[CASSANDRA-8054] EXECUTE request with skipMetadata=false gets no metadata in response

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 2.1.1
• Component/s: Legacy/CQL
• Severity: Normal
• Assignee: Sylvain Lebresne
• Reporter: Olivier Michallat

Authors

Sylvain Lebresne

Reviewers

Tom Hobbs

• Created: 03/Oct/14 20:03
• Updated: 16/Apr/19 09:31
• Resolved: 17/Oct/14 10:38

Description

This has been reported independently with the Java and C++ 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:

                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);
                    }
                }

We observed the warning with (false, true) during our tests.