Re: Configuration Advice
От | Steve |
---|---|
Тема | Re: Configuration Advice |
Дата | |
Msg-id | Pine.GSO.4.64.0701171942190.4471@kingcheetah.tanabi.org обсуждение исходный текст |
Ответ на | Re: Configuration Advice (Chris Browne <cbbrowne@acm.org>) |
Список | pgsql-performance |
> The thought: > > - Load the big chunk of data into a new table > > - Generate some minimal set of indices on the new table > > - Generate four queries that compare old to new: > q1 - See which tuples are unchanged from yesterday to today > q2 - See which tuples have been deleted from yesterday to today > q3 - See which tuples have been added > q4 - See which tuples have been modified > > If the "unchanged" set is extremely large, then you might see benefit > to doing updates based on deleting the rows indicated by q2, > inserting rows based on q3, and updating based on q4. > > In principle, computing and applying those 4 queries might be quicker > than rebuilding from scratch. > > In principle, applying q2, then q4, then vacuuming, then q3, ought to > be "optimal." This looks like an interesting idea, and I'm going to take a look at how feasible it'll be to impletement. I may be able to combine this with Mr. Wagner's idea to make a much more efficient system overall. It's going to be a pretty big programming task, but I've a feeling this summarizer thing may just need to be re-written with a smarter system like this to get something faster. Thanks! Steve
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