On 07/12/2013 04:43 PM, Josh Berkus wrote:
As for the counts on the tables:
table1 3,653,472
table2 2,191,314
table3 25,676,589
I think it's safe to assume right now that any resulting joins are not
one-to-one
Hmmm? How is doing a subselect in the SELECT clause even working, then?
Oh my, this is sad. the query in all returns 9,955,729 rows, so the sub
queries are run on each of these resulting rows, however in this entire
result set, subquery 1 returns 16 distinct rows, subquery 2 returns 63
different rows, but those sub queries are run over 10 million times to
return these few distinct rows. So it's running many times, but
returning the same small set of data over and over again.
- Brian F
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