Hi, I'm testing constraint exclusion on PostgreSQL 8.1 beta 1 on windows with
the GEOIP countries database and I have a few questions:
1. Can I say that an index created on the "parent" table is a "global" index,
an index that spans over data in all derived tables?
2. Can I say that an index created on any of the "child" or "inheriting"
table is a "partition" index, that spans data belonging that single table
only?
(explain plan seems to confirm that, just to be shure)
3. Constraint exclusion works (prunes child tables) only if your query
contains a condition based on the check constraint (say constraint "A") and
it doesn't get the fact that the data requested lies just in one child table
if the condition is on another column (say constraint "B"), even if "global"
and "partition" indexes are present for constraint "B"
Based on that quick look it would be great to add the ability for the
optimizer to find the "good" child table from a global index, which would
make "table partitioning" or "constraint exclusion" even more effective.
Hope what I wrote makes sense.
Best regards
paolo