On Jan 31, 2008 12:08 AM, Gregory Stark <[EMAIL PROTECTED]> wrote: > "Decibel!" <[EMAIL PROTECTED]> writes: > > > I think that before doing any of that you'd be much better off > > investigating how much performance penalty there is for maxing out > > default_statistict_target. If, as I suspect, it's essentially 0 on > > modern hardware, then I don't think it's worth any more effort. > > That's not my experience. Even just raising it to 100 multiplies the number of > rows ANALYZE has to read by 10. And the arrays for every column become ten > times larger. Eventually they start being toasted...
+1. From the tests I did on our new server, I set the default_statistict_target to 30. Those tests were mainly based on the ANALYZE time though, not the planner overhead introduced by larger statistics - with higher values, I considered the ANALYZE time too high for the benefits. I set it higher on a per column basis only if I see it can lead to better stats but from all the tests I did so far, it was sufficient for our data set. -- Guillaume ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
