Minor code cleanup in bufmgr.c and bufmgr.h, mainly by moving repeated

lines of code into internal routines (drop_relfilenode_buffers,
release_buffer) and by hiding unused routines (PrintBufferDescs,
PrintPinnedBufs) behind #ifdef NOT_USED. Remove AbortBufferIO()
declaration from bufmgr.c (already declared in bufmgr.h)

Manfred Koizar

diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 1a86afb286e12a21a7c5b7b3dd82f8aeec5a9cdf..b2c19e99f47b48ac439a9d5c73810a0ddc8a4793 100644 (file)
--- 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 1.126 2002/06/20 20:29:34 momjian Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.127 2002/07/02 05:47:37 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -71,7 +71,6 @@ static void WaitIO(BufferDesc *buf);
 static void StartBufferIO(BufferDesc *buf, bool forInput);
 static void TerminateBufferIO(BufferDesc *buf);
 static void ContinueBufferIO(BufferDesc *buf, bool forInput);
-extern void AbortBufferIO(void);
 
 /*
  * Macro : BUFFER_IS_BROKEN
@@ -85,9 +84,14 @@ static BufferDesc *BufferAlloc(Relation reln, BlockNumber blockNum,
            bool *foundPtr);
 static int ReleaseBufferWithBufferLock(Buffer buffer);
 static int BufferReplace(BufferDesc *bufHdr);
+#ifdef NOT_USED
 void       PrintBufferDescs(void);
+#endif
 
 static void write_buffer(Buffer buffer, bool unpin);
+static void drop_relfilenode_buffers(RelFileNode rnode,
+                                     bool do_local, bool do_both);
+static int release_buffer(Buffer buffer, bool havelock);
 
 /*
  * ReadBuffer -- returns a buffer containing the requested
@@ -1097,34 +1101,26 @@ RelationGetNumberOfBlocks(Relation relation)
    return relation->rd_nblocks;
 }
 
-/* ---------------------------------------------------------------------
- *     DropRelationBuffers
- *
- *     This function removes all the buffered pages for a relation
- *     from the buffer pool.  Dirty pages are simply dropped, without
- *     bothering to write them out first.  This is NOT rollback-able,
- *     and so should be used only with extreme caution!
- *
- *     We assume that the caller holds an exclusive lock on the relation,
- *     which should assure that no new buffers will be acquired for the rel
- *     meanwhile.
+/*
+ * drop_relfilenode_buffers -- common functionality for
+ *                             DropRelationBuffers and
+ *                             DropRelFileNodeBuffers
  *
  *     XXX currently it sequentially searches the buffer pool, should be
  *     changed to more clever ways of searching.
- * --------------------------------------------------------------------
  */
-void
-DropRelationBuffers(Relation rel)
+static void
+drop_relfilenode_buffers(RelFileNode rnode, bool do_local, bool do_both)
 {
    int         i;
    BufferDesc *bufHdr;
 
-   if (rel->rd_myxactonly)
+   if (do_local)
    {
        for (i = 0; i < NLocBuffer; i++)
        {
            bufHdr = &LocalBufferDescriptors[i];
-           if (RelFileNodeEquals(bufHdr->tag.rnode, rel->rd_node))
+           if (RelFileNodeEquals(bufHdr->tag.rnode, rnode))
            {
                bufHdr->flags &= ~(BM_DIRTY | BM_JUST_DIRTIED);
                bufHdr->cntxDirty = false;
@@ -1132,7 +1128,8 @@ DropRelationBuffers(Relation rel)
                bufHdr->tag.rnode.relNode = InvalidOid;
            }
        }
-       return;
+       if (!do_both)
+           return;
    }
 
    LWLockAcquire(BufMgrLock, LW_EXCLUSIVE);
@@ -1141,7 +1138,7 @@ DropRelationBuffers(Relation rel)
    {
        bufHdr = &BufferDescriptors[i - 1];
 recheck:
-       if (RelFileNodeEquals(bufHdr->tag.rnode, rel->rd_node))
+       if (RelFileNodeEquals(bufHdr->tag.rnode, rnode))
        {
            /*
             * If there is I/O in progress, better wait till it's done;
@@ -1187,6 +1184,25 @@ recheck:
    LWLockRelease(BufMgrLock);
 }
 
