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From "Josh Elser (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PHOENIX-3111) Possible Deadlock/delay while building index, upsert select, delete rows at server
Date Thu, 14 Sep 2017 19:07:00 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-3111?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16166831#comment-16166831
] 

Josh Elser commented on PHOENIX-3111:
-------------------------------------

bq. My comment on it (ignored) was "This is crazy stuff with coprocessor taking out internal
region lock. It should have a test." So, I'd be up for removing it (smile);

bq. We have a hard enough time keeping out locking story straight in first place (see Andrew
Purtell comment too on the regime changing (too) often). I'm game for discussion.

Rajeshbabu just brought this one up to me this morning and I had the same reaction. This one
has my attention (for whatever that's worth).

> Possible Deadlock/delay while building index, upsert select, delete rows at server
> ----------------------------------------------------------------------------------
>
>                 Key: PHOENIX-3111
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-3111
>             Project: Phoenix
>          Issue Type: Bug
>            Reporter: Sergio Peleato
>            Assignee: Rajeshbabu Chintaguntla
>            Priority: Critical
>             Fix For: 4.8.0
>
>         Attachments: PHOENIX-3111_addendum.patch, PHOENIX-3111.patch, PHOENIX-3111_v2.patch
>
>
> There is a possible deadlock while building local index or running upsert select, delete
at server. The situation might happen in this case.
> In the above queries we scan mutations from table and write back to same table in that
case there is a chance of memstore might reach the threshold of blocking memstore size then
RegionTooBusyException might be thrown back to client and queries might retry scanning.
> Let's suppose if we take a local index build index case we first scan from the data table
and prepare index mutations and write back to same table.
> So there is chance of memstore full as well in that case we try to flush the region.
But if the split happen in between then split might be waiting for write lock on the region
to close and flush wait for readlock because the write lock in the queue until the local index
build completed. Local index build won't complete because we are not allowed to write until
there is flush. This might not be complete deadlock situation but the queries might take lot
of time to complete in this cases.
> {noformat}
> "regionserver//192.168.0.53:16201-splits-1469165876186" #269 prio=5 os_prio=31 tid=0x00007f7fb2050800
nid=0x1c033 waiting on condition [0x0000000139b68000]
>    java.lang.Thread.State: WAITING (parking)
>         at sun.misc.Unsafe.park(Native Method)
>         - parking to wait for  <0x00000006ede72550> (a java.util.concurrent.locks.ReentrantReadWriteLock$NonfairSync)
>         at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
>         at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836)
>         at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:870)
>         at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1199)
>         at java.util.concurrent.locks.ReentrantReadWriteLock$WriteLock.lock(ReentrantReadWriteLock.java:943)
>         at org.apache.hadoop.hbase.regionserver.HRegion.doClose(HRegion.java:1422)
>         at org.apache.hadoop.hbase.regionserver.HRegion.close(HRegion.java:1370)
>         - locked <0x00000006ede69d00> (a java.lang.Object)
>         at org.apache.hadoop.hbase.regionserver.SplitTransactionImpl.stepsBeforePONR(SplitTransactionImpl.java:394)
>         at org.apache.hadoop.hbase.regionserver.SplitTransactionImpl.createDaughters(SplitTransactionImpl.java:278)
>         at org.apache.hadoop.hbase.regionserver.SplitTransactionImpl.execute(SplitTransactionImpl.java:561)
>         at org.apache.hadoop.hbase.regionserver.SplitRequest.doSplitting(SplitRequest.java:82)
>         at org.apache.hadoop.hbase.regionserver.SplitRequest.run(SplitRequest.java:154)
>         at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
>         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
>         at java.lang.Thread.run(Thread.java:745)
>    Locked ownable synchronizers:
>         - <0x00000006ee132098> (a java.util.concurrent.ThreadPoolExecutor$Worker)
> {noformat}
> {noformat}
> "MemStoreFlusher.0" #170 prio=5 os_prio=31 tid=0x00007f7fb6842000 nid=0x19303 waiting
on condition [0x00000001388e9000]
>    java.lang.Thread.State: WAITING (parking)
>         at sun.misc.Unsafe.park(Native Method)
>         - parking to wait for  <0x00000006ede72550> (a java.util.concurrent.locks.ReentrantReadWriteLock$NonfairSync)
>         at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
>         at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836)
>         at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireShared(AbstractQueuedSynchronizer.java:967)
>         at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireShared(AbstractQueuedSynchronizer.java:1283)
>         at java.util.concurrent.locks.ReentrantReadWriteLock$ReadLock.lock(ReentrantReadWriteLock.java:727)
>         at org.apache.hadoop.hbase.regionserver.HRegion.flushcache(HRegion.java:1986)
>         at org.apache.hadoop.hbase.regionserver.HRegion.flush(HRegion.java:1950)
>         at org.apache.hadoop.hbase.regionserver.MemStoreFlusher.flushRegion(MemStoreFlusher.java:501)
>         at org.apache.hadoop.hbase.regionserver.MemStoreFlusher.flushRegion(MemStoreFlusher.java:471)
>         at org.apache.hadoop.hbase.regionserver.MemStoreFlusher.access$800(MemStoreFlusher.java:75)
>         at org.apache.hadoop.hbase.regionserver.MemStoreFlusher$FlushHandler.run(MemStoreFlusher.java:259)
>         at java.lang.Thread.run(Thread.java:745)
> {noformat}
> As a fix we need to block region splits if building index, upsert select, delete rows
running at server.
> Thanks [~sergey.soldatov] for the help in understanding the bug and analyzing it. [~speleato]
for finding it.



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