Comments on: Performance notes on INFORMATION_SCHEMA tables

By: Cyril Scetbon

Cyril Scetbon — Mon, 01 Dec 2008 20:21:01 +0000

Keep in mind that the Perl motto is usable with MySQL Databases.

By: Gregory Haase

Gregory Haase — Mon, 01 Dec 2008 19:25:49 +0000

I guess that is learning number 3.) Don't over-complicate things. As Giuseppe has pointed out, a simple join will suffice:

SELECT DISTINCT a.table_name
  FROM information_schema.partitions a,
       information_schema.columns b
 WHERE a.table_name = b.table_name
   AND a.table_name like '%reporting'
   AND a.partition_name is not null
   AND b.column_name = 'datestring';
.....
13 rows in set (21.80 sec)

By: Giuseppe Maxia

Giuseppe Maxia — Mon, 01 Dec 2008 19:05:00 +0000

Greg,
did you try with a JOIN, instead of a subquery?

SELECT DISTINCT a.table_name
FROM
information_schema.partitions a
INNER JOIN information_schema.COLUMNS b
ON a.table_name = b.table_name
AND a.table_schema = b.table_schema
WHERE
a.partition_name IS NOT NULL
AND a.table_name LIKE ‘%reporting’
AND column_name = ‘datestring’ ;

This should be faster.