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Posted to dev@bookkeeper.apache.org by "Flavio Junqueira (JIRA)" <ji...@apache.org> on 2012/06/06 00:26:23 UTC
[jira] [Commented] (BOOKKEEPER-287) NoSuchElementException in
LedgerCacheImpl
[ https://issues.apache.org/jira/browse/BOOKKEEPER-287?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13289794#comment-13289794 ]
Flavio Junqueira commented on BOOKKEEPER-287:
---------------------------------------------
Sounds like a blocker to me, is it right?
My findings so far. It seems to happen in the case that in LedgerCacheImpl.grabCleanPage we have that:
# pageCount >= pageLimit
# cleanLedger is empty
# pages is empty
It doesn't sound like a race on cleanLedgers because it is only manipulated in grabCleanPages and deleteLedger, both accesses synchronized. Consequently, it sounds like an issue with pages. If pages were not empty, then the for loop in the "if (cleanLedgers.isEmpty())" would have added elements to cleanLedgers. My conclusion is that pages is empty. We remove elements from pages in deleteLedger, so I'm wondering if all ledgers have been deleted between the first "synchronized(this)" block and outerLoop. If this is the case, the only solution I see is to make the whole method synchronized.
I don't know how to reproduce this.
> NoSuchElementException in LedgerCacheImpl
> -----------------------------------------
>
> Key: BOOKKEEPER-287
> URL: https://issues.apache.org/jira/browse/BOOKKEEPER-287
> Project: Bookkeeper
> Issue Type: Bug
> Reporter: Flavio Junqueira
> Priority: Blocker
> Fix For: 4.1.0, 4.2.0
>
>
> 2012-06-05 16:24:29,596 - WARN [NIOServerFactory-3181:NIOServerFactory@128] - Exception in server socket loop: /0.0.0.0
> java.util.NoSuchElementException
> at java.util.LinkedList.getFirst(LinkedList.java:109)
> at org.apache.bookkeeper.bookie.LedgerCacheImpl.grabCleanPage(LedgerCacheImpl.java:478)
> at org.apache.bookkeeper.bookie.LedgerCacheImpl.grabLedgerEntryPage(LedgerCacheImpl.java:169)
> at org.apache.bookkeeper.bookie.LedgerCacheImpl.putEntryOffset(LedgerCacheImpl.java:199)
> at org.apache.bookkeeper.bookie.InterleavedLedgerStorage.addEntry(InterleavedLedgerStorage.java:109)
> at org.apache.bookkeeper.bookie.LedgerDescriptorImpl.addEntry(LedgerDescriptorImpl.java:81)
> at org.apache.bookkeeper.bookie.Bookie.addEntryInternal(Bookie.java:656)
> at org.apache.bookkeeper.bookie.Bookie.addEntry(Bookie.java:691)
> at org.apache.bookkeeper.proto.BookieServer.processPacket(BookieServer.java:368)
> at org.apache.bookkeeper.proto.NIOServerFactory$Cnxn.readRequest(NIOServerFactory.java:310)
> at org.apache.bookkeeper.proto.NIOServerFactory$Cnxn.doIO(NIOServerFactory.java:208)
> at org.apache.bookkeeper.proto.NIOServerFactory.run(NIOServerFactory.java:123)
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