| From: | Yeb Havinga <yebhavinga(at)gmail(dot)com> |
|---|---|
| To: | Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov> |
| Cc: | Greg Smith <greg(at)2ndquadrant(dot)com>, Matthew Wakeling <matthew(at)flymine(dot)org>, Eliot Gable <egable+pgsql-performance(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: B-Heaps |
| Date: | 2010-06-18 20:18:41 |
| Message-ID: | 4C1BD4A1.4070406@gmail.com |
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| Thread: | |
| Lists: | pgsql-performance |
Kevin Grittner wrote:
> Yeb Havinga <yebhavinga(at)gmail(dot)com> wrote:
>
>
>> concerning gist indexes:
>>
>> 1) with larger block sizes and hence, larger # entries per gist
>> page, results in more generic keys of those pages. This in turn
>> results in a greater number of hits, when the index is queried, so
>> a larger part of the index is scanned. NB this has nothing to do
>> with caching / cache sizes; it holds for every IO model. Tests
>> performed by me showed performance improvements of over 200%.
>> Since then implementing a speedup has been on my 'want to do
>> list'.
>>
>
> As I recall, the better performance in your tests was with *smaller*
> GiST pages, right? (The above didn't seem entirely clear on that.)
>
Yes, making pages smaller made index scanning faster.
-- Yeb
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