On Thu, Jun 9, 2011 at 4:46 AM, Craig Ringer <craig@xxxxxxxxxxxxxxxxxxxxx> wrote: > On 9/06/2011 2:41 PM, Clemens Schwaighofer wrote: >> >> Hi, >> >> I have a plpgsql function where I read data from a table in a loop and >> update data in a different table. >> >> Is it possible to see the updated data from a different access during >> the run of this function? Or is this impossible because the function >> is a "transaction" and no data change is visible outside until the >> function is finished? I can see the changed data inside the function. > > (as far as I know) It's not possible for a function to see data committed by > other transactions since that function began executing, whether or not those > other transactions have committed. This is not correct. Yes, a snapshot is created, but that doesn't prevent you from seeing external changes. I have in fact many times relied on being able to block in a pl/pgsql loop and wait for a record to be set or something like that. If you don't want to deal with mid transaction changes, take out a lock or bump up to serializable. merlin -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
