You need to look at the GROUP BY clause
If all the columns from a GROUP BY clause
are not indexed or if the columns in the
GROUP BY clause are from different tables,
MySQL will use the temp table.
Please send your query to the MySQL List
and the structure of all tables in the query
----- Original Message -----
From: Francis <[EMAIL PROTECTED]>
To: MySQL General <mysql@lists.mysql.com>
Sent: Monday, November 6, 2006 8:50:40 AM GMT-0500 US/Eastern
Subject: " Copy to tmp table " optimize
Hi list,
An others question, I am working on projet and i made some test.
I use large databases, some table go up to 1.8g. The problem we have is
wend I try to select data in table whit a group by function and I got "
Copy to tmp table " This function take a long time to execute. I check
on my server for the cpu usage and no hang up, no hang up on hardrive,
the only hang up I have is on memory.
1 Question, the " copy to tmp table " function can optimize to
get faster ?
2 Question, what is the max table I can create in databses ?
because, the way I found to optimize " copy to tmp table " is by
spliting the data in my table in multiple tables to lower the size...But
if I do this way, the table counts on my database can go up to 600
tables :S I don't think is a good way to do this.
Ty for your help and sorry for my english...
Francis !
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