From: | Ozz Nixon <ozznixon(at)gmail(dot)com> |
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To: | PostgreSQL <pgsql-general(at)postgresql(dot)org> |
Cc: | Ozz Nixon <ozznixon(at)gmail(dot)com> |
Subject: | Why Select Count(*) from table - took over 20 minutes? |
Date: | 2010-10-26 17:18:41 |
Message-ID: | D4718551-6E2A-4840-8BCF-20901EA0E570@gmail.com |
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Thread: | |
Lists: | pgsql-general |
I am the only user on this system right now, and one table select count(*) took over 20 minutes:
wikitags exists and has 58,988,656 records.
Structure (in pascal) is:
quer.SQL.Add('create table '+DBTags+' (');
quer.SQL.Add(' pagename '+SQL_TITLE+'(100) not null,');
quer.SQL.Add(' tagword '+SQL_TITLE+'(15) not null,');
quer.SQL.Add(' soundex2 '+SQL_TITLE+'(4) not null,');
quer.SQL.Add(' metaphone '+SQL_TITLE+'(15) not null,');
quer.SQL.Add(' metaphone2 '+SQL_TITLE+'(22) not null,');
quer.SQL.Add(' carverphone '+SQL_TITLE+'(22) not null,');
quer.SQL.Add(' instances '+SQL_INT32+' not null,');
if SQL_NAME_PRIMARY_KEYS then quer.SQL.Add(' constraint '+DBTags+'_PK');
quer.SQL.Add(' primary key(pagename, tagword, instances)');
quer.SQL.Add(')');
where SQL_TITLE = 'varchar', SQL_IN32 = 'int'
I have hung off indexes for each column, to resolve my previous "performance" issue from 3+ weeks ago. However, COUNT() is still dog slow - this table is a write once, read many... *never* update, nor delete.
Any suggestions?
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Next Message | Bill Moran | 2010-10-26 17:26:31 | Re: Why Select Count(*) from table - took over 20 minutes? |
Previous Message | Szymon Guz | 2010-10-26 14:37:58 | Re: what can depend on index |