Re: Select for update - Mailing list pgsql-sql

From David G. Johnston
Subject Re: Select for update
Date
Msg-id CAKFQuwaPC=DJA2LzfyhtMr-VAo55wPrwMBKQONNJ3W7Rws365A@mail.gmail.com
Whole thread Raw
In response to Re: Select for update  (Yambu <hyambu@gmail.com>)
Responses Re: Select for update  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-sql


On Wed, May 26, 2021, 08:20 Yambu <hyambu@gmail.com> wrote:
This update, sorry forgot to include FOR UPDATE part

UPDATE table1 set status_id=13 WHERE id= ( SELECT id FROM table2 where status_id=1 LIMIT 1 FOR UPDATE) RETURNING id into v_id;

On Wed, May 26, 2021 at 2:27 PM David G. Johnston <david.g.johnston@gmail.com> wrote:

On Wednesday, May 26, 2021, Yambu <hyambu@gmail.com> wrote:
Hello

May i know if i run the update below  if the row select in SELECT FOR UPDATE will not be available for selection during update?

UPDATE table1 set status_id=13 WHERE id= ( SELECT id FROM table2 where status_id=1 LIMIT 1) RETURNING id into v_id;

Which update?   The way it works is by locking - Ihe row is available but locked and may require waiting.

David J.

I don't think there is a point in saying for update when you are executing an update command.

David J.

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