Re: Partitioning and constraint exclusion

[Melvin Davidson <melvin6925@xxxxxxxxx>]

First, what is the PostgresSQL version ??????

Next, in postgresql.conf, what is the value of constraint_exclusion ?

On Mon, Sep 7, 2015 at 8:55 AM, Jayadevan M <maymala.jayadevan@xxxxxxxxx> wrote:

Hello ,

I have a parent table and 6 child tables (partitions). The child tables have check constraints defined in the form

CHECK (myuid in (123,456,..)).

myuid is bigint, the constraints for the 6 child tables are definitely mutually exclusive. The number of values in the list ranges from 2-10 for 5 of the child tables. For the 6th child table, the list is 2500+ elements. When I try explain/explain analyze for even a simple query like

select * from parent where myuid in (123,456,789) 

the child table with 2500+ elements gets always scanned. I have an index on the column and that does get used. But why doesn't the planner just use constraint exclusion and not go for the index scan? Anyone faced a similar issue?

Thanks,

Jayadevan

--

Melvin Davidson
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