Am 30.06.2008 um 16:59 schrieb Steinar H. Gunderson:
On Mon, Jun 30, 2008 at 09:16:06AM +0200, Moritz Onken wrote:
the result table has 20.000.000 records and the item table 5.000.000.
The query
select count(1) from result where url in (select shorturl from item
where shorturl = result.url);
will take about 8 hours (still running, just guessing). Is this
reasonable on a system with 1 GB of RAM and a AMD Athlon 64 3200+
processor? (1 SATA HDD)
I really don't see what your query tries to accomplish. Why would
you want
"url IN (... where .. = url)"? Wouldn't you want a different qualifier
somehow?
well, it counts the number of rows with urls which already exist in
another
table.
How would you describe the query?
If the "(select shorturl from item where shorturl = result.url)"
clause is empty the row is not counted, that's what I want...
greetings,
moritz
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