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https://issues.apache.org/jira/browse/HBASE-2915?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12900916#action_12900916
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HBase Review Board commented on HBASE-2915:
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Message from: "Jean-Daniel Cryans" <[email protected]>
bq. On 2010-08-20 15:57:34, stack wrote:
bq. > /trunk/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java,
line 507
bq. > <http://review.cloudera.org/r/691/diff/1/?file=7612#file7612line507>
bq. >
bq. > I suppose this order is ok if the first thing we do on entrance to
HRegion is get the read lock before check of closing.
So I just redid that part. setClosing is first taken so that when the client
threads arrive they can fast fail by looking at closing.get before trying to
get the readLock.
bq. On 2010-08-20 15:57:34, stack wrote:
bq. > /trunk/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java,
line 712
bq. > <http://review.cloudera.org/r/691/diff/1/?file=7612#file7612line712>
bq. >
bq. > Seems like you could use your opentransaction/closetransaction
methods here and in flush too to be consistent?
Yeah the issue with compact and flush is that the callers don't expect to see
NSRE, the want null values.
bq. On 2010-08-20 15:57:34, stack wrote:
bq. > /trunk/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java,
line 1115
bq. > <http://review.cloudera.org/r/691/diff/1/?file=7612#file7612line1115>
bq. >
bq. > Aren't these lines unnecessary? openRegionTransaction does it?
Good catch.
bq. On 2010-08-20 15:57:34, stack wrote:
bq. > /trunk/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java,
line 3142
bq. > <http://review.cloudera.org/r/691/diff/1/?file=7612#file7612line3142>
bq. >
bq. > So, this javadoc is good but do you think we need some more doc?
Does there need to be more detail on new locking regime? Maybe there is no more
to be said that what is here in this paragraph. You've done all the work
unravelling our lock mess. With time your nice unravelling will rot unless its
clear what the pattern is. I'm just trying to think of ways of preventing
that happening.
Yeah I'll included some more javadoc, maybe with code examples?
- Jean-Daniel
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> Deadlock between HRegion.ICV and HRegion.close
> ----------------------------------------------
>
> Key: HBASE-2915
> URL: https://issues.apache.org/jira/browse/HBASE-2915
> Project: HBase
> Issue Type: Bug
> Reporter: Jean-Daniel Cryans
> Assignee: Jean-Daniel Cryans
> Priority: Blocker
> Fix For: 0.90.0
>
>
> HRegion.ICV gets a row lock then gets a newScanner lock.
> HRegion.close gets a newScanner lock, slitCloseLock and finally waits for all
> row locks to finish.
> If the ICV got the row lock and then close got the newScannerLock, both end
> up waiting on the other. This was introduced when Get became a Scan.
> Stack thinks we can get rid of the newScannerLock in close since we
> setClosing to true.
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