Simon Riggs wrote:
@@ -3845,6 +3850,52 @@ sigusr1_handler(SIGNAL_ARGS)
PG_SETMASK(&BlockSig); + if (CheckPostmasterSignal(PMSIGNAL_RECOVERY_START))
+       {
+               Assert(pmState == PM_STARTUP);
+
+               /*
+                * Go to shutdown mode if a shutdown request was pending.
+                */
+               if (Shutdown > NoShutdown)
+               {
+                       pmState = PM_WAIT_BACKENDS;
+                       /* PostmasterStateMachine logic does the rest */
+               }
+               else
+               {
+                       /*
+                        * Startup process has entered recovery
+                        */
+                       pmState = PM_RECOVERY;


Hmm, I smell a race condition here:

1. Startup process goes into consistent state, and signals postmaster
2. Startup process finishes WAL replay and dies
3. Postmaster wakes up in reaper(), noting that the startup process dies, and goes into PM_RUN mode. 4. The above signal handler for postmaster is run, causing an assertion failure, or putting postmaster back into PM_RECOVERY mode if assertions are disabled.

Highly unlikely in practice, given how much code needs to run in the startup process between signaling the postmaster and exiting, but it seems theoretically possible. Do we care, and if we do, how can we fix it?

+
+                       /*
+                        * Load the flat authorization file into postmaster's ca
+                        * startup process won't have recomputed this from the d
+                        * yet, so it may change following recovery.
+                        */
+                       load_role();

Is there a race condition here too, if the startup process is writing the auth file at the same time? I guess we'd have the same problem with flat files in general, so maybe there's something else that mitigates the problem?

--
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com

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