Re: FOR SHARE vs FOR UPDATE locks

Simon Riggs <simon@2ndquadrant.com>

From: "Simon Riggs" <simon@2ndquadrant.com>
To: "Tom Lane" <tgl@sss.pgh.pa.us>
Cc: "Heikki Linnakangas" <heikki@enterprisedb.com>, "Alvaro Herrera" <alvherre@commandprompt.com>, <pgsql-hackers@postgresql.org>, <pgsql-core@postgresql.org>
Date: 2006-12-01T20:46:56Z
Lists: pgsql-hackers, pgsql-docs
On Fri, 2006-12-01 at 13:46 -0500, Tom Lane wrote:

> I'm also realizing that a fix along the throw-an-error line is
> nontrivial, eg, HeapTupleSatisfiesUpdate would need another return code.

Yes, thats starting to get hairy. The fix could easily break something
else in another corner of MVCC.

> So at this point we are facing three options:
> 	- throw in a large and poorly tested "fix" at the last moment;
> 	- postpone 8.2 until we can think of a real fix, which might
> 	  be a major undertaking;
> 	- ship 8.2 with the same behavior 8.0 and 8.1 had.
> None of these are very attractive, but I'm starting to think the last
> is the least bad.

The functionality in this area isn't yet complete anyway; we still have
locking in the partitioned table case to consider. It's not that bad
just to leave it as is. So last option gets my vote.

-- 
  Simon Riggs             
  EnterpriseDB   http://www.enterprisedb.com