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From "stack (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HBASE-15392) Single Cell Get reads two HFileBlocks
Date Tue, 08 Mar 2016 20:15:41 GMT

     [ https://issues.apache.org/jira/browse/HBASE-15392?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

stack updated HBASE-15392:
--------------------------
    Attachment: 15392v4.patch

Patch with tests. Optimize seems broke to me. We keep SKIPping even though we've found all
our rows.

This patch does mostly the looksee of [~lhofhansl] except for the bit where someone specifies
a stopRow, in this case we try to avoid the load of next block.

In moreRowsMayExistAfter, check if a Get Scan. If so, return there are no more rows. If there
is a stopRow and it is not the EMPTY_END_ROW, then short-circuit the later checks that are
doing compares of stopRows.

In storeScanner optimize, rather than just check if it is a Get Scan -- as the looksee  patch
does -- instead we call moreRowsMayExistAfter. This means, IFF a stopRow has been specified,
we will do more compares (a compare in moreRowsMayExistAfter and then after we leave the optimize,
a call again to moreRowsMayExistAfter up in the StoreScanner#next).

I could drop the check for stopRow but what to do about stopRow overreading?

I've added three tests. The first verifies the simple case of a Get where all has the appearance
of being inside the same block. We verify that we indeed return after we find our column.

The second test is for what is broken, the case where the index says the next block starts
with a new row... the optimize was causing us to keep SKIPping till we hit the next row rather
than return after we had all our columns.

The third test is a test of optimize. I ask for the second column in a row of four columns.
There are four rows. If I fake out the StoreScanner rows start on block boundaries, I get
the below:

{code}
2016-03-08 12:14:41,734 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=1/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=2//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=INCLUDE_AND_SEEK_NEXT_ROW, after=INCLUDE
2016-03-08 12:14:41,737 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=1/cf:2/1/Put/vlen=1/seqid=0,
nextIndex=2//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=SEEK_NEXT_ROW, after=SKIP
2016-03-08 12:14:41,737 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=1/cf:3/1/Put/vlen=1/seqid=0,
nextIndex=2//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=SEEK_NEXT_ROW, after=SKIP
2016-03-08 12:14:41,737 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=1/cf:4/1/Put/vlen=1/seqid=0,
nextIndex=2//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=SEEK_NEXT_ROW, after=SKIP
2016-03-08 12:14:41,737 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=2/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=3//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=DONE, after=DONE
2016-03-08 12:14:41,737 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=2/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=3//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=INCLUDE_AND_SEEK_NEXT_ROW, after=INCLUDE
2016-03-08 12:14:41,738 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=2/cf:2/1/Put/vlen=1/seqid=0,
nextIndex=3//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=SEEK_NEXT_ROW, after=SKIP
2016-03-08 12:14:41,738 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=2/cf:3/1/Put/vlen=1/seqid=0,
nextIndex=3//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=SEEK_NEXT_ROW, after=SKIP
2016-03-08 12:14:41,738 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=2/cf:4/1/Put/vlen=1/seqid=0,
nextIndex=4//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=SEEK_NEXT_ROW, after=SKIP
2016-03-08 12:14:41,738 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=3/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=4//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=DONE, after=DONE
2016-03-08 12:14:41,738 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=3/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=4//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=INCLUDE_AND_SEEK_NEXT_ROW, after=INCLUDE
2016-03-08 12:14:41,738 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=3/cf:2/1/Put/vlen=1/seqid=0,
nextIndex=4//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=SEEK_NEXT_ROW, after=SKIP
2016-03-08 12:14:41,739 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=3/cf:3/1/Put/vlen=1/seqid=0,
nextIndex=4//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=SEEK_NEXT_ROW, after=SKIP
2016-03-08 12:14:41,739 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=3/cf:4/1/Put/vlen=1/seqid=0,
nextIndex=4//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=SEEK_NEXT_ROW, after=SKIP
2016-03-08 12:14:41,739 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=4/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=4//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=DONE, after=DONE
2016-03-08 12:14:41,739 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=4/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=4//LATEST_TIMESTAMP/Maximum/vlen=0/seqid=0, before=INCLUDE_AND_SEEK_NEXT_ROW, after=INCLUDE_AND_SEEK_NEXT_ROW
{code}

