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https://issues.apache.org/jira/browse/CASSANDRA-18675?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17759749#comment-17759749
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David Capwell commented on CASSANDRA-18675:
-------------------------------------------
This is turning out more complex than originally planned, mostly due to the
semantics of exclusive sync points... here is one problem found
T0: range movement so node1 now has a new range (that already existed)
T1: drop range (drop keyspace/ table)
T2: node1's bootstrap of the new range is failing as we have to run in the
latest epoch, which doesn't know the range!
Spoke with Benedict and we agreed to punt this work for now in favor of other
work, and to get back to this in ~3 weeks... but the starting work for add
keyspace support (mostly bug fixes) could go in now; so will create a new JIRA
for this.
> (Accord): C* stores keyspace in Range which will cause ranges to be removed
> from Accord when DROP KEYSPACE is performed
> -----------------------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-18675
> URL: https://issues.apache.org/jira/browse/CASSANDRA-18675
> Project: Cassandra
> Issue Type: Bug
> Components: Accord
> Reporter: David Capwell
> Assignee: David Capwell
> Priority: Normal
> Fix For: 5.x
>
>
> When translating the C* model to Accord we store the keyspace in the Range,
> this has the side effect that DROP KEYSPACE will cause Accord to see ranges
> removed between epoch versions. When this is enabled in BurnTest we see that
> there are cases where we stop making progress and can loop forever (until we
> OOM).
> Example
> {code}
> Failed on seed -1330125844737109546
> accord.burn.SimulationException: Failed on seed -1330125844737109546
> java.lang.OutOfMemoryError: GC overhead limit exceeded
> at java.util.HashMap.newNode(HashMap.java:1774)
> at java.util.HashMap.putVal(HashMap.java:632)
> at java.util.HashMap.put(HashMap.java:613)
> at
> accord.impl.InMemoryCommandStore$InMemorySafeStore.addCommandInternal(InMemoryCommandStore.java:582)
> at
> accord.impl.InMemoryCommandStore$InMemorySafeStore.addCommandInternal(InMemoryCommandStore.java:557)
> at
> accord.impl.AbstractSafeCommandStore$$Lambda$516/1241529534.accept(Unknown
> Source)
> at
> accord.impl.AbstractSafeCommandStore.getIfLoaded(AbstractSafeCommandStore.java:84)
> at
> accord.impl.AbstractSafeCommandStore.getInternalIfLoadedAndInitialised(AbstractSafeCommandStore.java:91)
> at
> accord.local.SafeCommandStore.ifLoadedAndInitialised(SafeCommandStore.java:194)
> at accord.local.Commands.lambda$updateWaitingOn$3(Commands.java:687)
> at accord.local.Commands$$Lambda$514/809300666.accept(Unknown Source)
> at accord.utils.SimpleBitSet.reverseForEach(SimpleBitSet.java:358)
> at
> accord.local.Command$WaitingOn$Update.forEachWaitingOnCommit(Command.java:1280)
> at accord.local.Commands.updateWaitingOn(Commands.java:685)
> at accord.local.Commands.initialiseWaitingOn(Commands.java:675)
> at accord.local.Commands.apply(Commands.java:481)
> at accord.messages.Apply.apply(Apply.java:121)
> at accord.messages.Apply.apply(Apply.java:34)
> {code}
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