Re: performance of count(*)
От | Scott Ribe |
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Тема | Re: performance of count(*) |
Дата | |
Msg-id | 15F17483-3C8D-4D47-896A-96BFFA24B73C@elevated-dev.com обсуждение исходный текст |
Ответ на | Re: performance of count(*) (Andrew Sullivan <ajs@crankycanuck.ca>) |
Список | pgsql-general |
On May 6, 2011, at 4:15 PM, Andrew Sullivan wrote: > Yeah, in that case the HOT suggestions are very important. I strongly > recomment you experiment in a test system with real data and > pathological cases in particular, in order to see what happens when > the outlier cases inevitably, Murphy willing, crop up. That's not to > say you should arrange your plans for them, but forewarned is > forearmed. Again thanks. The HOT tip led me down the road of paying attention to my indexes, which led me to a nice realization abouthow to shrink the overall footprint of the materialized aggregates ;-) Which led me to a technique to seriously minimizeupdates... I didn't have to worry about bloat too much--overall activity level is not huge; the possibility of collisions on updatesis mostly because users tend to work on the same very small (but ever-shifting) subset of the data at the same time,but now I think I'm really set! -- Scott Ribe scott_ribe@elevated-dev.com http://www.elevated-dev.com/ (303) 722-0567 voice
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