為什么Apache Ignite sys-thread會消耗大量內存？

Question

環境信息：我的集群中有兩個Linux機器（8U 16G 64位）節點。 並且啟用了Ignite本機持久性。 offHeap的內存為3.2G 。 Ignite版本為2.6.0。

用法信息：集群中有三個緩存，只有一個備份。 總計約100,000條記錄。 重新平衡線程數為1。

我的問題：當我重復執行sql“ select *”時，出現錯誤“內存不足”。 我用MAT分析了轉儲文件，發現一個線程消耗了太多內存。 然后，我分析了線程堆棧，並發現在ignite方法org.apache.ignite.internal.processors.cache.IgniteCacheOffheapManagerImpl.rebalanceIterator中，創建了treeMap，其成本接近7G內存 ！ 有人可以幫助我解決內存不足的問題嗎？

 JVM options: -server -XX:MaxDirectMemorySize=512m -Xms10g -Xmx10g -XX:+AlwaysPreTouch -XX:+UseG1GC -XX:+AggressiveOpts -XX:+ScavengeBeforeFullGC -XX:+DisableExplicitGC -XX:+UseNUMA -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCDateStamps -XX:+PrintAdaptiveSizePolicy -XX:+UnlockDiagnosticVMOptions -XX:+G1PrintRegionLivenessInfo -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCApplicationConcurrentTime -XX:G1ReservePercent=15 -XX:InitiatingHeapOccupancyPercent=45 -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=10 -XX:GCLogFileSize=10M -XX:+HeapDumpOnOutOfMemoryError -XX:+ExitOnOutOfMemoryError 

 |Name | Shallow Heap | Retained Heap |Context Class Loader |Is Daemon ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- org.apache.ignite.thread.IgniteThread @ 0x5a0d32f20 |sys-#86%paloma2[172.17.0.1#192.154.163.17]%| 136 | 7,234,644,440 |org.springframework.boot.loader.LaunchedURLClassLoader @ 0x5a0ba53b8|false |- at java.lang.OutOfMemoryError.<init>()V (OutOfMemoryError.java:48) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.file.IgniteNativeIoLib.pread(ILcom/sun/jna/Pointer;Lcom/sun/jna/NativeLong;Lcom/sun/jna/NativeLong;)Lcom/sun/jna/NativeLong; (Native Method) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.file.AlignedBuffersDirectFileIO.readIntoAlignedBuffer(Ljava/nio/ByteBuffer;J)I (AlignedBuffersDirectFileIO.java:347) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.file.AlignedBuffersDirectFileIO.read(Ljava/nio/ByteBuffer;J)I (AlignedBuffersDirectFileIO.java:215) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.file.FilePageStore.read(JLjava/nio/ByteBuffer;Z)V (FilePageStore.java:351) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.file.FilePageStoreManager.read(IJLjava/nio/ByteBuffer;Z)V (FilePageStoreManager.java:328) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.file.FilePageStoreManager.read(IJLjava/nio/ByteBuffer;)V (FilePageStoreManager.java:312) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.pagemem.PageMemoryImpl.acquirePage(IJZ)J (PageMemoryImpl.java:779) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.pagemem.PageMemoryImpl.acquirePage(IJ)J (PageMemoryImpl.java:624) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.CacheDataRowAdapter.initFromLink(Lorg/apache/ignite/internal/processors/cache/CacheGroupContext;Lorg/apache/ignite/internal/processors/cache/GridCacheSharedContext;Lorg/apache/ignite/internal/pagemem/PageMemory;Lorg/apache/ignite/internal/processors/cache/persistence/CacheDataRowAdapter$RowData;)V (CacheDataRowAdapter.java:140)| | | | | |- at org.apache.ignite.internal.processors.cache.persistence.CacheDataRowAdapter.initFromLink(Lorg/apache/ignite/internal/processors/cache/CacheGroupContext;Lorg/apache/ignite/internal/processors/cache/persistence/CacheDataRowAdapter$RowData;)V (CacheDataRowAdapter.java:102) | | | | | |- at org.apache.ignite.internal.processors.cache.tree.DataRow.<init>(Lorg/apache/ignite/internal/processors/cache/CacheGroupContext;IJILorg/apache/ignite/internal/processors/cache/persistence/CacheDataRowAdapter$RowData;)V (DataRow.java:54) | | | | | |- at org.apache.ignite.internal.processors.cache.tree.CacheDataRowStore.dataRow(IIJLorg/apache/ignite/internal/processors/cache/persistence/CacheDataRowAdapter$RowData;)Lorg/apache/ignite/internal/processors/cache/persistence/CacheDataRow; (CacheDataRowStore.java:73) | | | | | |- at org.apache.ignite.internal.processors.cache.tree.CacheDataTree.getRow(Lorg/apache/ignite/internal/processors/cache/persistence/tree/io/BPlusIO;JILjava/lang/Object;)Lorg/apache/ignite/internal/processors/cache/persistence/CacheDataRow; (CacheDataTree.java:146) | | | | | |- at org.apache.ignite.internal.processors.cache.tree.CacheDataTree.getRow(Lorg/apache/ignite/internal/processors/cache/persistence/tree/io/BPlusIO;JILjava/lang/Object;)Ljava/lang/Object; (CacheDataTree.java:41) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree$ForwardCursor.fillFromBuffer(JLorg/apache/ignite/internal/processors/cache/persistence/tree/io/BPlusIO;II)Z (BPlusTree.java:4660) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree$ForwardCursor.init(JLorg/apache/ignite/internal/processors/cache/persistence/tree/io/BPlusIO;I)V (BPlusTree.java:4562) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree$ForwardCursor.access$5300(Lorg/apache/ignite/internal/processors/cache/persistence/tree/BPlusTree$ForwardCursor;JLorg/apache/ignite/internal/processors/cache/persistence/tree/io/BPlusIO;I)V (BPlusTree.java:4501) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree.findLowerUnbounded(Ljava/lang/Object;Ljava/lang/Object;)Lorg/apache/ignite/internal/util/lang/GridCursor; (BPlusTree.java:927) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree.find(Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;)Lorg/apache/ignite/internal/util/lang/GridCursor; (BPlusTree.java:959) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.tree.BPlusTree.find(Ljava/lang/Object;Ljava/lang/Object;)Lorg/apache/ignite/internal/util/lang/GridCursor; (BPlusTree.java:950) | | | | | |- at org.apache.ignite.internal.processors.cache.IgniteCacheOffheapManagerImpl$CacheDataStoreImpl.cursor()Lorg/apache/ignite/internal/util/lang/GridCursor; (IgniteCacheOffheapManagerImpl.java:1483) | | | | | |- at org.apache.ignite.internal.processors.cache.persistence.GridCacheOffheapManager$GridCacheDataStore.cursor()Lorg/apache/ignite/internal/util/lang/GridCursor; (GridCacheOffheapManager.java:1555) | | | | | |- at org.apache.ignite.internal.processors.cache.IgniteCacheOffheapManagerImpl.reservedIterator(ILorg/apache/ignite/internal/processors/affinity/AffinityTopologyVersion;)Lorg/apache/ignite/internal/util/lang/GridCloseableIterator; (IgniteCacheOffheapManagerImpl.java:839) | | | | | |- at org.apache.ignite.internal.processors.cache.IgniteCacheOffheapManagerImpl.rebalanceIterator(Lorg/apache/ignite/internal/processors/cache/distributed/dht/preloader/IgniteDhtDemandedPartitionsMap;Lorg/apache/ignite/internal/processors/affinity/AffinityTopologyVersion;)Lorg/apache/ignite/internal/processors/cache/IgniteRebalanceIterator; (IgniteCacheOffheapManagerImpl.java:882) | | | | | | |- <local> org.apache.ignite.internal.processors.cache.persistence.GridCacheOffheapManager @ 0x5a0d33368 | | 64 | 1,648 | | | |- <local> org.apache.ignite.internal.processors.cache.distributed.dht.preloader.IgniteDhtDemandedPartitionsMap @ 0x5a0d33408 | | 24 | 24 | | | |- <local> org.apache.ignite.internal.processors.affinity.AffinityTopologyVersion @ 0x5a0d33420 | | 24 | 24 | | | |- <local>java.util.TreeMap @ 0x5a0d33438 | | 48 | 7,227,513,912 | | | |- <local> java.util.HashSet @ 0x5a0d33468 | | 16 | 64 | | | |- <local> java.util.Collections$UnmodifiableCollection$1 @ 0x5a0d33478 | | 24 | 80 | | | |- <local> java.lang.Integer @ 0x5ad5cd658 354 | | 16 | 16 | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 

