeBatch(curPrepStmt);
+
+            addEvent(curPrepStmt, evt);
+        }
+
+        if (currCacheId != UNDEFINED_CACHE_ID)
+            evtsApplied += executeBatch(curPrepStmt);
+
+        return evtsApplied;
+    }
+
+    /**
+     * @param curPrepStmt {@link PreparedStatement}
+     * @return the total number of batches successfully executed. One CdcEvent 
- one batch.
+     */
+    private int executeBatch(PreparedStatement curPrepStmt) {
+        try {
+            curKeys.clear();
+
+            if (log.isDebugEnabled())
+                log.debug("Applying batch " + curPrepStmt.toString());
+
+            if (!curPrepStmt.isClosed())
+                return curPrepStmt.executeBatch().length;
+
+            throw new IgniteException("Tried to execute on closed prepared 
statement!");
+        }
+        catch (SQLException e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException(e);
+        }
+    }
+
+    /**
+     * @param conn connection to PostgreSql
+     * @param evt {@link CdcEvent}
+     * @return relevant {@link PreparedStatement}
+     */
+    private PreparedStatement prepareStatement(Connection conn, CdcEvent evt) {
+        String sqlQry;
+
+        if (evt.value() == null)
+            sqlQry = cacheIdToDeleteQry.get(evt.cacheId());
+        else
+            sqlQry = cacheIdToUpsertQry.get(evt.cacheId());
+
+        if (sqlQry == null)
+            throw new IgniteException("No SQL query is found for cacheId=" + 
evt.cacheId());
+
+        if (log.isDebugEnabled())
+            log.debug("Statement updated [cacheId=" + evt.cacheId() + ", 
sqlQry=" + sqlQry + ']');
+
+        try {
+            return conn.prepareStatement(sqlQry);
+        }
+        catch (SQLException e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException(e);
+        }
+    }
+
+    /**
+     * @param curPrepStmt {@link PreparedStatement}
+     * @param evt {@link CdcEvent}
+     */
+    private void addEvent(PreparedStatement curPrepStmt, CdcEvent evt) {
+        try {
+            if (evt.value() == null)
+                addEvent(curPrepStmt, evt, true);
+            else {
+                int idx = addEvent(curPrepStmt, evt, false);
+
+                curPrepStmt.setBytes(idx, encodeVersion(evt.version()));

