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https://issues.apache.org/jira/browse/CASSANDRA-8054?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14169297#comment-14169297
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Sylvain Lebresne commented on CASSANDRA-8054:
---------------------------------------------

I agree that not copying the flags is an overside of the initial patch, though 
I'd really put the flag copying in the {{copy}} method. But aside that, +1.

bq. would prefer the initial Metadata have everything immutable/null in it, and 
only the Metadata returned from copy() to use mutable things

That's why my initial idea in went withCASSANDRA-7120 was to make Metadata 
basically immutable and copy to do changes, but it forces to do more copy than 
necessary and required a couple other chances. I don't mind terribly tbh.

> 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: 2.0.11, 2.1.1
>
>         Attachments: 8054-2.1.txt, 8054-fix.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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