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https://issues.apache.org/jira/browse/IGNITE-6252?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16444548#comment-16444548
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Igor Rudyak commented on IGNITE-6252:
-------------------------------------
[~kotamrajuyashasvi] right after
[handlePreparedStatementClusterError|https://github.com/apache/ignite/blob/master/modules/cassandra/store/src/main/java/org/apache/ignite/cache/store/cassandra/session/CassandraSessionImpl.java#L252]
method call, there is a call to
[refresh|https://github.com/apache/ignite/blob/master/modules/cassandra/store/src/main/java/org/apache/ignite/cache/store/cassandra/session/CassandraSessionImpl.java#L253]
prepared statement using new Cassandra session. Thus subsequent statements
running by the *same thread* should be good.
However there could be other threads trying to refresh session because they are
also failed to execute prepared statement. Here we have two cases:
1) All threads trying to refresh Cassandra session at the same time. This case
should be handled properly by this
[logic|https://github.com/apache/ignite/blob/master/modules/cassandra/store/src/main/java/org/apache/ignite/cache/store/cassandra/session/CassandraSessionImpl.java#L879],
preventing threads to refresh session multiple times. Also because of this you
may see [such
warnings|https://github.com/apache/ignite/blob/master/modules/cassandra/store/src/main/java/org/apache/ignite/cache/store/cassandra/session/CassandraSessionImpl.java#L880],
which is fine.
2) It's possible that some threads will try to refresh Cassandra session
sequentially, because scheduling among threads is unpredictable and while
refreshing session other threads which are trying to
[execute|https://github.com/apache/ignite/blob/master/modules/cassandra/store/src/main/java/org/apache/ignite/cache/store/cassandra/session/CassandraSessionImpl.java#L231]
prepared statement will be locked, cause
[session()|https://github.com/apache/ignite/blob/master/modules/cassandra/store/src/main/java/org/apache/ignite/cache/store/cassandra/session/CassandraSessionImpl.java#L538]
call is synchronized. Thus we are running into number of extra (and
unnecessary) refreshments of Cassandra session which is a problem.
[~kotamrajuyashasvi] Could you please create a separate ticket for this issue
(case 2)? Current ticket is about another problem which is fixed now.
> Cassandra Cache Store Session does not retry if prepare statement failed
> ------------------------------------------------------------------------
>
> Key: IGNITE-6252
> URL: https://issues.apache.org/jira/browse/IGNITE-6252
> Project: Ignite
> Issue Type: Bug
> Components: cassandra
> Affects Versions: 2.0, 2.1
> Reporter: Sunny Chan
> Assignee: Igor Rudyak
> Priority: Major
> Fix For: 2.6
>
>
> During our testing, we have found that certain warning about prepared
> statement:
> 2017-08-31 11:27:19.479
> org.apache.ignite.cache.store.cassandra.CassandraCacheStore
> flusher-0-#265%xxxx% WARN CassandraCacheStore - Prepared statement cluster
> error detected, refreshing Cassandra session
> com.datastax.driver.core.exceptions.InvalidQueryException: Tried to execute
> unknown prepared query : 0xc7647611fd755386ef63478ee7de577b. You may have
> used a PreparedStatement that was created with another Cluster instance.
> We notice that after this warning occurs some of the data didn't persist
> properly in cassandra cache. After further examining the Ignite's
> CassandraSessionImpl code in method
> execute(BatchExecutionAssistance,Iterable), we found that at around [line
> 283|https://github.com/apache/ignite/blob/86bd544a557663bce497134f7826be6b24d53330/modules/cassandra/store/src/main/java/org/apache/ignite/cache/store/cassandra/session/CassandraSessionImpl.java#L283],
> if the prepare statement fails in the asnyc call, it will not retry the
> operation as the error is stored in [line
> 269|https://github.com/apache/ignite/blob/86bd544a557663bce497134f7826be6b24d53330/modules/cassandra/store/src/main/java/org/apache/ignite/cache/store/cassandra/session/CassandraSessionImpl.java#L269]
> and cleared in [line
> 277|https://github.com/apache/ignite/blob/86bd544a557663bce497134f7826be6b24d53330/modules/cassandra/store/src/main/java/org/apache/ignite/cache/store/cassandra/session/CassandraSessionImpl.java#L277]
> but it was not checked again after going through the [ResultSetFuture
> |https://github.com/apache/ignite/blob/86bd544a557663bce497134f7826be6b24d53330/modules/cassandra/store/src/main/java/org/apache/ignite/cache/store/cassandra/session/CassandraSessionImpl.java#L307].
> I believe in line 307 you should check for error != null such that any
> failure will be retry.
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