From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 7 May 2014 17:19:02 +0000 (-0400)
Subject: Never crash-and-restart for bgworkers without shared memory access.
X-Git-Tag: REL9_4_BETA1~39
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e2ce9aa27bf20eff2d991d0267a15ea5f7024cd7;p=postgresql

Never crash-and-restart for bgworkers without shared memory access.

The motivation for a crash and restart cycle when a backend dies is
that it might have corrupted shared memory on the way down; and we
can't recover reliably except by reinitializing everything.  But that
doesn't apply to processes that don't touch shared memory.  Currently,
there's nothing to prevent a background worker that doesn't request
shared memory access from touching shared memory anyway, but that's a
separate bug.

Previous to this commit, the coding in postmaster.c was inconsistent:
an exit status other than 0 or 1 didn't provoke a crash-and-restart,
but failure to release the postmaster child slot did.  This change
makes those cases consistent.
---

diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 6d098874d9..0c6a4271a6 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -2864,17 +2864,17 @@ CleanupBackgroundWorker(int pid,
 				HandleChildCrash(pid, exitstatus, namebuf);
 				return true;
 			}
-		}
 
-		if (!ReleasePostmasterChildSlot(rw->rw_child_slot))
-		{
-			/*
-			 * Uh-oh, the child failed to clean itself up.  Treat as a crash
-			 * after all.
-			 */
-			rw->rw_crashed_at = GetCurrentTimestamp();
-			HandleChildCrash(pid, exitstatus, namebuf);
-			return true;
+			if (!ReleasePostmasterChildSlot(rw->rw_child_slot))
+			{
+				/*
+				 * Uh-oh, the child failed to clean itself up.  Treat as a
+				 * crash after all.
+				 */
+				rw->rw_crashed_at = GetCurrentTimestamp();
+				HandleChildCrash(pid, exitstatus, namebuf);
+				return true;
+			}
 		}
 
 		/* Get it out of the BackendList and clear out remaining data */