Re: [HACKERS] Use "average field correlation per hard disk

2004-03-09 Thread Philip Warner
At 04:08 PM 10/03/2004, Tom Lane wrote: None at the moment, but I'm open to suggestions. It seems like we might need different stats for equality probes than range probes. What about my suggestion from August 2000: "There might be a way to side-step the issue here. I assume that the index

Re: [HACKERS] Use "average field correlation per hard disk page" instead of global one?

2004-03-09 Thread Tom Lane
Alexey Nalbat <[EMAIL PROTECTED]> writes: > Due to the updating algorithm the physical order of tuples in the > table happens to be such that all equal keys are placed together, > but not ordered globally. Hmm... this is of course a weak spot of the correlation-based estimation method. If you wer

[HACKERS] Use "average field correlation per hard disk page" instead of global one?

2004-03-09 Thread Alexey Nalbat
Hello. I have a table of 2'500'000 tuples and 100'000 pages, and an index on non-unique field, to each key value corresponds approximately 50'000 tuples. Due to the updating algorithm the physical order of tuples in the table happens to be such that all equal keys are placed together, but not ord