Re: Update on true serializable techniques in MVCC - Mailing list pgsql-hackers

From Andres Freund
Subject Re: Update on true serializable techniques in MVCC
Date
Msg-id 200912161629.24399.andres@anarazel.de
Whole thread Raw
In response to Re: Update on true serializable techniques in MVCC  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: Update on true serializable techniques in MVCC  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
Moin,

On Wednesday 16 December 2009 16:24:42 Robert Haas wrote:
> >   Inserts and deletes follow the same protocol, obtaining an exclusive
> >   lock on the row after the one being inserted or deleted. The result
> >   of this locking protocol is that a range scan prevents concurrent
> >   inserts or delete within the range of the scan, and vice versa.
> >
> > That sounds like it should actually work.
> 
> Only if you can guarantee that the database will access the rows using
> some particular index.  If it gets to the data some other way it might
> accidentally circumvent the lock.  That's kind of a killer in terms of
> making this work for PostgreSQL.
Isnt the whole topic only relevant for writing access? There you have to 
access the index anyway.

Andres


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