Re: Guarantee order of batched pg_advisory_xact_lock

Does anyone have any idea what the root cause of my issue is? I appreciate any insight.
As I said, hash collisions can be rules out, sadly.

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:

org.postgresql.util.PSQLException: ERROR: deadlock detected Detail: Process 60780 waits for ExclusiveLock on advisory lock [24605,3030106527,494580150,1]; blocked by process 65280.                                                                                                                  Process 65280 waits for ExclusiveLock on advisory lock [24605,1321834016,1311356115,1]; blocked by process 60780.

On 2/11/26 23:49, Tom Lane wrote:

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