Re: "select for update" confusion

on 3/21/04 5:10 PM, ken(at)perfect-image(dot)com purportedly said:

> I'm trying to build a type of record "check out" program and I'm just
> a wee bit confused.
> Several users will be using the same select
> statement at the same time and just want to make sure they're getting
> different records. example.......

AFAIK, Postgres does not have exclusive row-level locking. I.e., your SELECT
.. For UPDATE only locks writes, and not reads (SELECTs). You can only
accomplish exclusive locks with a table lock (LOCK TABLE), which should
guarantee serial execution of all concurrent queries, but with a possible
performance penalty depending on your application.

Keary Suska
Esoteritech, Inc.
"Leveraging Open Source for a better Internet"