Обсуждение: select locks table for updates
Hi
Does a select lock tables for updates?
No! Not in PostgreSQL.
However it is true for SQL Server.
Michel SALAIS
De : Yambu <hyambu@gmail.com>
Envoyé : jeudi 19 novembre 2020 11:07
À : Pgsql-admin <pgsql-admin@lists.postgresql.org>
Objet : select locks table for updates
Hi
Does a select lock tables for updates?
That depends on transaction isolation level. By default sql server doesn't use MVCC, so selects need shared locks. It's easily changed, though.
On Thu, 19 Nov 2020, 11:20 Michel SALAIS, <msalais@msym.fr> wrote:
No! Not in PostgreSQL.
However it is true for SQL Server.
Michel SALAIS
De : Yambu <hyambu@gmail.com>
Envoyé : jeudi 19 novembre 2020 11:07
À : Pgsql-admin <pgsql-admin@lists.postgresql.org>
Objet : select locks table for updates
Hi
Does a select lock tables for updates?
On Thu, 19 Nov 2020 at 10:20, Michel SALAIS <msalais@msym.fr> wrote: > > No! Not in PostgreSQL. In normal SELECTs, that is correct. If you use SELECT ... FOR UPDATE then rows will be locked. -- Simon Riggs http://www.EnterpriseDB.com/
I think the original question wasn't about what can be done. Any way that is how I considered it. A simple question, a simplereply taking into account default behavior only. The point was just to say that things don't go the same everywhere... Michel SALAIS -----Message d'origine----- De : Simon Riggs <simon@2ndquadrant.com> Envoyé : jeudi 19 novembre 2020 22:14 À : Michel SALAIS <msalais@msym.fr> Cc : Yambu <hyambu@gmail.com>; Pgsql-admin <pgsql-admin@lists.postgresql.org> Objet : Re: select locks table for updates On Thu, 19 Nov 2020 at 10:20, Michel SALAIS <msalais@msym.fr> wrote: > > No! Not in PostgreSQL. In normal SELECTs, that is correct. If you use SELECT ... FOR UPDATE then rows will be locked. -- Simon Riggs http://www.EnterpriseDB.com/