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https://issues.apache.org/jira/browse/ZOOKEEPER-3231?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jiafu Jiang updated ZOOKEEPER-3231:
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Description:
I read the ZooKeeper source code, and I find the purge task use
FileTxnSnapLog#findNRecentSnapshots to find snapshots, but the method does not
check whether the snapshots are valid.
Consider a worse case, a ZooKeeper server may have many invalid snapshots, and
when a purge task begins, it will use the zxid in the last snapshot's name to
purge old snapshots and transaction logs, then we may lost data.
I think we should use FileSnap#findNValidSnapshots(int) instead of
FileSnap#findNRecentSnapshots in FileTxnSnapLog#findNRecentSnapshots, but I am
not sure.
was:
I read the ZooKeeper source code, and I find the purge task use
FileTxnSnapLog#findNRecentSnapshots to find snapshots, but the method does not
check whether the snapshots are valid.
Consider a worse case, a ZooKeeper server may have many invalid snapshots, and
when a purge task begins, it will use the zxid in the last snapshot's name to
purge old snapshots and transaction logs, then we may lost data.
I think we should use FileSnap#findNValidSnapshots(int) instead of
FileSnap#findNRecentSnapshots in FileTxnSnapLog#findNRecentSnapshots. I am not
sure.
> Purge task may lost data when we have many invalid snapshots.
> --------------------------------------------------------------
>
> Key: ZOOKEEPER-3231
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-3231
> Project: ZooKeeper
> Issue Type: Bug
> Components: server
> Affects Versions: 3.5.4, 3.4.13
> Reporter: Jiafu Jiang
> Priority: Major
>
> I read the ZooKeeper source code, and I find the purge task use
> FileTxnSnapLog#findNRecentSnapshots to find snapshots, but the method does
> not check whether the snapshots are valid.
> Consider a worse case, a ZooKeeper server may have many invalid snapshots,
> and when a purge task begins, it will use the zxid in the last snapshot's
> name to purge old snapshots and transaction logs, then we may lost data.
> I think we should use FileSnap#findNValidSnapshots(int) instead of
> FileSnap#findNRecentSnapshots in FileTxnSnapLog#findNRecentSnapshots, but I
> am not sure.
>
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