Hi, I've two threads countinuously updataing rows in the same table. Each one does: BEGIN, UPDATE,UPDATE,,,,COMMIT There can't be two active transactions updating the same row (my bug apart but I don't think so). I'm using default_transaction_isolation = 'serializable' I get "could not serialize access due to read/write dependencies among transactions" I din't expect to see it, hence there must be something in postgresql theory that I haven't understood well and I'd like a clarification.
Below here a log of commands issued by my threads followed by the error msg from PG server. Thanks Pupillo Log: thread 0: BEGIN thread 1: BEGIN thread 0: UPDATE stato SET dati=$1 WHERE id=0; thread 0: UPDATE stato SET dati=$1 WHERE id=1; thread 1: UPDATE stato SET dati=$1 WHERE id=10; thread 0: UPDATE stato SET dati=$1 WHERE id=2; thread 1: UPDATE stato SET dati=$1 WHERE id=11; thread 1: UPDATE stato SET dati=$1 WHERE id=12; thread 0: UPDATE stato SET dati=$1 WHERE id=3; thread 1: UPDATE stato SET dati=$1 WHERE id=13; thread 0: UPDATE stato SET dati=$1 WHERE id=4; thread 1: UPDATE stato SET dati=$1 WHERE id=14; thread 0: UPDATE stato SET dati=$1 WHERE id=5; thread 1: UPDATE stato SET dati=$1 WHERE id=15; thread 1: UPDATE stato SET dati=$1 WHERE id=16; thread 0: UPDATE stato SET dati=$1 WHERE id=6; thread 1: UPDATE stato SET dati=$1 WHERE id=17; thread 0: UPDATE stato SET dati=$1 WHERE id=7; thread 1: UPDATE stato SET dati=$1 WHERE id=18; thread 1: UPDATE stato SET dati=$1 WHERE id=19; thread 0: UPDATE stato SET dati=$1 WHERE id=8; thread 0: UPDATE stato SET dati=$1 WHERE id=9; thread 1: COMMIT thread 0:UPDATE ERROR ERROR: could not serialize access due to read/write dependencies among transactions DETAIL: Reason code: Canceled on identification as a pivot, during conflict out checking. HINT: The transaction might succeed if retried. STATEMENT: UPDATE stato SET dati=$1 WHERE id=9;
