I'm interested in any performance reports for long running sort runs in
8.1, as background information to improving sort performance for 8.2.
You'll need to enable the trace_sort parameter.
If you could provide all of the following, that would be most helpful
1. the log output relating to the trace_sort
2. details of the SQL query invoking the sort
3. details of the table(s) involved
so I can determine
i) the columns and datatypes of the sort keys.
ii) the total data volume being sorted
4. Any analysis you have of the data distributions, i.e. first column
has 1 million unique values, 2nd sort column has 11 values etc..
5. your work_mem and maintenance work_mem settings
6. server hardware details
First few posts can be on-list, after that privately please - until I
shout stop! Please only send me your worst sort case, not every case...
Any help much appreciated.
Best Regards, Simon Riggs