On Thu, 2006-02-23 at 17:12 -0300, Carlos Henrique Reimer wrote: > When the pg_locks view is used the internal lock manager data > structures are momentarily locked and that is why I would like to know > if some application is reading the pg_locks view and how many times. > > Is there a way to discover it? AFAIK there is no easy way to determine this information. You could probably patch Postgres to record the info fairly easy: one way would be to allocate a small block of shared memory and an LWLock to protect it, and then have pg_lock_status() acquire the lock and increment a counter. Then add a new function to retrieve the current value of the counter. You could even do it without modifying the backend proper: change the definition of the pg_locks view to invoke a set-returning PL/PgSQL function. That function would increment a counter stored in some table, and then construct and return the normal pg_locks result set. -Neil
