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Update performance on large table

Hi guys -

I have a table that is approaching 4 gigs. I have optimized as much as
I can with indexes so that select statements are ok, but updating
entries seems to be taking a bit of time. I have 2 questions:

1) I know about the EXPLAIN command for select queries, but is there
something like that for updates? I get an error when I try to do
"EXPLAIN UPDATE mytable..." Do updates use indexes the same way as
selects?

2) Would breaking the table up into seperate tables and then using a
merge table increase the performace? I've heard that key reads are
slower on merge tables - but since I could make 4 tables of a gig
each, wouldn't it be faster opening up 1 smaller file to make an
update instead of a huge one?

Any comments are greatly appreciated.

Thanks!
Shane
Jul 20 '05 #1
0 1795

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