Re: make MaxBackends available in _PG_init - Mailing list pgsql-hackers

On Tue, Feb 08, 2022 at 04:12:26PM -0500, Robert Haas wrote:
> After some investigation I've determined that it's no longer Friday
> afternoon. I also spent time investigating whether the patch had
> problems that would make me uncomfortable with the idea of committing
> it, and I did not find any. So, I committed it.

@@ -1641,8 +1642,8 @@ SignalBackends(void)
      * XXX in principle these pallocs could fail, which would be bad. Maybe
      * preallocate the arrays?  They're not that large, though.
      */
-    pids = (int32 *) palloc(MaxBackends * sizeof(int32));
-    ids = (BackendId *) palloc(MaxBackends * sizeof(BackendId));
+    pids = (int32 *) palloc(GetMaxBackends() * sizeof(int32));
+    ids = (BackendId *) palloc(GetMaxBackends() * sizeof(BackendId));

You could have optimized this one, while on it, as well as the ones in
pgstat_beinit() and pg_safe_snapshot_blocking_pids().  It is not hot,
but you did that for all the other callers of GetMaxBackends().  Just
saying..
--
Michael