Re: Strange (?) Index behavior? - Mailing list pgsql-performance

From Matt Clark
Subject Re: Strange (?) Index behavior?
Date
Msg-id 007a01c4c349$092cdae0$8300a8c0@solent
Whole thread Raw
In response to Strange (?) Index behavior?  (Allen Landsidel <alandsidel@gmail.com>)
List pgsql-performance
> For some reason it's a requirement that partial wildcard
> searches are done on this field, such as "SELECT ... WHERE
> field LIKE 'A%'"
>
> I thought an interesting way to do this would be to simply
> create partial indexes for each letter on that field, and it
> works when the query matches the WHERE clause in the index
> exactly like above.  The problem is thus:

I thought PG could use an ordinary index for 'like' conditions with just a
terminating '%'?

My other thought is that like 'A%' should grab about 1/26th of the table
anyway (if the initial character distribution is random), and so a
sequential scan might be the best plan anyway...

M


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