I was expecting more like this, what happens if there is no 'index' involved:

{code}
2016-03-08 12:12:54,020 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=1/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=, before=INCLUDE_AND_SEEK_NEXT_ROW, after=INCLUDE_AND_SEEK_NEXT_ROW
2016-03-08 12:12:54,024 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=2/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=, before=DONE, after=DONE
2016-03-08 12:12:54,024 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=2/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=, before=INCLUDE_AND_SEEK_NEXT_ROW, after=INCLUDE_AND_SEEK_NEXT_ROW
2016-03-08 12:12:54,024 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=3/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=, before=DONE, after=DONE
2016-03-08 12:12:54,024 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=3/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=, before=INCLUDE_AND_SEEK_NEXT_ROW, after=INCLUDE_AND_SEEK_NEXT_ROW
2016-03-08 12:12:54,025 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=4/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=, before=DONE, after=DONE
2016-03-08 12:12:54,025 INFO  [Time-limited test] regionserver.TestStoreScanner$1(137): Cell=4/cf:1/1/Put/vlen=1/seqid=0,
nextIndex=, before=INCLUDE_AND_SEEK_NEXT_ROW, after=INCLUDE_AND_SEEK_NEXT_ROW
{code}

If folks agree this 'broke', I'll work on getting some SEEK in there.

