Re: documentation about explicit locking - Mailing list pgsql-hackers

From Peter Eisentraut
Subject Re: documentation about explicit locking
Date
Msg-id 4643ae11-ef6e-e4be-e133-22885120bc59@2ndquadrant.com
Whole thread Raw
In response to Re: documentation about explicit locking  (Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>)
Responses Re: documentation about explicit locking  (Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>)
List pgsql-hackers
On 19/07/2018 06:17, Amit Langote wrote:
> When playing with this, I observed that a less user-friendly error message
> is emitted if multiple sessions race to create the same collation.
> 
> Session 1:
> begin;
> create collation collname (...);
> 
> Session 2:
> create collation collname (...);
> <blocks for lock on pg_collation>
> 
> Session 1:
> commit;
> 
> Session 2:
> ERROR:  duplicate key value violates unique constraint
> "pg_collation_name_enc_nsp_index"
> DETAIL:  Key (collname, collencoding, collnamespace)=(collname, 6, 2200)
> already exists.

You get the same behavior with for example CREATE FUNCTION or CREATE
TYPE.  I don't think we need to fix this specifically for CREATE COLLATION.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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