INSERT ... SELECT FROM .... FOR UPDATE? - Mailing list pgsql-sql

From Mark Stosberg
Subject INSERT ... SELECT FROM .... FOR UPDATE?
Date
Msg-id e98e61$mrd$1@sea.gmane.org
Whole thread Raw
In response to Avoiding RI failure with INSERT ... SELECT FROM  (Mark Stosberg <mark@summersault.com>)
List pgsql-sql
Hello,

This is a re-phrasing of question I asked recently, inquiring about a
an approach I'm considering.

My query is:
> INSERT into item_hit_log (item_id, hit_date, hit_count)>    SELECT item_id, CURRENT_DATE + CAST('1 day' AS interval),
0>        FROM items where item_state = 'available';
 

The "items" table has a few hundred thousand rows in it, and is likely
to be updated by other queries while this runs.

The error we got last night was:
  ERROR:  insert or update on table "item_hit_log" violates foreign key
constraint "item_id_fk"  DETAIL:  Key (item_id)=(451226) is not present in table "items".

Re-running the transaction block a few minutes later worked.
 From reading the docs, it sounds like "SELECT ... FOR UPDATE"
might be the perfect solution here.

http://www.postgresql.org/docs/8.1/static/sql-select.html#SQL-FOR-UPDATE-SHARE

Since it's hard to test for this kind of failure, I wanted to get the
opinions of others here if this would be a good idea.

Thanks!
    Mark



pgsql-sql by date:

Previous
From: Aaron Bingham
Date:
Subject: Re: Can I do this smarter?
Next
From: "Stefan Arentz"
Date:
Subject: Querying for name/value pairs in reverse