> Single Cell Get reads two HFileBlocks
> -------------------------------------
>
>                 Key: HBASE-15392
>                 URL: https://issues.apache.org/jira/browse/HBASE-15392
>             Project: HBase
>          Issue Type: Sub-task
>          Components: BucketCache
>            Reporter: stack
>            Assignee: stack
>         Attachments: 15392-0.98-looksee.txt, 15392.wip.patch, 15392v2.wip.patch, 15392v3.wip.patch,
15392v4.patch, HBASE-15392_suggest.patch, no_optimize.patch, no_optimize.patch, two_seeks.txt
>
>
> As found by Daniel "SystemTap" Pol, a simple Get results in our reading two HFileBlocks,
the one that contains the wanted Cell, and the block that follows.
> Here is a bit of custom logging that logs a stack trace on each HFileBlock read so you
can see the call stack responsible:
> {code}
> 2016-03-03 22:20:30,191 INFO  [B.defaultRpcServer.handler=20,queue=2,port=16020] regionserver.StoreScanner:
START LOOP
> 2016-03-03 22:20:30,192 INFO  [B.defaultRpcServer.handler=20,queue=2,port=16020] regionserver.StoreScanner:
QCODE SEEK_NEXT_COL
> 2016-03-03 22:20:30,192 INFO  [B.defaultRpcServer.handler=20,queue=2,port=16020] hfile.HFileBlockIndex:
STARTED WHILE
> 2016-03-03 22:20:30,192 INFO  [B.defaultRpcServer.handler=20,queue=2,port=16020] hfile.CombinedBlockCache:
OUT OF L2
> 2016-03-03 22:20:30,192 TRACE [B.defaultRpcServer.handler=20,queue=2,port=16020] bucket.BucketCache:
Read offset=31409152, len=2103
> 2016-03-03 22:20:30,192 TRACE [B.defaultRpcServer.handler=20,queue=2,port=16020] bucket.FileIOEngine:
offset=31409152, length=2103
> 2016-03-03 22:20:30,193 TRACE [B.defaultRpcServer.handler=20,queue=2,port=16020] hfile.HFileReaderImpl:
From Cache [blockType=DATA, fileOffset=2055421, headerSize=33, onDiskSizeWithoutHeader=2024,
uncompressedSizeWithoutHeader=2020, prevBlockOffset=2053364, isUseHBaseChecksum=true, checksumType=CRC32C,
bytesPerChecksum=16384, onDiskDataSizeWithHeader=2053, getOnDiskSizeWithHeader=2057, totalChecksumBytes=4,
isUnpacked=true, buf=[org.apache.hadoop.hbase.nio.SingleByteBuff@e19fbd54], dataBeginsWith=\x00\x00\x00)\x00\x00\x01`\x00\x16user995139035672819231,
fileContext=[usesHBaseChecksum=true, checksumType=CRC32C, bytesPerChecksum=16384, blocksize=65536,
encoding=NONE, includesMvcc=true, includesTags=false, compressAlgo=NONE, compressTags=false,
cryptoContext=[cipher=NONE keyHash=NONE]]]
> 2016-03-03 22:20:30,193 TRACE [B.defaultRpcServer.handler=20,queue=2,port=16020] hfile.HFileReaderImpl:
Cache hit return [blockType=DATA, fileOffset=2055421, headerSize=33, onDiskSizeWithoutHeader=2024,
uncompressedSizeWithoutHeader=2020, prevBlockOffset=2053364, isUseHBaseChecksum=true, checksumType=CRC32C,
bytesPerChecksum=16384, onDiskDataSizeWithHeader=2053, getOnDiskSizeWithHeader=2057, totalChecksumBytes=4,
isUnpacked=true, buf=[org.apache.hadoop.hbase.nio.SingleByteBuff@e19fbd54], dataBeginsWith=\x00\x00\x00)\x00\x00\x01`\x00\x16user995139035672819231,
fileContext=[usesHBaseChecksum=true, checksumType=CRC32C, bytesPerChecksum=16384, blocksize=65536,
encoding=NONE, includesMvcc=true, includesTags=false, compressAlgo=NONE, compressTags=false,
cryptoContext=[cipher=NONE keyHash=NONE]]]
> java.lang.Throwable
>         at org.apache.hadoop.hbase.io.hfile.HFileReaderImpl.readBlock(HFileReaderImpl.java:1515)
>         at org.apache.hadoop.hbase.io.hfile.HFileBlockIndex$CellBasedKeyBlockIndexReader.loadDataBlockWithScanInfo(HFileBlockIndex.java:324)
>         at org.apache.hadoop.hbase.io.hfile.HFileReaderImpl$HFileScannerImpl.seekTo(HFileReaderImpl.java:831)
>         at org.apache.hadoop.hbase.io.hfile.HFileReaderImpl$HFileScannerImpl.reseekTo(HFileReaderImpl.java:812)
>         at org.apache.hadoop.hbase.regionserver.StoreFileScanner.reseekAtOrAfter(StoreFileScanner.java:288)
>         at org.apache.hadoop.hbase.regionserver.StoreFileScanner.reseek(StoreFileScanner.java:198)
