Remove belt-and-suspenders guards against buffer pin leaks.

Forcibly releasing all leftover buffer pins should be unnecessary now
that we have a robust ResourceOwner mechanism, and it significantly
increases the cost of process shutdown.  Instead, in an assert-enabled
build, assert that no pins are held; in a non-assert-enabled build, do
nothing.

diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 54c7109..edc4977 100644 (file)
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -1659,31 +1659,26 @@ InitBufferPoolBackend(void)
 }
 
 /*
- * Ensure we have released all shared-buffer locks and pins during backend exit
+ * During backend exit, ensure that we released all shared-buffer locks and
+ * assert that we have no remaining pins.
  */
 static void
 AtProcExit_Buffers(int code, Datum arg)
 {
-       int                     i;
-
        AbortBufferIO();
        UnlockBuffers();
 
-       for (i = 0; i < NBuffers; i++)
+#ifdef USE_ASSERT_CHECKING
+       if (assert_enabled)
        {
-               if (PrivateRefCount[i] != 0)
-               {
-                       volatile BufferDesc *buf = &(BufferDescriptors[i]);
+               int                     i;
 
-                       /*
-                        * We don't worry about updating ResourceOwner; if we even got
-                        * here, it suggests that ResourceOwners are messed up.
-                        */
-                       PrivateRefCount[i] = 1;         /* make sure we release shared pin */
-                       UnpinBuffer(buf, false);
+               for (i = 0; i < NBuffers; i++)
+               {
                        Assert(PrivateRefCount[i] == 0);
                }
        }
+#endif
 
        /* localbuf.c needs a chance too */
        AtProcExit_LocalBuffers();

diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index 46fddde..059c7f1 100644 (file)
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -468,14 +468,23 @@ AtEOXact_LocalBuffers(bool isCommit)
 /*
  * AtProcExit_LocalBuffers - ensure we have dropped pins during backend exit.
  *
- * This is just like AtProcExit_Buffers, but for local buffers.  We have
- * to drop pins to ensure that any attempt to drop temp files doesn't
- * fail in DropRelFileNodeBuffers.
+ * This is just like AtProcExit_Buffers, but for local buffers.  We shouldn't
+ * be holding any remaining pins; if we are, and assertions aren't enabled,
+ * we'll fail later in DropRelFileNodeBuffers while trying to drop the temp
+ * rels.
  */
 void
 AtProcExit_LocalBuffers(void)
 {
-       /* just zero the refcounts ... */
-       if (LocalRefCount)
-               MemSet(LocalRefCount, 0, NLocBuffer * sizeof(*LocalRefCount));
+#ifdef USE_ASSERT_CHECKING
+       if (assert_enabled && LocalRefCount)
+       {
+               int                     i;
+
+               for (i = 0; i < NLocBuffer; i++)
+               {
+                       Assert(LocalRefCount[i] == 0);
+               }
+       }
+#endif
 }