Re: Using more tha one index per table

On Wed, Jul 21, 2010 at 1:58 AM, Rob Wultsch <wultsch(at)gmail(dot)com> wrote:
> On Wed, Jul 21, 2010 at 12:53 AM, A. Kretschmer
> <andreas(dot)kretschmer(at)schollglas(dot)com> wrote:
>>
>> In response to Elias Ghanem :
>> > Hi,
>> > I have a question concerning the uses of indexes in Postgresql.
>> > I red that in PG a query can not use more than one index per table: "a
>> > query or
>> > data manipulation command can use at most one index per table".
>>
>> That's not true, but it's true for MySQL, afaik.
>>
>
> That is not true either, though MySQL is less good at using bitmap'ed
> indexes. 5.0 can use "merge indexes",

Yeah, the biggest problem MySQL has is that it's got a pretty
simplistic query planner so it often makes poor choices.

Note that PostgreSQL on the other hand, has a much smarter query
planner. So it usually makes better choices. But when it makes a
wrong one, it can be a doozie. Luckily, reported strange behavior in
the query planner is usually fixed pretty quickly.