Re: [GENERAL] indexed regex select optimisation missing?
Peter Eisentraut <e99re41@docs.uu.se>
From: Peter Eisentraut <e99re41@DoCS.UU.SE>
To: Stuart Woolford <stuartw@newmail.net>
Cc: "Gene Selkov, Jr." <selkovjr@mcs.anl.gov>, pgsql-general@postgreSQL.org
Date: 1999-11-04T09:40:21Z
Lists: pgsql-general
On Thu, 4 Nov 1999, Stuart Woolford wrote: > unfortunately '^whatever.*' is what I'm trying to locate (ie: all words > starting with whatever, but with nay trailing text), the problem seems to be in > the termination of the index scan, not in the actual regex match (which actually > seems very good, speed wise..) otherwise I could just use ='whatever', which > runs very very fast. Isn't "all words that start with whatever but without trailing text" the same as = 'whatever'? From a regex point of view '^whatever' and '^whatever.*' are exactly equivalent, but I can see where one could fail to optimize properly. But that could even be a problem in the regex library, which is not any of the PostgreSQL developers' domain and which is used in other products as well. -Peter -- Peter Eisentraut Sernanders vaeg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden