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https://issues.apache.org/jira/browse/CASSANDRA-8054?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14167776#comment-14167776
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Aleksey Yeschenko commented on CASSANDRA-8054:
----------------------------------------------
Reopening because CASSANDRA-7923 exposed another issue. Since the cached
Metadata object has the mutable flags EnumSet (and copy() doesn't clone it), a
request with skipMetadata=true will add the flag for any future requests, even
without it.
And for re-prepared statements post CASSANDRA-7923 this means that for the
second prepare after any request with skipMetadata=true, the serializer will
skip serializing the columns when returning the PREPARED response to the client.
One option would be to simply revert CASSANDRA-7923, but since it actually
affects more than just that, the proper fix, IMO is to copy the flags in
Metadata#copy(). Attaching a simple patch that does that.
> EXECUTE request with skipMetadata=false gets no metadata in response
> --------------------------------------------------------------------
>
> Key: CASSANDRA-8054
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8054
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Olivier Michallat
> Assignee: Sylvain Lebresne
> Fix For: 2.1.1
>
> Attachments: 8054-2.1.txt, 8054-v2.txt
>
>
> This has been reported independently with the
> [Java|https://datastax-oss.atlassian.net/browse/JAVA-482] and
> [C++|https://datastax-oss.atlassian.net/browse/CPP-174] drivers.
> This happens under heavy load, where multiple client threads prepare and
> execute statements in parallel. One of them sends an EXECUTE request with
> skipMetadata=false, but the returned ROWS response has no metadata in it.
> A patch of {{Message.Dispatcher.channelRead0}} confirmed that the flag was
> incorrectly set on the response:
> {code}
> logger.debug("Received: {}, v={}", request,
> connection.getVersion());
> boolean skipMetadataOnRequest = false;
> if (request instanceof ExecuteMessage) {
> ExecuteMessage execute = (ExecuteMessage)request;
> skipMetadataOnRequest = execute.options.skipMetadata();
> }
> response = request.execute(qstate);
> if (request instanceof ExecuteMessage) {
> Rows rows = (Rows)response;
> boolean skipMetadataOnResponse =
> rows.result.metadata.flags.contains(Flag.NO_METADATA);
> if (skipMetadataOnResponse != skipMetadataOnRequest) {
> logger.warn("Inconsistent skipMetadata on streamId
> {}, was {} in request but {} in response",
> request.getStreamId(),
> skipMetadataOnRequest,
> skipMetadataOnResponse);
> }
> }
> {code}
> We observed the warning with (false, true) during our tests.
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