Re: How to get around LIKE inefficiencies?]

> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Sorry to be getting in here late.  Have you tried CLUSTER?
> 
> Prolly won't help much.  I think what he's getting burnt by
> is that the planner thinks that an indexscan based on the
> LIKE 'http://www.postgresql.org/%' condition will be extremely
> selective --- it has no idea that most of the URLs in his table
> will match that prefix.  It's ye same olde nonuniform-distribution
> problem; until we have better statistics, there's not much hope
> for a non-kluge solution.

But I think it will help.  There will be lots of index lookups, but they
will be sequential in the heap, not random over the heap.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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