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https://issues.apache.org/jira/browse/IGNITE-15959?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17570958#comment-17570958
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Denis Chudov commented on IGNITE-15959:
---------------------------------------
The problem is that CacheDataTree fetches the value by the link from the
partition, to pass it to AtomicCacheUpdateClosure, but its unclear if this
value is actually necessary for this closure to remove the entry. For
transactional caches the reproducer also works but OOM happens on the phase
when tx entries are enlisted. There is an option for CacheDataTree#invoke to
fetch the row with only link without data, if the entry was found:
CacheDataRowAdapter.RowData#LINK_ONLY. The further investigation needed if it
is acceptable to not pass a value to update closures which are intended to
remove the entry.
> Remove operation fetches entry value into heap
> ----------------------------------------------
>
> Key: IGNITE-15959
> URL: https://issues.apache.org/jira/browse/IGNITE-15959
> Project: Ignite
> Issue Type: Improvement
> Affects Versions: 2.11
> Reporter: Alexey Kukushkin
> Priority: Major
> Labels: cggg
> Original Estimate: 40h
> Remaining Estimate: 40h
>
> [See similar problem for the containsKey()
> operation|https://issues.apache.org/jira/browse/IGNITE-16137]
> {{IgniteCache#remove(key)}} operation fetches full entry into heap memory.
> This is inefficient when working with large objects: our application running
> with limited heap memory fails with {{java.lang.OutOfMemoryError: Java heap
> space}} when trying to remove an entry by key.
> It seems wrong that Ignite needs to fetch the full entry on heap to remove
> the entry. Please enhance Ignite to not be doing that or explain why Ignite
> must do that.
> h2. Reproducer
> h3. Steps
> Create a Gradle project with the below class and run it as
> {{./gradlew test --tests apache.ignite.issues.RemoveOperationHeapUsage}}
> {{build.gradle}}
> {code:groovy}
> test {
> minHeapSize = "512m"
> maxHeapSize = "512m"
> }
> {code}
> {{RemoveOperationHeapUsage.java}}
> {code:java}
> public class RemoveOperationHeapUsage {
> /** Run the test with -Xmx512m -Xms512m */
> @Test
> public void removeOperationFetchesValueOnHeap() {
> var igniteCfg = new IgniteConfiguration()
> .setDiscoverySpi(
> new TcpDiscoverySpi()
> .setIpFinder(new
> TcpDiscoveryVmIpFinder().setAddresses(Collections.singleton("127.0.0.1:47500")))
> )
> .setCacheConfiguration(new CacheConfiguration<>("blobs"));
> try (var ignite = Ignition.start(igniteCfg)) {
> Cache<Integer, byte[]> cache = ignite.cache("blobs");
> // Put a BLOB having size of 35% of free memory to the cache
> Runtime.getRuntime().gc();
> var freeMemory = Runtime.getRuntime().freeMemory();
> var blobSize = (int)(freeMemory * 0.35);
> putBlob(cache, blobSize);
> // Use 70% of the free heap
> Runtime.getRuntime().gc();
> var unused = new byte[2 * blobSize];
> // Remove the blob from the cache.
> // This throws "OutOfMemoryError: Java heap space" since Ignite
> retrieves full entry to the heap.
> // Why does Ignite retrieve entry value to delete the entry?
