Re: Query failed: ERROR: deadlock detected

thanks for the explanation... i found the mistake in a new pl/pgsql
function i wrote before this error occured;-)

Oliver Elphick wrote:
> On Mon, 2005-08-29 at 16:50 +0100, Aldor wrote:
>
>>PostgreSQL 8.0.3: Any idea what this is?
>>
>>---
>>Warning: pg_query(): Query failed: ERROR: deadlock detected
>>DETAIL: Process 8835 waits for ShareLock on transaction 193588236;
>>blocked by process 8834.
>>Process 8834 waits for ShareLock on transaction 193588228; blocked by
>>process 8835
>>---
>>
>>I have never seen such a log entry until now.
>
>
> You have two transactions locking each other out.
>
> For example:
> trans A: begin;
> trans B: begin;
> trans A: select * from table_a for update; -- locks table_a
> trans B: select * from table_b for update; -- locks table_b
> trans A: select * from table_b for update; -- blocked by trans B's lock
> trans B: select * from table_a for update; -- blocked by trans A's lock
>
> Since the two transactions are blocking each other, the locks will never
> be released by the transactions that are holding them. After a preset
> interval (about 1 second by default) a deadlock is detected and reported
> with this error message and one of the transactions is aborted.
>
> See manual section 12.3.3 in the 8.0 documentation.
>