"Robins Tharakan" <tharakan@xxxxxxxxx> writes: > Would it fine to consider that an UPDATE query that found no records to > update is (performance wise) the same as a SELECT query with the same WHERE > clause ? > As in, does an UPDATE query perform additional overhead even before it finds > the record to work on ? The UPDATE would fire BEFORE STATEMENT and AFTER STATEMENT triggers, if there are any. Also, it would take a slightly stronger lock on the table, which might result in blocking either the UPDATE itself or some concurrent query where a plain SELECT would not've. There might be some other corner cases I've forgotten. But in the basic case I think your assumption is correct. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
