环境信息： 我的集群中有两个Linux计算机（8U 16G 64位）节点。并且启用了Ignite本机持久性。 offHeap的内存为 3.2G 。 Ignite版本是2.6.0。
用法信息： 集群中有三个缓存，只有一个备份。总计约100,000条记录。 重新平衡线程数为1。
我的问题： 当我重复执行sql“ select *”时，发生错误“内存不足”。我用MAT分析了转储文件，发现一个线程消耗了太多内存。然后，我分析了线程堆栈，并在ignite方法org.apache.ignite.internal.processors.cache.IgniteCacheOffheapManagerImpl.rebalanceIterator中发现了一个treeMap，其成本接近 7G内存！ 有人可以帮我解决内存不足的问题吗？
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 | |
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
线索：使用以下代码创建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;
}
答案 0 :(得分：1)
看起来集群中同时存在重新平衡和select *个查询。
重新平衡是一个过程，该过程在节点之间移动分区以实现配置的备份因子。所有重新平衡的数据都通过堆，因此在此过程中可能会被污染。您可以在这里阅读有关内容：https://apacheignite.readme.io/docs/rebalancing
通过IgniteCache#rebalance()方法返回的日志中的相应消息或等待将来的消息可以跟踪重新平衡。
select *也是一项非常耗时的操作，因为它要求将所有数据都加载到单个节点上。
在这种情况下使用lazy查询可能会有所帮助。您可以在JDBC connection string或SqlFieldQuery#lazy属性中启用此标志。