[Twisted-Python] PyPgSQL not locking in adbapi

Jp Calderone exarkun at divmod.com
Wed Jun 1 17:05:22 EDT 2005

On Wed, 1 Jun 2005 16:27:54 -0300, Carolina Ardohain <carolinaardohain at gmail.com> wrote:
>I'm using Twisted 2.0, and pgSQL 2.4.
>I have two function in plpgsql that access the same table, I have to
>look if one id is in the table persons, if not then add to the table.
>I try to lock a table with "LOCK TABLE persons IN ACCESS EXCLUSIVE
>MODE;", so no both functions try to add the same id.
>I get 'duplicate key violates unique constraint' when run the two
>queries at the same time, if I delay one of the functions 1 sec then
>everything is fine.

What method did you use to run the LOCK statement?  Did you make sure it ran in the same transaction as the subsequent SELECT and UPDATE?

If you aren't already, I think you want to use one runInteraction() call for all three parts.


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