Back-patch fix for bogus clearing of BufferDirtiedByMe.

tglsfdc · tglsfdc · commit 677972312637 · 2000-10-22T20:33:22.000Z
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.81.2.2 2000/10/04 07:50:00 inoue Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.81.2.3 2000/10/22 20:33:22 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1656,7 +1656,6 @@ ReleaseRelationBuffers(Relation rel)
 			}
 			/* Now we can do what we came for */
 			buf->flags &= ~(BM_DIRTY | BM_JUST_DIRTIED);
-			ClearBufferDirtiedByMe(i, buf);
 
 			/*
 			 * Release any refcount we may have.
@@ -1680,7 +1679,23 @@ ReleaseRelationBuffers(Relation rel)
 			 */
 			BufTableDelete(buf);
 		}
+
+		/*
+		 * Also check to see if BufferDirtiedByMe info for this buffer
+		 * refers to the target relation, and clear it if so.  This is
+		 * independent of whether the current contents of the buffer
+		 * belong to the target relation!
+		 *
+		 * NOTE: we have no way to clear BufferDirtiedByMe info in other
+		 * backends, but hopefully there are none with that bit set for
+		 * this rel, since we hold exclusive lock on this rel.
+		 */
+		if (BufferTagLastDirtied[i - 1].relId.relId == relid &&
+			(BufferTagLastDirtied[i - 1].relId.dbId == MyDatabaseId ||
+			 BufferTagLastDirtied[i - 1].relId.dbId == (Oid) NULL))
+			BufferDirtiedByMe[i - 1] = false;
 	}
+
 	SpinRelease(BufMgrLock);
 }
 
@@ -1726,7 +1741,6 @@ DropBuffers(Oid dbid)
 			}
 			/* Now we can do what we came for */
 			buf->flags &= ~(BM_DIRTY | BM_JUST_DIRTIED);
-			ClearBufferDirtiedByMe(i, buf);
 
 			/*
 			 * The thing should be free, if caller has checked that no
@@ -1738,7 +1752,20 @@ DropBuffers(Oid dbid)
 			 */
 			BufTableDelete(buf);
 		}
+
+		/*
+		 * Also check to see if BufferDirtiedByMe info for this buffer
+		 * refers to the target database, and clear it if so.  This is
+		 * independent of whether the current contents of the buffer
+		 * belong to the target database!
+		 *
+		 * (Actually, this is probably unnecessary, since I shouldn't have
+		 * ever dirtied pages of the target database, but...)
+		 */
+		if (BufferTagLastDirtied[i - 1].relId.dbId == dbid)
+			BufferDirtiedByMe[i - 1] = false;
 	}
+
 	SpinRelease(BufMgrLock);
 }
 