Review Comment:
   Looks like we can move it inside `addEvent`



##########
modules/cdc-ext/src/main/java/org/apache/ignite/cdc/postgresql/IgniteToPostgreSqlCdcApplier.java:
##########
@@ -0,0 +1,661 @@
+/*
+ * 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.cdc.postgresql;
+
+import java.math.BigDecimal;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.sql.Types;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import javax.sql.DataSource;
+import org.apache.ignite.IgniteException;
+import org.apache.ignite.IgniteLogger;
+import org.apache.ignite.binary.BinaryObject;
+import org.apache.ignite.cache.CacheEntryVersion;
+import org.apache.ignite.cache.QueryEntity;
+import org.apache.ignite.cdc.CdcCacheEvent;
+import org.apache.ignite.cdc.CdcEvent;
+import org.apache.ignite.internal.util.typedef.F;
+
+import static 
org.apache.ignite.internal.processors.cache.GridCacheUtils.UNDEFINED_CACHE_ID;
+
+/** */
+public class IgniteToPostgreSqlCdcApplier {
+    /** */
+    public static final String DFLT_SQL_TYPE = "OTHER";
+
+    /** */
+    public static final Map<String, String> JAVA_TO_SQL_TYPES;
+
+    static {
+        Map<String, String> map = new HashMap<>();
+
+        map.put("java.lang.String", "VARCHAR");
+        map.put("java.lang.Integer", "INT");
+        map.put("int", "INT");
+        map.put("java.lang.Long", "BIGINT");
+        map.put("long", "BIGINT");
+        map.put("java.lang.Boolean", "BOOLEAN");
+        map.put("boolean", "BOOLEAN");
+        map.put("java.lang.Double", "DOUBLE PRECISION");
+        map.put("double", "DOUBLE PRECISION");
+        map.put("java.lang.Float", "REAL");
+        map.put("float", "REAL");
+        map.put("java.math.BigDecimal", "DECIMAL");
+        map.put("java.lang.Short", "SMALLINT");
+        map.put("short", "SMALLINT");
+        map.put("java.lang.Byte", "SMALLINT");
+        map.put("byte", "SMALLINT");
+        map.put("java.util.UUID", "UUID");
+        map.put("[B", "BYTEA");
+        map.put("java.lang.Object", "OTHER");
+
+        JAVA_TO_SQL_TYPES = Collections.unmodifiableMap(map);
+    }
+
+    /** */
+    private final DataSource dataSrc;
+
+    /** */
+    private final boolean autoCommit;
+
+    /** */
+    private final long maxBatchSize;
+
+    /** */
+    private final IgniteLogger log;
+
+    /** */
+    private final Map<Integer, String> cacheIdToUpsertQry = new HashMap<>();
+
+    /** */
+    private final Map<Integer, String> cacheIdToDeleteQry = new HashMap<>();
+
+    /** */
+    private final Map<Integer, Set<String>> cacheIdToPrimaryKeys = new 
HashMap<>();
+
+    /** */
+    private final Map<Integer, Set<String>> cacheIdToFields = new HashMap<>();
+
+    /** */
+    private final Set<Object> curKeys = new HashSet<>();
+
+    /**
+     * @param dataSrc {@link DataSource} - connection pool to PostgreSql
+     * @param autoCommit - autoCommit flag for batch execution
+     * @param maxBatchSize the maximum number of CDC events to include in a 
single batch
+     * @param log the {@link IgniteLogger} instance used for logging CDC 
processing events
+     */
+    public IgniteToPostgreSqlCdcApplier(DataSource dataSrc, boolean 
autoCommit, long maxBatchSize, IgniteLogger log) {
+        this.dataSrc = dataSrc;
+        this.autoCommit = autoCommit;
+        this.maxBatchSize = maxBatchSize;
+        this.log = log;
+    }
+
+    /**
+     * @param evts an {@link Iterator} of {@link CdcEvent} objects to be 
applied
+     * @return the total number of events successfully batched and executed
+     */
+    public long applyEvents(Iterator<CdcEvent> evts) {
+        try (Connection conn = dataSrc.getConnection()) {
+            conn.setAutoCommit(autoCommit);
+
+            long res = applyEvents(conn, evts);
+
+            conn.commit();
+
+            return res;
+        }
+        catch (Throwable e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException("CDC failure", e);
+        }
+    }
+
+    /**
+     * @param conn connection to PostgreSql
+     * @param evts an {@link Iterator} of {@link CdcEvent} objects to be 
applied
+     * @return the total number of events successfully batched and executed
+     */
+    private long applyEvents(Connection conn, Iterator<CdcEvent> evts) {
+        long evtsApplied = 0;
+
+        int currCacheId = UNDEFINED_CACHE_ID;
+        boolean prevOpIsDelete = false;
+        
+        PreparedStatement curPrepStmt = null;
+        CdcEvent evt;
+
+        while (evts.hasNext()) {
+            evt = evts.next();
+
+            if (log.isDebugEnabled())
+                log.debug("Event received [evt=" + evt + ']');
+
+            if (currCacheId != evt.cacheId() || prevOpIsDelete ^ (evt.value() 
== null)) {
+                if (curPrepStmt != null)
+                    evtsApplied += executeBatch(curPrepStmt);
+
+                currCacheId = evt.cacheId();
+                prevOpIsDelete = evt.value() == null;
+
+                curPrepStmt = prepareStatement(conn, evt);
+            }
+
+            if (curKeys.size() >= maxBatchSize || curKeys.contains(evt.key()))
+                evtsApplied += executeBatch(curPrepStmt);
+
+            addEvent(curPrepStmt, evt);
+        }
+
+        if (currCacheId != UNDEFINED_CACHE_ID)
+            evtsApplied += executeBatch(curPrepStmt);
+
+        return evtsApplied;
+    }
+
+    /**
+     * @param curPrepStmt {@link PreparedStatement}
+     * @return the total number of batches successfully executed. One CdcEvent 
- one batch.
+     */
+    private int executeBatch(PreparedStatement curPrepStmt) {
+        try {
+            curKeys.clear();
+
+            if (log.isDebugEnabled())
+                log.debug("Applying batch " + curPrepStmt.toString());
+
+            if (!curPrepStmt.isClosed())
+                return curPrepStmt.executeBatch().length;
+
+            throw new IgniteException("Tried to execute on closed prepared 
statement!");
+        }
+        catch (SQLException e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException(e);
+        }
+    }
+
+    /**
+     * @param conn connection to PostgreSql
+     * @param evt {@link CdcEvent}
+     * @return relevant {@link PreparedStatement}
+     */
+    private PreparedStatement prepareStatement(Connection conn, CdcEvent evt) {
+        String sqlQry;
+
+        if (evt.value() == null)
+            sqlQry = cacheIdToDeleteQry.get(evt.cacheId());
+        else
+            sqlQry = cacheIdToUpsertQry.get(evt.cacheId());
+
+        if (sqlQry == null)
+            throw new IgniteException("No SQL query is found for cacheId=" + 
evt.cacheId());
+
+        if (log.isDebugEnabled())
+            log.debug("Statement updated [cacheId=" + evt.cacheId() + ", 
sqlQry=" + sqlQry + ']');
+
+        try {
+            return conn.prepareStatement(sqlQry);
+        }
+        catch (SQLException e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException(e);
+        }
+    }
+
+    /**
+     * @param curPrepStmt {@link PreparedStatement}
+     * @param evt {@link CdcEvent}
+     */
+    private void addEvent(PreparedStatement curPrepStmt, CdcEvent evt) {
+        try {
+            if (evt.value() == null)
+                addEvent(curPrepStmt, evt, true);
+            else {
+                int idx = addEvent(curPrepStmt, evt, false);
+
+                curPrepStmt.setBytes(idx, encodeVersion(evt.version()));
+            }
+
+            curPrepStmt.addBatch();
+        }
+        catch (Throwable e) {
+            log.error(e.getMessage(), e);
+
+            throw new IgniteException(e);
+        }
+    }
+
+    /**
+     * @param curPrepStmt {@link PreparedStatement}
+     * @param evt {@link CdcEvent}
+     * @param isDelete - flag that indicate delete sql statement usage
+     * @return number of filled values

Review Comment:
   number of filled fields?



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