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Re: Lost updates vs resumable connections/transactions

From: Jan Wieck <JanWieck(at)Yahoo(dot)com>
To: Jens Lechtenboerger <lechten(at)wi(dot)uni-muenster(dot)de>
Cc: Greg Stark <gsstark(at)mit(dot)edu>, pgsql-interfaces(at)postgresql(dot)org
Subject: Re: Lost updates vs resumable connections/transactions
Date: 2004-12-17 16:17:37
Message-ID: 41C306A1.1070807@Yahoo.com (view raw or flat)
Thread:
Lists: pgsql-interfaces
On 12/17/2004 8:45 AM, Jens Lechtenboerger wrote:

> [...]
> When the connection is resumed, the postmaster creates a new socket
> with the (new) Apache process (just as you described above), gets
> the ID, informs the backend, and passes the new socket with
> sendmsg(2) to the backend which gets it with recvmsg(2).  (I have
> never passed sockets like this; I just read that it should work.)
> Now the backend can continue the existing transaction with the new
> Apache process.
> 
> Or not?

Yes, that would work ... on some but not all Unix derivates ... what 
about those where it does not? I know that Windows has a similar 
functionality available, but that would AFAIK require to use windows 
messages, which in turn requires to have a window handle for each and 
every backend, a rather dramatic change.

The PostgreSQL team members (me included) are big fans of portability. 
Introducing code that solves a problem for one specific web server, in 
the special case of a small number of application users, in a non 
portable way for only a couple operating systems and where the resulting 
functional difference is visible to the database client ... I don't 
think this idea has much of a chance to make it into the source tree.


Jan

-- 
#======================================================================#
# It's easier to get forgiveness for being wrong than for being right. #
# Let's break this rule - forgive me.                                  #
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Subject: Re: restore a plpgsql function with pg_restore
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Subject: Re: Lost updates vs resumable connections/transactions

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