Re: Guarantee order of batched pg_advisory_xact_lock

I just checked for hash collisions with the following query today:

SELECT COUNT(*), hashtextextended(key, 0) FROM
(
  SELECT key FROM table1
  UNION
  SELECT key FROM table2
  UNION
  ...
) keys (key)
GROUP BY hashtextextended(key, 0)
HAVING COUNT(*) > 1

Where table1, table2, ... are all the tables we are acquire keys from to use for the mentioned query.

Sadly, no results were returned. Thus, I can rule out hash collisions.

Any other thoughts? Here is an error log from the JDBC driver:

Nico Heller <nico.heller@posteo.de> writes:

So it would probably be better to ORDER BY the hashtextended result 
instead of :keysToLock, right?

Yeah, that seems like it'd work, if you have no other dependencies
on the locking order.
			regards, tom lane