> 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

Responses

• Re: AW: Strange query execution time at 2001-07-05 13:57:35 from Tom Lane

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