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https://issues.apache.org/jira/browse/DERBY-6398?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13813905#comment-13813905
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Knut Anders Hatlen commented on DERBY-6398:
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Thanks for that extra information, Marty. I'm afraid I still haven't been able
to reproduce it.
I'll summarize what I've figured out so far, in case that gives anyone ideas on
how to trigger it:
The hang happens in a code path that is followed only if auto-commit is
enabled. Furthermore, the call to FileLogger.flushAll() from
Xact.prepareCommit() seems to happen only if the previous commit on the same
transaction object was a non-synchronous commit. That is, a commit performed by
calling Xact.commitNoSync().
Most of the commitNoSync() calls seem to come in nested transactions, or in
transactions that happen in a background thread, so they would most likely not
use the same transaction object as the one used when auto-committing the
syscs_freeze_database() call. Exactly how this could happen, is still unclear
to me.
If this actually is what's causing the problem, a fix might be to do a
synchronous commit before freezing the database when in auto-commit mode.
Marty's observation that the hang can be avoided by updating a small record
before invoking the freeze command, is consistent with that theory.
> SYSCS_FREEZE_DATABASE locks-up if there are large records that haven't been
> flushed to the disk
> -----------------------------------------------------------------------------------------------
>
> Key: DERBY-6398
> URL: https://issues.apache.org/jira/browse/DERBY-6398
> Project: Derby
> Issue Type: Bug
> Components: Miscellaneous
> Affects Versions: 10.10.1.1
> Environment: Reliably demonstrated on Windows 7 with JDK 1.6.0_31
> Reporter: Marty Backe
> Fix For: 10.10.1.1
>
> Attachments: report.txt
>
>
> If after writing a record that contains a large data column (>100KB), the
> FREEZE command is issued, the command never returns (Derby appears to be
> dead-locked).
> E.g. sqlStatement.executeUpdate("CALL SYSCS_UTIL.SYSCS_FREEZE_DATABASE()");
> If the CALL SYSCS_UTIL.SYSCS_CHECKPOINT_DATABASE() command is first used
> before calling FREEZE, it does not lock-up.
> It's my opinion that calling FREEZE should never result in a dead-locked
> Derby instance.
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