… 5 Follow was index。 the explain: type:index，Extra:Using index; Using temporary; Using filesort i am chinese, so my english is bad…..sorry….. THANKS…
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
… | Using index; Using temporary; Using filesort | | 1 | SIMPLE | lineitem | ref | i_l_suppkey | i_l_suppkey | 5 | dbt3.supplier.s_suppkey | 250 | 100.00 | Using where… | Using where; Using index; Using temporary; Using filesort | | 1 | SIMPLE | lineitem | ref | i_l_suppkey | i_l_suppkey | 5 | dbt3.supplier.s_suppkey | 292 | 100.00 | Using…
Post: Enum Fields VS Varchar VS Int + Joined table: What is Faster?
January 24, 2008 By 30 Comments
… key: NULL key_len: NULL ref: NULL rows: 1439943 Extra: Using temporary; Using filesort *************************** 2. row *************************** id: 1 select_type: SIMPLE table: s type… and extra sort pass (filesort) is required, which also makes MySQL to store Join result in temporary table to do the sort…
Comment: What does Using filesort mean in MySQL?
March 5, 2009 By 27 Comments
… Extra 1 SIMPLE sol ALL (NULL) (NULL) (NULL) (NULL) 3 Using temporary; Using filesort 1 SIMPLE dom ALL (NULL) (NULL) (NULL) (NULL) 36 1… 1 1 SIMPLE cts ALL (NULL) (NULL) (NULL) (NULL) 99 Using where 1 SIMPLE cb eq_ref PRIMARY,cou_id PRIMARY…
Post: GROUP_CONCAT useful GROUP BY extension
September 4, 2006 By 49 Comments
…to MySQL server side. Also it can be handy to use result concatenated string as part of IN statement: Sure, …with one query with joins, but sometimes we need the temporary ids in clients code, for example to execute query …NULL statement after GROUP_BY to avoid unnecessary sorting with filesort // //
Comment: What does Handler_read_rnd mean?
June 16, 2010 By 15 Comments
… | | Handler_read_next | 59 | Whereas adding ORDER BY RAND() adds “using temporary; using filesort” to the EXPLAIN, and gives the following: | Handler_read_first…
Post: What does Using filesort mean in MySQL?
March 5, 2009 By 27 Comments
… to work at Percona, and I asked you “what does Using filesort mean in EXPLAIN,” what would you say? I have asked… not the same thing. First of all, this is Using temporary. Secondly, temporary tables may go to disk if they are too big… I might ask you the other reason temporary tables go to disk!) The truth is, filesort is badly named. Anytime a sort…
Post: Using GROUP BY WITH ROLLUP for Reporting Performance Optimization
September 17, 2007 By 14 Comments
… with it. The thing is – it is using filesort as group by execution method, not temporary table as ordinary GROUP BY: mysql> explain…: NULL key_len: NULL ref: NULL rows: 37748736 Extra: Using where; Using temporary; Using filesort 1 row in set (0.01 sec) mysql> explain select… Extra: Using where; Using filesort 1 row in set (0.00 sec) As I forced FileSort execution method for GROUP BY by using SQL_BIG…
Post: The new cool MySQL patch has landed! Check your queries performance!
October 31, 2007 By 16 Comments
…_join means any of the joins didn’t use indexes. If a temporary table is required for query execution Tmp_table will… will state that. Filesort is for indicating that filesort algorithm was used, while Disk_filesort means that sorting was done through temporary files. INNODB USAGE…
Post: ORDER BY ... LIMIT Performance Optimization
September 1, 2006 By 100 Comments
… | k | 4 | const | 1 | Using temporary; Using filesort | | 1 | SIMPLE | t | ref | k | k | 4 | test.test.i | 1 | Using where; Using index | +—-+————-+——-+——+—————+——+———+————-+——+———————————+ 2 rows in… | k | 4 | const | 1 | Using temporary; Using filesort | | 1 | SIMPLE | t | ref | k | k | 4 | test.test.i | 1 | Using where; Using index | +—-+————-+——-+——+—————+——+———+————-+——+———————————+ 2 rows in…
