Re: Optimizer & boolean syntax - Mailing list pgsql-hackers

From Christopher Kings-Lynne
Subject Re: Optimizer & boolean syntax
Date
Msg-id 006b01c291b2$17f73b80$6600a8c0@internal
Whole thread Raw
In response to Re: Optimizer & boolean syntax  ("scott.marlowe" <scott.marlowe@ihs.com>)
Responses Re: Optimizer & boolean syntax
List pgsql-hackers
> > > "col" isn't of the general form "indexkey op constant" or "constant op
> > > indexkey" which I presume it's looking for given the comments in
> > > indxpath.c.  I'm not sure what the best way to make it work would be
given
> > > that presumably we'd want to make col IS TRUE/FALSE use an index at
the
> > > same time (since that appears to not do so as well).
> >
> > Not that I see the point of indexing booleans, but hey :)
>
> also, in reference to my last message, even if the % was 50/50, if the
> table was such that the bool was in a table next to a text field with 20k
> or text in it, an index on the bool would be much faster to go through
> than to seq scan the table.

Hmmm...I'm not sure about that.  Postgres's storage strategry with text will
be to keep it in a side table (or you can use ALTER TABLE/SET STORAGE) and
it will only be retrieved if it's in the select parameters.

Chris



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