線索：使用以下代碼創建treeMap

  /** {@inheritDoc} */ @Override public IgniteRebalanceIterator rebalanceIterator(IgniteDhtDemandedPartitionsMap parts, final AffinityTopologyVersion topVer) throws IgniteCheckedException { final TreeMap<Integer, GridCloseableIterator<CacheDataRow>> iterators = new TreeMap<>(); Set<Integer> missing = new HashSet<>(); for (Integer p : parts.fullSet()) { GridCloseableIterator<CacheDataRow> partIter = reservedIterator(p, topVer); if (partIter == null) { missing.add(p); continue; } iterators.put(p, partIter); } IgniteHistoricalIterator historicalIterator = historicalIterator(parts.historicalMap(), missing); IgniteRebalanceIterator iter = new IgniteRebalanceIteratorImpl(iterators, historicalIterator); for (Integer p : missing) iter.setPartitionMissing(p); return iter; } 

Answer 1

似乎在集群中重新平衡並select *查詢並發運行。

重新平衡是一個過程，它在節點之間移動分區以實現配置的備份因子。 所有重新平衡的數據都通過堆，因此在此過程中可能會被污染。 您可以在此處閱讀有關內容： https : //apacheignite.readme.io/docs/rebalancing

從IgniteCache＃rebalance（）方法返回的日志中的相應消息或等待將來的相應消息可以跟蹤重新平衡 。

select *也是一項非常耗時的操作，因為它需要將所有數據加載到單個節點上。

在這種情況下，使用惰性查詢可能會有所幫助。 您可以在JDBC連接字符串中或作為SqlFieldQuery＃lazy屬性啟用此標志。