Shridhar Daithankar writes: First - many thanks for your suggestions and pointers to further info.
I have been trying some of them with some interesting results! > Harry Broomhall wrote: > > #effective_cache_size = 1000 # typically 8KB each > > #random_page_cost = 4 # units are one sequential page fetch cost > > You must tune the first one at least. Try > http://www.varlena.com/varlena/GeneralBits/Tidbits/perf.html to tune these > parameters. Changing effective_cache_size seemed to have very little effect. I took it in steps up to 300MB (the machine has 640MB memory), and the differences in speed were less than 10%. [SNIP] > > What happens if you turn off hash joins? This makes the non vacuum version about 40% slower, and the vacuum version to the same speed (i.e. about 4X faster than it had been!). > Also bump sort memory to something > good.. around 16MB and see what difference does it make to performance.. This was interesting. Taking it to 10MB made a slight improvement. Up to 20MB and the vacuum case improved by 5X speed, but the non-vacuum version slowed down. Putting it up to 40MB slowed both down again. I will need to test with some of the other scripts and functions I have written, but it looks as if selective use of more sort memory will be useful. Regards, Harry. ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
