Hi,

I have a very simple table:

CREATE TABLE PARAMS
(
  ID INTEGER NOT NULL,
  NAME VARCHAR(32) NOT NULL,
  CONSTRAINT PK_PARAMS PRIMARY KEY (ID),
  CONSTRAINT UNQ_PARAMS UNIQUE (NAME)
);


I have two threads which constantly and at the same time are writing to this table:

UPDATE OR INSERT INTO PARAMS (NAME) VALUES(:P_NAME) MATCHING (NAME) RETURNING ID;


I've set my transaction parameters like this:

FtraMain.TRParams.Add('isc_tpb_write');
FtraMain.TRParams.Add('isc_tpb_read_committed');
FtraMain.TRParams.Add('isc_tpb_wait');
FtraMain.TRParams.Add('isc_tpb_no_rec_version');

As far as I understand, such configuration should prevent deadlock exception to occur. However, deadlock still occurs from time to time:

Deadlock.
Deadlock.
Update conflicts with concurrent update.
Concurrent transaction number is 57258.


What am I doing wrong?

Thans for your assistance :)