Hi Matt, thanks for answezring!
A disk-based temp table is used if you're SELECTing a column [that can
be] longer than 255 characters (BLOB/TEXT to MySQL). This is because the
in memory HEAP tables don't currently support variable length rows.
Using something like LEFT(text_col, 255), if
Hi All!
I think I am getting close to the solution.
In fact, mysql creates tmp tables beacause I GROUP BY a query that joins
tables. According to the manual, group bys on joins always creates a
temporary table.
Now the question is, why is this table a temporary disk table???
Thanks in advance.
Probably cause your table ends up being bigger than:
SHOW VARIABLES LIKE 'tmp_table%';
I don't think so. As I stated before (sorry I didn't include my first post),
I have :
tmp_table_size = 512M
max_heap_table_size=512M
From my calculation, I would have ~2000 rows in the result of my query,
Hi!
I have a query that allways creates temporary tables to disk (the ratio
created_tmp_disk_tables/created_tmp_tables is close to 0.8, but I think it
is 1 for this particular query).
This query joins 4 tables, groups by a field a orders by another field (or
sometimes an sql variable).
When I
: Arnaud
Sent: Wednesday, November 19, 2003 2:18 AM
Subject: using temporary / using filesort and disk tables
Hi!
I have a query that allways creates temporary tables to disk (the
ratio
created_tmp_disk_tables/created_tmp_tables is close to 0.8, but I
think it
is 1 for this particular query
