Re: performance question
От | Manfred Koizar |
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Тема | Re: performance question |
Дата | |
Msg-id | 1k3o2v01b5ceh937kibrojn2fjks3fc93t@4ax.com обсуждение исходный текст |
Ответ на | performance question ("Moritz Lennert" <mlennert@club.worldonline.be>) |
Список | pgsql-sql |
On Mon, 20 Jan 2003 12:40:34 +0100 (CET), "Moritz Lennert" <mlennert@club.worldonline.be> wrote: >I have a table with some 2.2 million rows on a Pentium4, 1.8GHz with 512 >MB RAM. >Some queries I launch take quite a long time, and I'm wondering whether >this is normal,or whether I can get better performance somehow. Moritz, we need more information. Please show us. your PG version. CREATE TABLE .... indices. your query. EXPLAIN ANALYZEoutput. your settings, especially shared_buffers, sort_mem, random_page_cost, effective_cache_size >One question I asked myself is whether the use of char(2) is the best >option. The column (and most others in the table) contains codes that >designate different characteristics (for ex. in a column 'sex' one would >find '1'=male, '2'=female). char(2) needs 8 bytes, smallint only 2 bytes (unless followed by a column with 4 or 8 byte alignment). Instead of char(1) (8 bytes) you might want to use the Postgres specific type "char" (with the double quotes!) needing only 1 byte. ServusManfred
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