Right now max_locks_per_transactions defines the average number of locks taken by a transaction. thus, shared memory is limited to max_locks_per_transaction * (max_connections + max_prepared_transactions). this is basically perfect. however, recently we have seen a couple of people having trouble with this. partitioned tables are becoming more and more popular so it is very likely that a single transaction can eat up a great deal of shared memory. some people having a lot of data create daily tables. if done for 3 years we already lost 1000 locks per inheritance-structure.

i wonder if it would make sense to split max_locks_per_transaction into two variables: max_locks (global size) and max_transaction_locks (local size). if set properly this would prevent "good" short running transactions from running out of shared memory when some "evil" long running transactions start to suck up shared memory.


if people find this useful we would glady implement this new feature for 8.3.

   many thanks,

      hans

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