>         at org.apache.hadoop.hbase.regionserver.NonLazyKeyValueScanner.doRealSeek(NonLazyKeyValueScanner.java:54)
>         at org.apache.hadoop.hbase.regionserver.KeyValueHeap.generalizedSeek(KeyValueHeap.java:321)
>         at org.apache.hadoop.hbase.regionserver.KeyValueHeap.requestSeek(KeyValueHeap.java:279)
>         at org.apache.hadoop.hbase.regionserver.StoreScanner.reseek(StoreScanner.java:806)
>         at org.apache.hadoop.hbase.regionserver.StoreScanner.seekAsDirection(StoreScanner.java:795)
>         at org.apache.hadoop.hbase.regionserver.StoreScanner.next(StoreScanner.java:624)
>         at org.apache.hadoop.hbase.regionserver.KeyValueHeap.next(KeyValueHeap.java:153)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.populateResult(HRegion.java:5703)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.nextInternal(HRegion.java:5849)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.nextRaw(HRegion.java:5622)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.next(HRegion.java:5598)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.next(HRegion.java:5584)
>         at org.apache.hadoop.hbase.regionserver.RSRpcServices.get(RSRpcServices.java:2187)
>         at org.apache.hadoop.hbase.regionserver.RSRpcServices.get(RSRpcServices.java:2123)
>         at org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$2.callBlockingMethod(ClientProtos.java:33512)
>         at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2229)
>         at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:109)
>         at org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:136)
>         at org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:111)
>         at java.lang.Thread.run(Thread.java:745)
> 2016-03-03 22:20:30,193 INFO  [B.defaultRpcServer.handler=20,queue=2,port=16020] hfile.HFileBlockIndex:
READ [blockType=DATA, fileOffset=2055421, headerSize=33, onDiskSizeWithoutHeader=2024, uncompressedSizeWithoutHeader=2020,
prevBlockOffset=2053364, isUseHBaseChecksum=true, checksumType=CRC32C, bytesPerChecksum=16384,
onDiskDataSizeWithHeader=2053, getOnDiskSizeWithHeader=2057, totalChecksumBytes=4, isUnpacked=true,
buf=[org.apache.hadoop.hbase.nio.SingleByteBuff@e19fbd54], dataBeginsWith=\x00\x00\x00)\x00\x00\x01`\x00\x16user995139035672819231,
fileContext=[usesHBaseChecksum=true, checksumType=CRC32C, bytesPerChecksum=16384, blocksize=65536,
encoding=NONE, includesMvcc=true, includesTags=false, compressAlgo=NONE, compressTags=false,
cryptoContext=[cipher=NONE keyHash=NONE]]]
> 2016-03-03 22:20:30,193 INFO  [B.defaultRpcServer.handler=20,queue=2,port=16020] hfile.HFileBlockIndex:
DATA BLOCK IS TRUE BREAK
> 2016-03-03 22:20:30,193 INFO  [B.defaultRpcServer.handler=20,queue=2,port=16020] hfile.HFileBlockIndex:
RETURNING
> 2016-03-03 22:20:30,194 INFO  [B.defaultRpcServer.handler=20,queue=2,port=16020] regionserver.StoreScanner:
QCODE INCLUDE
> 2016-03-03 22:20:30,194 INFO  [B.defaultRpcServer.handler=20,queue=2,port=16020] regionserver.StoreScanner:
QCODE SKIP
> 2016-03-03 22:20:30,194 INFO  [B.defaultRpcServer.handler=20,queue=2,port=16020] hfile.CombinedBlockCache:
OUT OF L2
> 2016-03-03 22:20:30,194 TRACE [B.defaultRpcServer.handler=20,queue=2,port=16020] bucket.BucketCache:
Read offset=30932992, len=2103
> 2016-03-03 22:20:30,194 TRACE [B.defaultRpcServer.handler=20,queue=2,port=16020] bucket.FileIOEngine:
offset=30932992, length=2103
> 2016-03-03 22:20:30,194 TRACE [B.defaultRpcServer.handler=20,queue=2,port=16020] hfile.HFileReaderImpl:
From Cache [blockType=DATA, fileOffset=2057478, headerSize=33, onDiskSizeWithoutHeader=2024,
uncompressedSizeWithoutHeader=2020, prevBlockOffset=2055421, isUseHBaseChecksum=true, checksumType=CRC32C,
bytesPerChecksum=16384, onDiskDataSizeWithHeader=2053, getOnDiskSizeWithHeader=2057, totalChecksumBytes=4,
