Re: Why is lock not released? - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Why is lock not released?
Date
Msg-id 10661.1124511818@sss.pgh.pa.us
Whole thread Raw
In response to Re: Why is lock not released?  (Alvaro Herrera <alvherre@alvh.no-ip.org>)
Responses Re: Why is lock not released?
List pgsql-hackers
Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
>> The "drop" way probably allows slightly more concurrency, but given that
>> people should seldom be taking exclusionary locks on system catalogs,
>> I'm not sure this is really an issue.

> Hmm.  The problem at hand (REASSIGN OWNED BY) may involve changing
> ownership of several objects in a single transaction.  The order is
> unspecified, because it's following a scan of the pg_shdepend entries --
> so it'd be easy for one REASSIGN OWNED BY transaction to deadlock with
> another one, if they happen to follow different orderings.

Uh, how is it going to deadlock on a lock that is not exclusive?
        regards, tom lane


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