All good ideas, unfortunately, we can't change the inserting applicatin
code easily.
> -----Original Message-----
> From: Simon Riggs [mailto:simon@2ndquadrant.com]
> Sent: Tuesday, February 07, 2006 5:09 PM
> To: Marc Morin
> Cc: Markus Schaber; pgsql-performance@postgresql.org
> Subject: Re: [PERFORM] partitioning and locking problems
>
> On Thu, 2006-02-02 at 11:27 -0500, Marc Morin wrote:
>
> > > > 1- long running report is running on view
> > > > 2- continuous inserters into view into a table
> via a rule
> > > > 3- truncate or rule change occurs, taking an
> exclusive lock.
> > > > Must wait for #1 to finish.
> > > > 4- new reports and inserters must now wait for #3.
> > > > 5- now everyone is waiting for a single query
> in #1. Results
> > > > in loss of insert data granularity (important for our
> application).
>
> > Using a separate lock table is what we've decided to do in this
> > particular case to serialize #1 and #3. Inserters don't take this
> > lock and as such will not be stalled.
>
> Would it not be simpler to have the Inserters change from one
> table to another either upon command, on a fixed timing cycle
> or even better based upon one of the inserted values
> (Logdate?) (or all 3?). (Requires changes in the application
> layer: 3GL or db functions).
>
> The truncates can wait until the data has stopped being used.
>
> I'd be disinclined to using the locking system as a scheduling tool.
>
> Best Regards, Simon Riggs
>
>
>