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Posted to dev@hbase.apache.org by "Jean-Daniel Cryans (JIRA)" <ji...@apache.org> on 2010/01/11 19:28:54 UTC
[jira] Created: (HBASE-2105) All appends are serialized in HLog
All appends are serialized in HLog
----------------------------------
Key: HBASE-2105
URL: https://issues.apache.org/jira/browse/HBASE-2105
Project: Hadoop HBase
Issue Type: Bug
Affects Versions: 0.20.2
Reporter: Jean-Daniel Cryans
Assignee: Jean-Daniel Cryans
Priority: Blocker
Fix For: 0.21.0
duiod on IRC was asking about locks on the write path so I reviewed it a bit and saw that we are very good at not locking except on row level in HRegion and others but in HLog we actually synchronize everything on updateLock. I'm pretty sure that's not what we want. I guess a RWLock would be more useful.
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[jira] Commented: (HBASE-2105) All appends are serialized in HLog
Posted by "ryan rawson (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-2105?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12798812#action_12798812 ]
ryan rawson commented on HBASE-2105:
------------------------------------
I think the underlying sequence file is synchronized, so I'm not sure how much this would help...
> All appends are serialized in HLog
> ----------------------------------
>
> Key: HBASE-2105
> URL: https://issues.apache.org/jira/browse/HBASE-2105
> Project: Hadoop HBase
> Issue Type: Bug
> Affects Versions: 0.20.2
> Reporter: Jean-Daniel Cryans
> Assignee: Jean-Daniel Cryans
> Priority: Blocker
> Fix For: 0.20.4, 0.21.0
>
>
> duiod on IRC was asking about locks on the write path so I reviewed it a bit and saw that we are very good at not locking except on row level in HRegion and others but in HLog we actually synchronize everything on updateLock. I'm pretty sure that's not what we want. I guess a RWLock would be more useful.
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[jira] Updated: (HBASE-2105) All appends are serialized in HLog
Posted by "stack (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-2105?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
stack updated HBASE-2105:
-------------------------
Priority: Major (was: Blocker)
Fix Version/s: (was: 0.20.4)
(was: 0.21.0)
This is not a blocker, after discussion. Nor is it to be addressed in 0.20.4. Moving it out.
> All appends are serialized in HLog
> ----------------------------------
>
> Key: HBASE-2105
> URL: https://issues.apache.org/jira/browse/HBASE-2105
> Project: Hadoop HBase
> Issue Type: Bug
> Affects Versions: 0.20.2
> Reporter: Jean-Daniel Cryans
> Assignee: Jean-Daniel Cryans
>
> duiod on IRC was asking about locks on the write path so I reviewed it a bit and saw that we are very good at not locking except on row level in HRegion and others but in HLog we actually synchronize everything on updateLock. I'm pretty sure that's not what we want. I guess a RWLock would be more useful.
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[jira] Commented: (HBASE-2105) All appends are serialized in HLog
Posted by "stack (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-2105?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12798803#action_12798803 ]
stack commented on HBASE-2105:
------------------------------
I don't think there'll ever be a 0.20.4. Our focus has shifted to 0.21 hbase. I'd suggest that we get this into a 0.20.3 RC2. If it adds some speedup to server, it'd be a nice addition.
> All appends are serialized in HLog
> ----------------------------------
>
> Key: HBASE-2105
> URL: https://issues.apache.org/jira/browse/HBASE-2105
> Project: Hadoop HBase
> Issue Type: Bug
> Affects Versions: 0.20.2
> Reporter: Jean-Daniel Cryans
> Assignee: Jean-Daniel Cryans
> Priority: Blocker
> Fix For: 0.20.4, 0.21.0
>
>
> duiod on IRC was asking about locks on the write path so I reviewed it a bit and saw that we are very good at not locking except on row level in HRegion and others but in HLog we actually synchronize everything on updateLock. I'm pretty sure that's not what we want. I guess a RWLock would be more useful.
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[jira] Commented: (HBASE-2105) All appends are serialized in HLog
Posted by "stack (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-2105?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12798927#action_12798927 ]
stack commented on HBASE-2105:
------------------------------
Yeah, I was going to say what Ryan says, that down in SequenceFile, its synchronized anyway so we'd be narrowing the synchronization for sure but ain't sure the narrowing would make for that much in performance improvement.
Chatting too w/ J-D, we probably want the current synchronization to ensure that the get of the next sequence number happens in the same synchronization block that does the actual write. Otherwise, we could have edits going in out of order which could be a prob. if a high number edit goes in before a lower number edit.... we might lose a few edits if we crash after the high number goes in but before the lower edits have a chance to go in.
We might want to revisit if we want to run a pool of WAL-writers.
> All appends are serialized in HLog
> ----------------------------------
>
> Key: HBASE-2105
> URL: https://issues.apache.org/jira/browse/HBASE-2105
> Project: Hadoop HBase
> Issue Type: Bug
> Affects Versions: 0.20.2
> Reporter: Jean-Daniel Cryans
> Assignee: Jean-Daniel Cryans
> Priority: Blocker
> Fix For: 0.20.4, 0.21.0
>
>
> duiod on IRC was asking about locks on the write path so I reviewed it a bit and saw that we are very good at not locking except on row level in HRegion and others but in HLog we actually synchronize everything on updateLock. I'm pretty sure that's not what we want. I guess a RWLock would be more useful.
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[jira] Updated: (HBASE-2105) All appends are serialized in HLog
Posted by "Andrew Purtell (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-2105?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Andrew Purtell updated HBASE-2105:
----------------------------------
Fix Version/s: 0.20.4
Block branch too.
> All appends are serialized in HLog
> ----------------------------------
>
> Key: HBASE-2105
> URL: https://issues.apache.org/jira/browse/HBASE-2105
> Project: Hadoop HBase
> Issue Type: Bug
> Affects Versions: 0.20.2
> Reporter: Jean-Daniel Cryans
> Assignee: Jean-Daniel Cryans
> Priority: Blocker
> Fix For: 0.20.4, 0.21.0
>
>
> duiod on IRC was asking about locks on the write path so I reviewed it a bit and saw that we are very good at not locking except on row level in HRegion and others but in HLog we actually synchronize everything on updateLock. I'm pretty sure that's not what we want. I guess a RWLock would be more useful.
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