Re: [SQL] Joining bug????

>Nice query. You mentioned having indexes on id columns etc. Are the
>indices
>single column, or multi-column? You may want to consider making some of
>them
>multi-column. The EXPLAIN does indicate usage of your indices, but it
>may not be
>optimal. If the distribution of your data in the indices is such that
>the each
>index scan must go through large chunks of data to qualify the other
>attributes in
>the join, it will run slow. By adding some well placed multi-part
>indices, the
>index scans will be narrower in their scan sets. Or not.
>
>Also, I could be wrong, but, I have found even batch loaded data needs a
>VACUUM
>ANALYZE to gather distributions statistics.
>
>pierre(at)desertmoon(dot)com wrote:
>
>> >

Thanks David. The vacuum analyze did the trick. I made the invalid
assumption that the statistics would be up to date just after a copy and
index creation. They were not. As soon as I ran the vacuum across all my
tables the explains changed and I got a MAJOR speed increase and the most
complicated query takes no more than 4-8 seconds. This is perfect.

Perhaps this (bug??) should be documented? I've seen documentation
relating to the vacuum analyze, but I always made that invalid
assumption. *sigh* Ah well you live and you learn. :)

-=pierre