isUnpacked=true, buf=[org.apache.hadoop.hbase.nio.SingleByteBuff@6063ac95], dataBeginsWith=\x00\x00\x00)\x00\x00\x01`\x00\x16user995698996184959679,
fileContext=[usesHBaseChecksum=true, checksumType=CRC32C, bytesPerChecksum=16384, blocksize=65536,
encoding=NONE, includesMvcc=true, includesTags=false, compressAlgo=NONE, compressTags=false,
cryptoContext=[cipher=NONE keyHash=NONE]]]
> 2016-03-03 22:20:30,194 TRACE [B.defaultRpcServer.handler=20,queue=2,port=16020] hfile.HFileReaderImpl:
Cache hit return [blockType=DATA, fileOffset=2057478, headerSize=33, onDiskSizeWithoutHeader=2024,
uncompressedSizeWithoutHeader=2020, prevBlockOffset=2055421, isUseHBaseChecksum=true, checksumType=CRC32C,
bytesPerChecksum=16384, onDiskDataSizeWithHeader=2053, getOnDiskSizeWithHeader=2057, totalChecksumBytes=4,
isUnpacked=true, buf=[org.apache.hadoop.hbase.nio.SingleByteBuff@6063ac95], dataBeginsWith=\x00\x00\x00)\x00\x00\x01`\x00\x16user995698996184959679,
fileContext=[usesHBaseChecksum=true, checksumType=CRC32C, bytesPerChecksum=16384, blocksize=65536,
encoding=NONE, includesMvcc=true, includesTags=false, compressAlgo=NONE, compressTags=false,
cryptoContext=[cipher=NONE keyHash=NONE]]]
> java.lang.Throwable
>         at org.apache.hadoop.hbase.io.hfile.HFileReaderImpl.readBlock(HFileReaderImpl.java:1515)
>         at org.apache.hadoop.hbase.io.hfile.HFileReaderImpl$HFileScannerImpl.readNextDataBlock(HFileReaderImpl.java:906)
>         at org.apache.hadoop.hbase.io.hfile.HFileReaderImpl$HFileScannerImpl.isNextBlock(HFileReaderImpl.java:1106)
>         at org.apache.hadoop.hbase.io.hfile.HFileReaderImpl$HFileScannerImpl.positionForNextBlock(HFileReaderImpl.java:1100)
>         at org.apache.hadoop.hbase.io.hfile.HFileReaderImpl$HFileScannerImpl._next(HFileReaderImpl.java:1118)
>         at org.apache.hadoop.hbase.io.hfile.HFileReaderImpl$HFileScannerImpl.next(HFileReaderImpl.java:1139)
>         at org.apache.hadoop.hbase.regionserver.StoreFileScanner.next(StoreFileScanner.java:152)
>         at org.apache.hadoop.hbase.regionserver.KeyValueHeap.next(KeyValueHeap.java:114)
>         at org.apache.hadoop.hbase.regionserver.StoreScanner.next(StoreScanner.java:628)
>         at org.apache.hadoop.hbase.regionserver.KeyValueHeap.next(KeyValueHeap.java:153)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.populateResult(HRegion.java:5703)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.nextInternal(HRegion.java:5849)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.nextRaw(HRegion.java:5622)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.next(HRegion.java:5598)
>         at org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.next(HRegion.java:5584)
>         at org.apache.hadoop.hbase.regionserver.RSRpcServices.get(RSRpcServices.java:2187)
>         at org.apache.hadoop.hbase.regionserver.RSRpcServices.get(RSRpcServices.java:2123)
>         at org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$2.callBlockingMethod(ClientProtos.java:33512)
>         at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2229)
>         at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:109)
>         at org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:136)
>         at org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:111)
>         at java.lang.Thread.run(Thread.java:745)
> 2016-03-03 22:20:30,195 INFO  [B.defaultRpcServer.handler=20,queue=2,port=16020] regionserver.StoreScanner:
QCODE DONE
> {code}
> We are in StoreScanner#next.
> Matcher does SEEK_NEXT_COL.
> We pull in the block that has our Cell in it.
> Matcher does INCLUDE
> Then Matcher does SKIP
> SKIP has us go read the next block.
> Then Matcher does DONE.
> Why ain't I getting to DONE after INCLUDE?
> Any clues?
> This code has been like this a while.



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