Notes

If the SQL runtime warning output facility is used and number-of-secondssec or auto is omitted in both the PDCWAITTIMEWRNPNT and the pd_cwaittime_wrn_pnt operands, the SQL runtime warning output facility increases the number of system calls issued, even though no warning information is being produced, because the facility still must obtain SQL start times and execution times. To minimize the effects of this on performance, specify number-of-secondssec or auto.
Depending on the exact time at which SQL runtime warning information is output, both of the conditions for output of an SQL runtime warning information file explained in 8.9.1(5) Conditions under which warning information is output might be satisfied. This means that SQL runtime warning information might be output twice for the same SQL statement.
A small period of time elapses from when the client issues a processing request until the SQL runtime warning output facility begins measuring the SQL execution time, and from when the facility has finished measuring the SQL execution time until its execution results arrive at the client, due to output processing, communications processing, and other factors handled by the facility. If this processing time takes too long due to the network or I/O load, the following behaviors might occur:
- Even though the client wait time satisfied the conditions for output of an SQL runtime warning information file, no SQL runtime warning information file was output.
- Although the server process was terminated forcibly due to a PDCWAITTIME timeout, the SQL execution time that was output to the SQL runtime warning information file does not satisfy the conditions for warning information to be output.

8.9.5 Notes