Re: pg_dumpall - Mailing list pgsql-general

From Glyn Astill
Subject Re: pg_dumpall
Date
Msg-id 235223.76121.qm@web25809.mail.ukl.yahoo.com
Whole thread Raw
In response to Re: pg_dumpall  (Alvaro Herrera <alvherre@commandprompt.com>)
Responses Re: pg_dumpall
List pgsql-general
>Alvaro Herrera <alvherre@commandprompt.com> wrote:
> Glyn Astill wrote:
> > Out of interest, how does pg_dump manage to do a snapshot of a
> > database at an instant in time?
> >
> > My mental picture of pg_dump was just a series of queries dumping
> out
> > the tables...
>
> begin;
> set transaction isolation level serializable;
>
> --- begin dumping stuff;
>

Wouldn't that just lock everything so nothing could be updated? Or
just the table it is outputting?

I'm guessing I need to go off and school myself on different
isolation levels etc to understand, but say I have 2 tables "sales"
and "sold", and users are selling items with inserts into the sales
table and a count updating manually in sold. Wouldn't these end up
inconsistant in the dump?




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