[jira] [Commented] (BOOKKEEPER-326) DeadLock during ledger recovery

["Ivan Kelly (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/BOOKKEEPER-326?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13429196#comment-13429196 ] 

Ivan Kelly commented on BOOKKEEPER-326:
---------------------------------------

{quote}
-1 on the changes Ivan made to LedgerHandle. it breaks the throttle mechanism we deployed in BookKeeper now. for now, we use semaphore to do rate limit on both read/write operations, if permits are exhausted, the client which called addEntry/readEntries would be blocked until the permits are releases. the changes would not block client when permits are exhausted.{quote}
I had forgotten that PendingReadOp reaches into the ledger handle to take the permit. I think, even if don't move to a rate limiting semaphore, we should move all calls to the semaphore into LedgerHandle and remove all accesses from without. This way, we could make the change I suggested, which would be another safeguard against deadlocking, and is generally better software engineering practice also.

@Rakesh
The patch you have up is good. Is there a reason this JIRA isn't patch available?
                
> DeadLock during ledger recovery 
> --------------------------------
>
>                 Key: BOOKKEEPER-326
>                 URL: https://issues.apache.org/jira/browse/BOOKKEEPER-326
>             Project: Bookkeeper
>          Issue Type: Bug
>    Affects Versions: 4.1.0
>            Reporter: Vinay
>            Priority: Blocker
>         Attachments: BK_DeadLock.log, BOOKKEEPER-326.1.patch, BOOKKEEPER-326.2.patch, BOOKKEEPER-326.part2.diff, BOOKKEEPER-326.patch
>
>
> Deadlock found during ledger recovery. please find the attached thread dump.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira