Re: [ADMIN] Deadlock on transaction

On Mon, Feb 12, 2007 at 03:08:27PM -0300, Ezequias Rodrigues da Rocha wrote:
> I mean really deadlock. Other transactions can't access the database until
> the main transaction is complete.

What you describe sounds like a blocking lock: one transaction uses a
resource and another has to wait until it is not locked anymore

A deadlock is a special case: two transactions both need resources A and
B. transaction 1 locks A, and the next moment transaction 2 locks B. Now
transaction 1 waits for 2 to release B, but at the same time 2 waits for 1
to release A. This is called a deadlock, or circulair lock.
Postgresql automatically detects such a situation and rolls one of them
back. The client recieves a 'restartable database error' and that is
exactly true: ususally another try will work.

One method of fixing deadlocks is to make sure all your code accesses the
database in the same order. Alphabetically is easiest to remember...

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"Nothing is as subjective as reality"
Reinoud van Leeuwen reinoud(dot)v(at)n(dot)leeuwen(dot)net
http://www.xs4all.nl/~reinoud
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