Flow Control and Spawned Work - comment by carrie

Hello C.Y.

There is no way that I know of to identify if an individual query was delayed waiting to get an AWT. You can, however, see whether requests within a workload were delayed waiting for an AWT, and a count of how many per logging interval. That is by looking at the ResUsageSPS table, which in 13.10 carries information about delays from waiting for AWTs within workloads. 14.0 has even clearer information, as it doesn't rely on SpareCount columns, as does 13.10.

The two fields in the SPS table you want to look at are WorkMsgReceiveDelayMax (SpareCount03 in 13.10) and QWaitTimeMax. Those two columns will tell you what the max wait times within that workload are (for all queries that classify to that workload), due to AMP worker task shortages. You can see the explanations for those columns in the ResUsage manual, the chapter on ResusageSPS.

There will be a new orange book on using Resusage table information for AMP worker task analysis that will be posted in early January, which goes into quite a bit more detail an analyzing delays caused by AWTs.

Thanks, -Carrie