[
https://issues.apache.org/jira/browse/HBASE-14178?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14650729#comment-14650729
]
Duo Zhang commented on HBASE-14178:
-----------------------------------
I think the problem here is we only allow one thread read a HFileBlock at the
same time even if we disable the BlockCache.
If BlockCache is enabled, this is useful since other threads can get the block
directly from BlockCache after one thread successfully read the block and put
it into BlockCache.
This is a needless overhead if we disable BlockCache although I think one
should always turn on BlockCache if there are many requests to the same
HFileBlock. We should just read the HFileBlock from HDFS.
[~chenheng], could you please prepare a patch for master first? Thanks.
> regionserver blocks because of waiting for offsetLock
> -----------------------------------------------------
>
> Key: HBASE-14178
> URL: https://issues.apache.org/jira/browse/HBASE-14178
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 0.98.6
> Reporter: Heng Chen
> Priority: Critical
> Fix For: 0.98.6
>
> Attachments: HBASE-14178-0.98.patch, jstack
>
>
> My regionserver blocks, and all client rpc timeout.
> I print the regionserver's jstack, it seems a lot of thread was blocked for
> waiting offsetLock, detail infomation belows:
> PS: my table's block cache is off
> {code}
> "B.DefaultRpcServer.handler=2,queue=2,port=60020" #82 daemon prio=5 os_prio=0
> tid=0x0000000001827000 nid=0x2cdc in Object.wait() [0x00007f3831b72000]
> java.lang.Thread.State: WAITING (on object monitor)
> at java.lang.Object.wait(Native Method)
> at java.lang.Object.wait(Object.java:502)
> at org.apache.hadoop.hbase.util.IdLock.getLockEntry(IdLock.java:79)
> - locked <0x0000000773af7c18> (a
> org.apache.hadoop.hbase.util.IdLock$Entry)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderV2.readBlock(HFileReaderV2.java:352)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlockIndex$BlockIndexReader.loadDataBlockWithScanInfo(HFileBlockIndex.java:253)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderV2$AbstractScannerV2.seekTo(HFileReaderV2.java:524)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderV2$AbstractScannerV2.reseekTo(HFileReaderV2.java:572)
> at
> org.apache.hadoop.hbase.regionserver.StoreFileScanner.reseekAtOrAfter(StoreFileScanner.java:257)
> at
> org.apache.hadoop.hbase.regionserver.StoreFileScanner.reseek(StoreFileScanner.java:173)
> at
> org.apache.hadoop.hbase.regionserver.NonLazyKeyValueScanner.doRealSeek(NonLazyKeyValueScanner.java:55)
> at
> org.apache.hadoop.hbase.regionserver.KeyValueHeap.generalizedSeek(KeyValueHeap.java:313)
> at
> org.apache.hadoop.hbase.regionserver.KeyValueHeap.requestSeek(KeyValueHeap.java:269)
> at
> org.apache.hadoop.hbase.regionserver.StoreScanner.reseek(StoreScanner.java:695)
> at
> org.apache.hadoop.hbase.regionserver.StoreScanner.seekAsDirection(StoreScanner.java:683)
> at
> org.apache.hadoop.hbase.regionserver.StoreScanner.next(StoreScanner.java:533)
> at
> org.apache.hadoop.hbase.regionserver.KeyValueHeap.next(KeyValueHeap.java:140)
> at
> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.populateResult(HRegion.java:3889)
> at
> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.nextInternal(HRegion.java:3969)
> at
> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.nextRaw(HRegion.java:3847)
> at
> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.next(HRegion.java:3820)
> - locked <0x00000005e5c55ad0> (a
> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl)
> at
> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.next(HRegion.java:3807)
> at org.apache.hadoop.hbase.regionserver.HRegion.get(HRegion.java:4779)
> at org.apache.hadoop.hbase.regionserver.HRegion.get(HRegion.java:4753)
> at
> org.apache.hadoop.hbase.regionserver.HRegionServer.get(HRegionServer.java:2916)
> at
> org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$2.callBlockingMethod(ClientProtos.java:29583)
> at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2027)
> at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:108)
> at
> org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:114)
> at org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:94)
> at java.lang.Thread.run(Thread.java:745)
> Locked ownable synchronizers:
> - <0x00000005e5c55c08> (a
> java.util.concurrent.locks.ReentrantLock$NonfairSync)
> {code}
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
