From: | Michal Politowski <mpol+pg(at)meep(dot)pl> |
---|---|
To: | pgsql-general(at)postgresql(dot)org |
Subject: | Why would a scan take so long? |
Date: | 2010-10-01 15:13:58 |
Message-ID: | 20101001151358.GA12255@meep.pl |
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Lists: | pgsql-general |
EXPLAIN SELECT count(DISTINCT catalog.id) FROM catalog WHERE flag=false;
QUERY PLAN
-----------------------------------------------------------------------------------------
Aggregate (cost=1615927.27..1615927.28 rows=1 width=8)
-> Seq Scan on catalog (cost=0.00..1603214.56 rows=5085084 width=8)
Filter: (NOT flag)
SELECT pg_size_pretty(pg_relation_size('catalog'));
pg_size_pretty
----------------
9380 MB
Nothing else is going on the system, during the query disk reads rise from
around 0 to > 100MB/s, so I would assume it should take a couple minutes
and it takes ten times longer:
Time: 1495549.716 ms
What am I missing?
--
Michal Politowski
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