RE: [HACKERS] MVCC works in serialized mode!

> -----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