Re: Changing the transaction isolation level within the stored

Hi, Mario,

Mario Splivalo wrote:
> Is it possible to change the transaction level within the procedure?

No, currently not, the PostgreSQL "stored procedures" really are "stored
functions" that are called inside a query, and thus cannot contain inner
transactions.

> I'm using Postgres 8.1.2 default isolation level. But, I would like one
> stored procedure to execute as in serializable isolation level. I have
> created my stored procedure like this:
[...]
> One thread (thread A) does this:
>
> 1. java got the message via http (whatever)
> 2. java does: begin;
> 3. java does: select * from create_message(...)
> 4. java does some checking
> 5. java does: select * from set_message_status(...)
> 6. java does some more checing
> 7. java does commit; (under rare circumstances java does rollback).

So you even want to change the transaction serialization level within a
running transaction? I'm sorry, this will not work, and I cannot think
of a sane way to make it work.

It is locically not possible to raise the isolation level when the
transaction was started with a lower level and thus may already have
irreversibly violated the constraits that the higher level wants to
guarantee.

HTH,
Markus
--
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf. | Software Development GIS

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