] 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 generate a numbered place
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
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,
Hi everyone !
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, this is blocking my
SELECT, and this is what i want, but, deadlocks start to showing more and
more in my logs when SELECTS failt to get his Share Lock
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
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
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 the
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
avoid
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
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
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
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
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 existent
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
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
:p.
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 generate a numbered place for a client
inside a bus
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