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Re: Hot standby, recovery procs

From: Simon Riggs <simon(at)2ndQuadrant(dot)com>
To: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Hot standby, recovery procs
Date: 2009-02-24 20:25:28
Message-ID: 1235507128.16176.228.camel@ebony.2ndQuadrant (view raw or flat)
Thread:
Lists: pgsql-hackers
On Tue, 2009-02-24 at 21:59 +0200, Heikki Linnakangas wrote:
> We only need the lsn atrribute because we when we take the snapshot
> of 
> running xids, we don't write it to the WAL immediately, and a new 
> transaction might begin after that. If we close that gap in the
> master, 
> we don't need the lsn in recovery procs.
> 
> Actually, I think the patch doesn't get that right as it stands:
> 
> 0. Transactions 1 is running in master
> 1. Get list of running transactions
> 2. Transaction 1 commits.
> 3. List of running xacts is written to WAL
> 
> When the standby replays the xl_running_xacts record, it will create
> a 
> recovery proc and mark the transaction as running again, even though
> it 
> has already committed.

No, because we check whether TransactionIdDidCommit().

-- 
 Simon Riggs           www.2ndQuadrant.com
 PostgreSQL Training, Services and Support


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Next:From: Heikki LinnakangasDate: 2009-02-24 20:29:04
Subject: Re: Hot standby, recovery procs
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Subject: Re: Synchronous replication & Hot standby patches

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