Re: performance problems on Delete - Mailing list pgsql-admin

From Kevin Grittner
Subject Re: performance problems on Delete
Date
Msg-id 4C567A2E0200002500033FF1@gw.wicourts.gov
Whole thread Raw
In response to performance problems on Delete  (Silvio Brandani <silvio.brandani@tech.sdb.it>)
Responses Re: performance problems on Delete  (Silvio Brandani <silvio.brandani@tech.sdb.it>)
List pgsql-admin
Silvio Brandani  wrote:

> we have a performance issue on deleting data from a table.
>
> the delete is on the index key so should be very fast but the table
> have 13 contraints of type foreign keys and the slowness seems due
> to all the works done with the constraint.
> Trying to drop the constraint and execute the delete the result is
> immediate.

The usual reason for this is that you don't have indexes on the
referencing columns, so to check whether the delete is OK it has to
scan the related tables.  Think about what rows need to be checked to
determine whether the delete is allowed and index the columns which
will allow fast access to them.

-Kevin

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