> cache.remove(1);
> }
> }
> private static void putBlob(Cache<Integer, byte[]> cache, int blobSize) {
> var blob = new byte[blobSize];
> cache.put(1, blob);
> }
> }
> {code}
> h3. Expected
> The test passes
> h3. Actual
> The {{cache.remove}} operatoin fails with:
> {noformat}
> java.lang.OutOfMemoryError: Java heap space
> at
> org.apache.ignite.internal.processors.cache.IncompleteCacheObject.<init>(IncompleteCacheObject.java:44)
> at
> org.apache.ignite.internal.processors.cache.binary.CacheObjectBinaryProcessorImpl.toCacheObject(CacheObjectBinaryProcessorImpl.java:1385)
> at
> org.apache.ignite.internal.processors.cache.persistence.CacheDataRowAdapter.readIncompleteValue(CacheDataRowAdapter.java:680)
> at
> org.apache.ignite.internal.processors.cache.persistence.CacheDataRowAdapter.readFragment(CacheDataRowAdapter.java:500)
> at
> org.apache.ignite.internal.processors.cache.persistence.CacheDataRowAdapter.readIncomplete(CacheDataRowAdapter.java:411)
> at
> org.apache.ignite.internal.processors.cache.persistence.CacheDataRowAdapter.doInitFromLink(CacheDataRowAdapter.java:316)
> at
> org.apache.ignite.internal.processors.cache.persistence.CacheDataRowAdapter.initFromLink(CacheDataRowAdapter.java:165)
> at
> org.apache.ignite.internal.processors.cache.persistence.CacheDataRowAdapter.initFromLink(CacheDataRowAdapter.java:136)
> at
> org.apache.ignite.internal.processors.cache.tree.DataRow.<init>(DataRow.java:55)
> at
> org.apache.ignite.internal.processors.cache.tree.CacheDataRowStore.dataRow(CacheDataRowStore.java:129)
> at
> org.apache.ignite.internal.processors.cache.tree.CacheDataTree.getRow(CacheDataTree.java:422)
> at
> org.apache.ignite.internal.processors.cache.tree.CacheDataTree.getRow(CacheDataTree.java:63)
> at
> org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree$Invoke.found(BPlusTree.java:3987)
> at
> org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree$Search.run0(BPlusTree.java:317)
> at
> org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree$GetPageHandler.run(BPlusTree.java:5921)
> at
> org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree$Search.run(BPlusTree.java:290)
> at
> org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree$GetPageHandler.run(BPlusTree.java:5907)
> at
> org.apache.ignite.internal.processors.cache.persistence.tree.util.PageHandler.readPage(PageHandler.java:174)
> at
> org.apache.ignite.internal.processors.cache.persistence.DataStructure.read(DataStructure.java:397)
> at
> org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree.read(BPlusTree.java:6108)
> at
> org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree.invokeDown(BPlusTree.java:1991)
> at
> org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree.invoke(BPlusTree.java:1920)
> at
> org.apache.ignite.internal.processors.cache.IgniteCacheOffheapManagerImpl$CacheDataStoreImpl.invoke0(IgniteCacheOffheapManagerImpl.java:1765)
> at
> org.apache.ignite.internal.processors.cache.IgniteCacheOffheapManagerImpl$CacheDataStoreImpl.invoke(IgniteCacheOffheapManagerImpl.java:1748)
> at
> org.apache.ignite.internal.processors.cache.IgniteCacheOffheapManagerImpl.invoke(IgniteCacheOffheapManagerImpl.java:441)
> at
> org.apache.ignite.internal.processors.cache.GridCacheMapEntry.innerUpdate(GridCacheMapEntry.java:2342)
> at
> org.apache.ignite.internal.processors.cache.distributed.dht.atomic.GridDhtAtomicCache.updateSingle(GridDhtAtomicCache.java:2589)
> at
> org.apache.ignite.internal.processors.cache.distributed.dht.atomic.GridDhtAtomicCache.update(GridDhtAtomicCache.java:2049)
> at
> org.apache.ignite.internal.processors.cache.distributed.dht.atomic.GridDhtAtomicCache.updateAllAsyncInternal0(GridDhtAtomicCache.java:1866)
> at
> org.apache.ignite.internal.processors.cache.distributed.dht.atomic.GridDhtAtomicCache.updateAllAsyncInternal(GridDhtAtomicCache.java:1725)
> at
> org.apache.ignite.internal.processors.cache.distributed.dht.atomic.GridNearAtomicAbstractUpdateFuture.sendSingleRequest(GridNearAtomicAbstractUpdateFuture.java:306)
> at
> org.apache.ignite.internal.processors.cache.distributed.dht.atomic.GridNearAtomicSingleUpdateFuture.map(GridNearAtomicSingleUpdateFuture.java:487)
> {noformat}
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