[jira] [Issue Comment Deleted] (ZOOKEEPER-2574) PurgeTxnLog can inadvertently delete required txn log files

["Patrick Hunt (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ZOOKEEPER-2574?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Patrick Hunt updated ZOOKEEPER-2574:
------------------------------------
    Comment: was deleted

(was: +1 overall.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12827931/ZOOKEEPER-2574.3.patch
  against trunk revision 8c4082647f89b0a92fa00a2af8de84b3c7314e23.

    +1 @author.  The patch does not contain any @author tags.

    +1 tests included.  The patch appears to include 3 new or modified tests.

    +1 javadoc.  The javadoc tool did not generate any warning messages.

    +1 javac.  The applied patch does not increase the total number of javac compiler warnings.

    +1 findbugs.  The patch does not introduce any new Findbugs (version 2.0.3) warnings.

    +1 release audit.  The applied patch does not increase the total number of release audit warnings.

    +1 core tests.  The patch passed core unit tests.

    +1 contrib tests.  The patch passed contrib unit tests.

Test results: https://builds.apache.org/job/PreCommit-ZOOKEEPER-Build/3416//testReport/
Findbugs warnings: https://builds.apache.org/job/PreCommit-ZOOKEEPER-Build/3416//artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html
Console output: https://builds.apache.org/job/PreCommit-ZOOKEEPER-Build/3416//console

This message is automatically generated.)

> PurgeTxnLog can inadvertently delete required txn log files
> -----------------------------------------------------------
>
>                 Key: ZOOKEEPER-2574
>                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2574
>             Project: ZooKeeper
>          Issue Type: Bug
>          Components: server
>    Affects Versions: 3.4.7, 3.4.8, 3.5.0, 3.5.1, 3.5.2
>         Environment: Zookeeper 3.4.8, standalone, and 3-server quorum
>            Reporter: Abhishek Rai
>            Assignee: Abhishek Rai
>            Priority: Blocker
>             Fix For: 3.4.10, 3.5.3
>
>         Attachments: ZOOKEEPER-2574.2.patch, ZOOKEEPER-2574.3.patch, ZOOKEEPER-2574.patch
>
>
> As part of the fix for ZOOKEEPER-1797, the call to FileTxnSnapLog.getSnapshotLogs() was removed from PurgeTxnLog.java.  As a result, some old-looking but required txn log files can be deleted, resulting in data corruption or loss.
> For example, consider the following:
> 1. Configuration:
> autopurge.snapRetainCount=3
> 2. Following files exist:
> log.100 spans transactions from zxid=100 till zxid=140 (inclusive)
> snapshot.110 - snapshot as of zxid=110
> snapshot.120 - snapshot as of zxid=120
> snapshot.130 - snapshot as of zxid=130
> Above scenario is possible when snapshotting has happened multiple times but without accompanying log rollover, which is possible if the server was running as a learner.
> 3. PurgeTxnLog retains all snapshots but deletes log.100 because its zxid is older than the zxid of the oldest snapshot (110).  This results in loss of transactions in the range 131-140.
> Before the fix for ZOOKEEPER-1797, this was avoided by the call to FileTxnSnapLog.getSnapshotLogs() which finds and retains the newest txn log file with starting zxid < oldest retained snapshot's highest zxid.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)