Re: Extremely slow DELETE with cascade foreign keys - Mailing list pgsql-performance

From Tom Lane
Subject Re: Extremely slow DELETE with cascade foreign keys
Date
Msg-id 7973.1512491234@sss.pgh.pa.us
Whole thread Raw
In response to Extremely slow DELETE with cascade foreign keys  (Rodrigo Rosenfeld Rosas <rr.rosas@gmail.com>)
Responses Re: Extremely slow DELETE with cascade foreign keys
List pgsql-performance
Rodrigo Rosenfeld Rosas <rr.rosas@gmail.com> writes:
> Hi, I think something changed recently in my development environment as 
> I don't recall deletes being so slow before.
> I've created a new dump and restored to a new database, ran VACUUM FULL 
> ANALYSE and a simple delete takes forever as you can see here:

The usual suspect for this is not having an index on some FK referencing
column, thus forcing the FK check trigger to seq-scan the entire
referencing table for each referenced row that is to be deleted.

            regards, tom lane


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