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https://issues.apache.org/jira/browse/IGNITE-9049?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16552150#comment-16552150
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ASF GitHub Bot commented on IGNITE-9049:
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GitHub user DmitriyGovorukhin opened a pull request:
https://github.com/apache/ignite/pull/4401
IGNITE-9049 fix write SWITCH_SEGMENT_RECORD in the end of file
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/gridgain/apache-ignite ignite-9049
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/ignite/pull/4401.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #4401
----
commit cdf86420885ddbf60bd6e4d452c913ef722a6d89
Author: Dmitriy Govorukhin <dmitriy.govorukhin@...>
Date: 2018-07-22T20:48:23Z
IGNITE-9049 fix write SWITCH_SEGMENT_RECORD in the end of file
----
> Missed SWITCH_SEGMENT_RECORD at the end of WAL file but space enough
> ---------------------------------------------------------------------
>
> Key: IGNITE-9049
> URL: https://issues.apache.org/jira/browse/IGNITE-9049
> Project: Ignite
> Issue Type: Improvement
> Components: persistence
> Reporter: Dmitriy Govorukhin
> Assignee: Dmitriy Govorukhin
> Priority: Major
> Fix For: 2.7
>
>
> There is a situation the several threads try addRecord when the free space
> ends (need rollOver to the next WAL segment) and none thread writes
> SWITCH_SEGMENT_RECORD. This leads to an end of the file will have garbage. If
> we try to iterate over this segment, iterator stopped when try to read next
> record and stumble on the garbage at the end of the file, it leads log will
> not be fully read. Any type of operation required iterator may be broken
> (crash recovery, delta rebalance, etc.).
> Example:
> File size 1024 bytes
> Current tail position 768 (free space 256)
> 1. Thread-1 try addRecord (size 128) -> tail update to 896.
> 2. Thread-2 try addRecord (size 128) -> tail update to 1024 (free space
> ended).
> None thread still not write any data, it just reserves position for write.
> (SegmentedRingByteBuffer.offer).
> 3. Thread-3 try addRecord (size 128) -> no space enough -> rollOver and CAS
> stop flag to TRUE.
> 4. Thread-1 and Thread-2 try to write data and cannot do it.
> FileWriteHandle.addRecord
> {code}
> if (buf == null || (stop.get() && rec.type() != SWITCH_SEGMENT_RECORD))
> return null; // Can not write to this segment,
> need to switch to the next one.
> {code}
> Thread-3 - can not write SWITCH_SEGMENT_RECORD because of not enough space.
> Thread-1 and Thread-2 cannot write their data because a stop is TRUE
> We have garbage from 768 to 1024 position.
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