Horton

Re: Re: new patch of MERGE (merge_204) & a question about duplicated ctid

Simon Riggs <simon@2ndquadrant.com>

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From: Simon Riggs <simon@2ndQuadrant.com>
To: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Stephen Frost <sfrost@snowman.net>, Greg Smith <greg@2ndquadrant.com>, Marko Tiikkaja <marko.tiikkaja@cs.helsinki.fi>, Boxuan Zhai <bxzhai2010@gmail.com>, pgsql-hackers@postgresql.org
Date: 2011-01-03T16:29:19Z
Lists: pgsql-hackers 
On Mon, 2011-01-03 at 18:08 +0200, Heikki Linnakangas wrote:

> It works in read committed mode, because you acquire a new snapshot 
> after the LOCK TABLE, and anyone else who modified the table must commit 
> before the lock is granted. In serializable mode you get a serialization 
> error.

If its not safe without this

LOCK TABLE ... IN SHARE ROW EXCLUSIVE MODE

then we should do that automatically, and document that.

-- 
 Simon Riggs           http://www.2ndQuadrant.com/books/
 PostgreSQL Development, 24x7 Support, Training and Services