Skip site navigation (1) Skip section navigation (2)

RE: [HACKERS] MVCC works in serialized mode!

From: "Hiroshi Inoue" <Inoue(at)tpf(dot)co(dot)jp>
To: "Vadim Mikheev" <vadim(at)krs(dot)ru>
Cc: <hackers(at)postgreSQL(dot)org>
Subject: RE: [HACKERS] MVCC works in serialized mode!
Date: 1998-12-25 06:09:04
Message-ID: 000001be2fcd$12b05620$2801007e@cadzone.tpf.co.jp (view raw or flat)
Thread:
Lists: pgsql-hackers
> -----Original Message-----
> From: root(at)dune(dot)krs(dot)ru [mailto:root(at)dune(dot)krs(dot)ru]On Behalf Of Vadim
> Mikheev
> Sent: Friday, December 25, 1998 2:40 PM
> To: Hiroshi Inoue
> Cc: hackers(at)postgreSQL(dot)org
> Subject: Re: [HACKERS] MVCC works in serialized mode!
>
>
> Hiroshi Inoue wrote:
> >
> > >
> > > CVS is just updated...
> > >
> > > Please try concurrent writes/reads...
> > >
> >
> > I happend to enjoy MVCC a little in (v6.4.1) .
> >
> > Readers are never blocked and writers are blocked only by
> > same row writers as I expected.
> > It's so comfortable.
> >
> > But I have a question.
> > Once transactions are blocked,it takes so long time to resume
> > after blocks were removed.
> > Why ?
> > Currently blocked transactions resume immediately after blocks
> > were removed.
>
> What do you mean?
> Example please...
>

inoue=> create table t1 (key int,a int);
inoue=> insert into t1 values (1,0);

<Session-1>                                          <Session-2>

inoue=> begin;                                       inoue=> begin;
BEGIN                                                   BEGIN
inoue=> update t1 set a=1 where key=1;
UPDATE 1
                                                            inoue=> update
t1 set a=2 where key=1;


                                                                 [ blocked ]
inoue=> end/abort;
END/ABORT
                                                                   [ after
long time .... ]
                                                            ERROR:  Can't
serialize access due to concurrent update
                                                            / UPDATE 1


Thanks.

Hiroshi Inoue
Inoue(at)tpf(dot)co(dot)jp


In response to

Responses

pgsql-hackers by date

Next:From: Vadim MikheevDate: 1998-12-25 08:06:40
Subject: Re: [HACKERS] MVCC works in serialized mode!
Previous:From: Vadim MikheevDate: 1998-12-25 05:39:32
Subject: Re: [HACKERS] MVCC works in serialized mode!

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group