TDSParser stuck on TDS_COLMETADATA

[mmimica]

Driver version

9.4.0.jre11

SQL Server version

Microsoft SQL Server 2019 (RTM-CU11) (KB5003249) - 15.0.4138.2 (X64)

Client Operating System

Linux

JAVA/JVM version

16

Table schema

Problem description

SQLServerStatement.close() is stuck in an infinite loop.

   ...
   com.microsoft.sqlserver.jdbc.TDSTokenHandler.onColMetaData line: 256 
   com.microsoft.sqlserver.jdbc.TDSParser.parse line: 109 
   com.microsoft.sqlserver.jdbc.TDSParser.parse line: 37 
   com.microsoft.sqlserver.jdbc.TDSParser.parse line: 26 
   com.microsoft.sqlserver.jdbc.SQLServerStatement.processExecuteResults line: 1317 
   com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement$PrepStmtBatchExecCmd.processResponse line: 2700 
   com.microsoft.sqlserver.jdbc.TDSCommand.close line: 7487 
   com.microsoft.sqlserver.jdbc.SQLServerStatement.discardLastExecutionResults line: 147 
   com.microsoft.sqlserver.jdbc.SQLServerStatement.closeInternal line: 676 
   com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement.closeInternal line: 337 
   com.microsoft.sqlserver.jdbc.SQLServerStatement.close line: 691 
   ...

This is a code snipped from TDSCommand::close()

        while (!processedResponse) {
            try {
                processResponse(tdsReader);
            } catch (SQLServerException e) {
                if (logger.isLoggable(Level.FINEST))
                    logger.finest(this + ": close ignoring error processing response: " + e.getMessage());

                if (tdsReader.getConnection().isSessionUnAvailable()) {
                    processedResponse = true;
                    attentionPending = false;
                }
            }
        }

It loops while processedResponse is false. The TDSParser::parse() sets processedResponse=true only on end-of-stream. It never reaches end-of-stream because it bails out on tdsTokenHandler.onColMetaData(tdsReader); without reading the token (it only peeks).

JDBC trace logs

Sep 28, 2021 8:04:15 AM com.microsoft.sqlserver.jdbc.TDSTokenHandler onColMetaData
SEVERE: ConnectionID:7225 ClientConnectionId: 5bfa6ef7-b0af-4c8d-b832-0e04a50e286a: batch completion: Encountered TDS_COLMETADATA (0x81). SHOWPLAN is ON, ignoring.

[mmimica]

introduced in #666

[lilgreenbird]

hi @mmimica

Thank you for reporting this. As you mentioned this bug was inadvertently introduced in PR #666 to address issue #661. We have this in our backlog as this requires more investigation to come up with a fix that does not break the issue it was trying to fix. So this issue is in the backlog to be triaged along with other bugs and features when we plan for the next semester.

I saw that you created PR #1662 but unfortunately before we could review and merge it you would need to add junit tests and we would also need to verify that it does not break the old issue.