> Seems to me that when there's a constant value in the query
> and an = comparision it will always be faster to use the (b-tree)
> index that's ordered first by the constant value, as then all further
> blocks are guarenteed to have a higher relevant information
> density.  At least when compared with another index that has the
> same columns in it.

That really depends on the stats.   Such a choice would *not* be 
appropriate if the < comparison was expected to return 1- rows while the = 
condition applied to 15% of the table.

What is your STATISTICS_TARGET for the relevant columns set to?   When's 
the last time you ran analyze?  If this is all updated, you want to post 
the pg_stats rows for the relevant columns?


Josh Berkus
Aglio Database Solutions
San Francisco

---------------------------(end of broadcast)---------------------------
TIP 7: don't forget to increase your free space map settings

Reply via email to