View Single Post

   
  #7 (permalink)  
Old 04-15-2008, 09:54 PM
Chris Browne
 
Posts: n/a
Default Re: 2PC-induced lockup

tomas@tuxteam.de writes:
> On Wed, Jul 11, 2007 at 12:38:09AM -0400, Tom Lane wrote:
>> tomas@tuxteam.de writes:

> [...]
>> > It might make sense then to clear the pg_twophase directory on DB
>> > startup.

>>
>> <blink> I fear you have 100% misunderstood the point. The *only*
>> reason for that feature is to survive DB crashes.

>
> Ah -- so it is intentional that it keeps the DB from starting again.
> OK, then I misunderstood. Sorry for the noise.


I don't think that is so much "intentional" as it is an "emergent
property."

The usual point to 2PC is that once transactions are PREPAREd, they
*need* to be stored robustly enough to survive even a DB crash.

If one locks certain vital system resources, as part of that PREPAREd
transaction, that evidently causes some problems, alas...

The right resolution to this is not, a priori, evident yet.
--
(format nil "~S@~S" "cbbrowne" "linuxdatabases.info")
http://cbbrowne.com/info/linuxdistributions.html
Rules of the Evil Overlord #38. "If an enemy I have just killed has a
younger sibling or offspring anywhere, I will find them and have them
killed immediately, instead of waiting for them to grow up harboring
feelings of vengeance towards me in my old age."
<http://www.eviloverlord.com/>
Reply With Quote