
> Can  someone explain why the following query takes  1 second when using 
> LIKE and takes 30 seconds when replacing LIKE by = in the WHERE ? 

Because there is no optimization built in, that notices, that your
string does not contain a wildcard and would translate the restriction 
correspondingly. It is currently executed more or less like below:
	(I3.nameInfluence >= 'inf_vitesse' and I3.nameInfluence < 'inf_vitessf'
 	 and I3.nameInfluence LIKE  'inf_vitesse')
I already wanted to try to add this optimization myself, but lacked the time so far.
Anybody want to volunteer ?

TODO: add LIKE optimization to use = if constant does not contain any wildcards

Andreas

Thu, 5 Jul 2001 09:55:04 +0200 
Zeugswetter Andreas SB <ZeugswetterA@wien.spardat.at>
AW: Strange query execution time
Zeugswetter Andreas SB <ZeugswetterA@wien.spardat.at> writes:
> TODO: add LIKE optimization to use = if constant does not contain any wildcards

Your information is obsolete ... try looking at the EXPLAIN VERBOSE
output for such a query.

			regards, tom lane

Thu, 05 Jul 2001 09:57:35 -0400
Tom Lane <tgl@sss.pgh.pa.us>
Re: AW: Strange query execution time 