On Wed, Mar 30, 2005 at 02:30:58PM -0700, Michael Fuhr wrote: > I think Alvaro is working on a new locking mechanism that will allow > transactions to prevent a record from being modified without blocking > other transactions doing the same.
Yeah, and it does work. (I posted the patch two days ago.) alvherre=# create table a (a serial primary key); NOTICE: CREATE TABLE creará una secuencia implícita «a_a_seq» para la columna serial «a.a» NOTICE: CREATE TABLE / PRIMARY KEY creará el índice implícito «a_pkey» para la tabla «a» CREATE TABLE alvherre=# create table b (a int references a); CREATE TABLE alvherre=# insert into a default values; INSERT 0 1 alvherre=# insert into a default values; INSERT 0 1 alvherre=# begin; BEGIN alvherre=# insert into b values (1); INSERT 0 1 Session 2: alvherre=# begin; BEGIN alvherre=# insert into b values (2); INSERT 0 1 alvherre=# insert into b values (1); INSERT 0 1 Session 1: lvherre=# insert into b values (2); INSERT 0 1 alvherre=# commit; COMMIT Session 2: alvherre=# commit; COMMIT You'll notice if you do that on any released version it will deadlock ... Now this can't be applied right away because it's easy to run "out of memory" (shared memory for the lock table). Say, a delete or update that touches 10000 tuples does not work. I'm currently working on a proposal to allow the lock table to spill to disk ... -- Alvaro Herrera (<[EMAIL PROTECTED]>) "La persona que no quería pecar / estaba obligada a sentarse en duras y empinadas sillas / desprovistas, por cierto de blandos atenuantes" (Patricio Vogel) ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
