Hi there, though this question has been asked several times before (but never really answered), I have to give it another try.
I have a multi-user application which synchronizes access to certain datasets via the database itself. If a user has a project in that application open no other user should be able to work on it too. When developing the application I considered the database to be a place to handle the synchronization since transactions are (normally) an integral part of a database system. When a user opens a project the application firstly locks a corresponding row. But since I don't want the application to block if that row is already locked I use the Oracle "NOWAIT" feature (SELECT ... FOR UPDATE NOWAIT) which tries to receive the lock on the specified row and if that row is already locked it returns with an error without blocking and I can tell the user that the project is already in use. Now that the application is to be ported to PG I need a similar functionality. Is there that an animal? If not, what would you recommend? TIA, - Jan. ---------------------------(end of broadcast)--------------------------- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match