Fix a memory leak in the autovacuum launcher code. Noted by Darcy Buskermolen,

who reported it privately to me.

diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 2a6e654269eafb054e7d19422fcaea78d736c6d3..ab77f004093cda9107bb85d38f9455c80560e3c0 100644 (file)
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -55,7 +55,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.57 2007/09/11 17:15:33 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.58 2007/09/12 22:14:59 alvherre Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1038,6 +1038,9 @@ do_start_worker(void)
    avw_dbase  *avdb;
    TimestampTz current_time;
    bool        skipit = false;
+   Oid         retval = InvalidOid;
+   MemoryContext tmpcxt,
+                 oldcxt;
 
    /* return quickly when there are no free workers */
    LWLockAcquire(AutovacuumLock, LW_SHARED);
@@ -1048,6 +1051,17 @@ do_start_worker(void)
    }
    LWLockRelease(AutovacuumLock);
 
+   /*
+    * Create and switch to a temporary context to avoid leaking the memory
+    * allocated for the database list.
+    */
+   tmpcxt = AllocSetContextCreate(CurrentMemoryContext,
+                                  "Start worker tmp cxt",
+                                  ALLOCSET_DEFAULT_MINSIZE,
+                                  ALLOCSET_DEFAULT_INITSIZE,
+                                  ALLOCSET_DEFAULT_MAXSIZE);
+   oldcxt = MemoryContextSwitchTo(tmpcxt);
+
    /* use fresh stats */
    pgstat_clear_snapshot();
 
@@ -1186,7 +1200,7 @@ do_start_worker(void)
 
        SendPostmasterSignal(PMSIGNAL_START_AUTOVAC_WORKER);
 
-       return avdb->adw_datid;
+       retval = avdb->adw_datid;
    }
    else if (skipit)
    {
@@ -1197,7 +1211,10 @@ do_start_worker(void)
        rebuild_database_list(InvalidOid);
    }
 
-   return InvalidOid;
+   MemoryContextSwitchTo(oldcxt);
+   MemoryContextDelete(tmpcxt);
+
+   return retval;
 }
 
 /*