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 6d098874d9b63a0aa0f66299fd48dc28b6caa279..0c6a4271a603cabf56489df1ca3baf31dcdb559d 100644 (file)
--- 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 */