work.
-Original Message-
From: Sergey Petrunya [mailto:pser...@askmonty.org]
Sent: Monday, December 14, 2009 5:58 PM
To: Manish Ranjan
Cc: mysql@lists.mysql.com
Subject: Re: different type column and keys for EXPLAIN
Manish,
On Mon, Dec 14, 2009 at 05:33:43PM +0530, Manish Ranjan wrote
I am using mysql 5.0.77 on RHEL 5. Storage engine in MyISAM.
Please refer to the below two statements. First query is checking for
lastname 'clarke' where as second query is checking for lastname 'clark'.
Rest everything is same with these two queries. However, the explain output
shows ref
I don't think there's an actual problem as such, the optimiser is just
making a decision to merge the lastname and firstname indices for the second
query. At a guess, I'd say that the cardinality of clark in your lastname
index is too high, so it uses both; the cardinality for clarke will be
Ranjan
Cc: mysql@lists.mysql.com
Subject: Re: different type column and keys for EXPLAIN
I don't think there's an actual problem as such, the optimiser is just
making a decision to merge the lastname and firstname indices for the second
query. At a guess, I'd say that the cardinality of clark
@lists.mysql.com
Subject: Re: different type column and keys for EXPLAIN
Heh. Try running analyze table, so the index stats are correct. If that
doesn't help, you may have stumbled upon an optimizer glitch, or maybe
there's something happening that I'm not seeing. If all else fails, try to
add index
, 2009 8:33 PM
To: Manish Ranjan
Cc: mysql@lists.mysql.com
Subject: Re: different type column and keys for EXPLAIN
I don't think there's an actual problem as such, the optimiser is just
making a decision to merge the lastname and firstname indices for the
second
query. At a guess, I'd say
Manish,
On Mon, Dec 14, 2009 at 05:33:43PM +0530, Manish Ranjan wrote:
I am using mysql 5.0.77 on RHEL 5. Storage engine in MyISAM.
Please refer to the below two statements. First query is checking for
lastname 'clarke' where as second query is checking for lastname 'clark'.
Rest
