Yep i already have those columns and unique constraint, my issue isn't sell
the seat two times, i was a lot of paranoiac about that and use a lock mode
to restricted for that.
I will check if i can create rows for seats before sell and use update, so i
can use SELECT FOR UPDATE and not use insert,
On Tue, Mar 01, 2011 at 09:23:49AM -0500, Alan Acosta wrote:
> seats have an specific bus even 5 minutes before departure, sometimes i know
> sometimes i don't, even sometimes when i know i have to change on fly this
> capacity, for example my bus crash just before departure, so i have to use a
>
ot
> made.
>
> David J.
>
> -Original Message-
> From: pgsql-general-ow...@postgresql.org
> [mailto:pgsql-general-ow...@postgresql.org] On Behalf Of Andrew Sullivan
> Sent: Monday, February 28, 2011 4:28 PM
> To: pgsql-general@postgresql.org
> Subject: Re
pgsql-general-ow...@postgresql.org] On Behalf Of Andrew Sullivan
Sent: Monday, February 28, 2011 4:28 PM
To: pgsql-general@postgresql.org
Subject: Re: [GENERAL] Lock ACCESS EXCLUSIVE and Select question !
On Mon, Feb 28, 2011 at 04:12:30PM -0500, Alan Acosta wrote:
> My application is trying to
On Mon, Feb 28, 2011 at 05:39:07PM -0500, Alan Acosta wrote:
> But i have a new problem there, i have no rows for update, i create new rows
> when the seats are sold, cause rarely the database knows the capacity of the
> bus, number of seats, even some bus doesn't have seat number 4 for example
> :
On Monday, February 28, 2011 2:39:07 pm Alan Acosta wrote:
> But i have a new problem there, i have no rows for update, i create new
> rows when the seats are sold, cause rarely the database knows the capacity
> of the bus, number of seats, even some bus doesn't have seat number 4 for
> example
So
Alan Acosta wrote:
> But i have a new problem there, i have no rows for update, i create new rows
> when the seats are sold, cause rarely the database knows the capacity of the
> bus, number of seats, even some bus doesn't have seat number 4 for example
> :p. So i cannot SELECT FOR UPDATE no existe
But i have a new problem there, i have no rows for update, i create new rows
when the seats are sold, cause rarely the database knows the capacity of the
bus, number of seats, even some bus doesn't have seat number 4 for example
:p. So i cannot SELECT FOR UPDATE no existent rows, but i still need t
On Mon, Feb 28, 2011 at 05:13:11PM -0500, Alan Acosta wrote:
> I really appreciate your help Andrew, and yep, i already starto to feel some
> pain lol. I suppose is true but is better to ask, SELECT FOR UPDATE is
> faster than LOCK ?
SELECT FOR UPDATE locks the row you're trying to lock. So it's
I really appreciate your help Andrew, and yep, i already starto to feel some
pain lol. I suppose is true but is better to ask, SELECT FOR UPDATE is
faster than LOCK ?
Thanks for the recommendations, i will check them ^_^
Cheers,
Alan Acosta
On Mon, Feb 28, 2011 at 4:28 PM, Andrew Sullivan wrote
On Mon, Feb 28, 2011 at 04:12:30PM -0500, Alan Acosta wrote:
> My application is trying to generate a numbered place for a client inside a
> bus, and to avoid to sell the place number "5" to two people, so i need to
> avoid that two sellers to sell the same place to same time, when i start my
> pr
My threads use each one different conecctions, so the transactions are
different, may be my bad English doesn't help to much, sorry for that !
My application is trying to generate a numbered place for a client inside a
bus, and to avoid to sell the place number "5" to two people, so i need to
avoi
On Mon, Feb 28, 2011 at 03:32:08PM -0500, Alan Acosta wrote:
> your recommendation about to use SHARE mode, but in
> http://www.postgresql.org/docs/8.3/static/explicit-locking.html i see that
> SHARE mode doesn't lock against itself, so, another thread using the same
> mode will be able to access t
Andrew, thank you very much for reply !
I already update my bookmark for 8.3 which is my current version,
http://www.postgresql.org/docs/8.3/static/explicit-locking.html, i see new
things here, like a comparative table.
Yep, seems like ACCESS EXCLUSIVE is a bad idea, at least now :p ! i check
you
On Mon, Feb 28, 2011 at 12:43:58PM -0500, Alan Acosta wrote:
> I'm using lock with ACCESS EXCLUSIVE in several of my tables to assure that
> only one process write in those tables at same time
Why are you doing that? It sounds like a bad idea to me.
But anyway, I believe that the SHARE lock (wh
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