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

From: Marko Tiikkaja <marko(dot)tiikkaja(at)cs(dot)helsinki(dot)fi>
To: Greg Smith <greg(at)2ndquadrant(dot)com>
Cc: Boxuan Zhai <bxzhai2010(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Re: new patch of MERGE (merge_204) & a question about duplicated ctid
Date: 2010-12-30 02:45:31
Message-ID: 4D1BF24B.6000306@cs.helsinki.fi (view raw or flat)
Thread:
Lists: pgsql-hackers
On 2010-12-30 4:39 AM +0200, Greg Smith wrote:
> And that got me back again to concurrent testing.
>
> Moving onto next two problems...the basic MERGE feature seems to have
> stepped backwards a bit too.  I'm now seeing these quite often:
>
> ERROR:  duplicate key value violates unique constraint
> "pgbench_accounts_pkey"
> DETAIL:  Key (aid)=(176641) already exists.
> STATEMENT:  MERGE INTO pgbench_accounts t USING (SELECT 176641,1+(176641
> / 1000000)::integer,168,'') AS s(aid,bid,balance,filler) ON s.aid=t.aid
> WHEN MATCHED THEN UPDATE SET abalance=abalance + s.balance WHEN NOT
> MATCHED THEN INSERT VALUES(s.aid,s.bid,s.balance,s.filler);
>
> On my concurrent pgbench test, which had been working before.

I have no idea why it worked in the past, but the patch was never 
designed to work for UPSERT.  This has been discussed in the past and 
some people thought that that's not a huge deal.


Regards,
Marko Tiikkaja

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Subject: Re: Avoiding rewrite in ALTER TABLE ALTER TYPE
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Subject: Re: Re: new patch of MERGE (merge_204) & a question about duplicated ctid

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