+/* ---------------------------------------------------------------------
+ *     DropRelationBuffers
+ *
+ *     This function removes all the buffered pages for a relation
+ *     from the buffer pool.  Dirty pages are simply dropped, without
+ *     bothering to write them out first.  This is NOT rollback-able,
+ *     and so should be used only with extreme caution!
+ *
+ *     We assume that the caller holds an exclusive lock on the relation,
+ *     which should assure that no new buffers will be acquired for the rel
+ *     meanwhile.
+ * --------------------------------------------------------------------
+ */
+void
+DropRelationBuffers(Relation rel)
+{
+   drop_relfilenode_buffers(rel->rd_node, rel->rd_myxactonly, false);
+}
+
 /* ---------------------------------------------------------------------
  *     DropRelFileNodeBuffers
  *
@@ -1201,73 +1217,8 @@ recheck:
 void
 DropRelFileNodeBuffers(RelFileNode rnode)
 {
-   int         i;
-   BufferDesc *bufHdr;
-
    /* We have to search both local and shared buffers... */
-
-   for (i = 0; i < NLocBuffer; i++)
-   {
-       bufHdr = &LocalBufferDescriptors[i];
-       if (RelFileNodeEquals(bufHdr->tag.rnode, rnode))
-       {
-           bufHdr->flags &= ~(BM_DIRTY | BM_JUST_DIRTIED);
-           bufHdr->cntxDirty = false;
-           LocalRefCount[i] = 0;
-           bufHdr->tag.rnode.relNode = InvalidOid;
-       }
-   }
-
-   LWLockAcquire(BufMgrLock, LW_EXCLUSIVE);
-
-   for (i = 1; i <= NBuffers; i++)
-   {
-       bufHdr = &BufferDescriptors[i - 1];
-recheck:
-       if (RelFileNodeEquals(bufHdr->tag.rnode, rnode))
-       {
-           /*
-            * If there is I/O in progress, better wait till it's done;
-            * don't want to delete the relation out from under someone
-            * who's just trying to flush the buffer!
-            */
-           if (bufHdr->flags & BM_IO_IN_PROGRESS)
-           {
-               WaitIO(bufHdr);
-
-               /*
-                * By now, the buffer very possibly belongs to some other
-                * rel, so check again before proceeding.
-                */
-               goto recheck;
-           }
-           /* Now we can do what we came for */
-           bufHdr->flags &= ~(BM_DIRTY | BM_JUST_DIRTIED);
-           bufHdr->cntxDirty = false;
-
-           /*
-            * Release any refcount we may have.
-            *
-            * This is very probably dead code, and if it isn't then it's
-            * probably wrong.  I added the Assert to find out --- tgl
-            * 11/99.
-            */
-           if (!(bufHdr->flags & BM_FREE))
-           {
-               /* Assert checks that buffer will actually get freed! */
-               Assert(PrivateRefCount[i - 1] == 1 &&
-                      bufHdr->refcount == 1);
-               ReleaseBufferWithBufferLock(i);
-           }
-
-           /*
-            * And mark the buffer as no longer occupied by this rel.
-            */
-           BufTableDelete(bufHdr);
-       }
-   }
-
-   LWLockRelease(BufMgrLock);
+   drop_relfilenode_buffers(rnode, true, true);
 }
 
 /* ---------------------------------------------------------------------
@@ -1343,6 +1294,7 @@ recheck:
  *     use only.
  * -----------------------------------------------------------------
  */
+#ifdef NOT_USED
 void
 PrintBufferDescs()
 {
@@ -1375,7 +1327,9 @@ blockNum=%u, flags=0x%x, refcount=%d %ld)",
        }
    }
 }
+#endif
 
+#ifdef NOT_USED
 void
 PrintPinnedBufs()
 {
@@ -1395,6 +1349,7 @@ blockNum=%u, flags=0x%x, refcount=%d %ld)",
    }
    LWLockRelease(BufMgrLock);
 }
+#endif
 
 /*
  * BufferPoolBlowaway
@@ -1589,14 +1544,12 @@ FlushRelationBuffers(Relation rel, BlockNumber firstDelBlock)
    return 0;
 }
 
-#undef ReleaseBuffer
-
 /*
- * ReleaseBuffer -- remove the pin on a buffer without
- *     marking it dirty.
+ * release_buffer -- common functionality for
+ *                   ReleaseBuffer and ReleaseBufferWithBufferLock
  */
-int
-ReleaseBuffer(Buffer buffer)
+static int
+release_buffer(Buffer buffer, bool havelock)
 {
    BufferDesc *bufHdr;
 
@@ -1617,14 +1570,30 @@ ReleaseBuffer(Buffer buffer)
        PrivateRefCount[buffer - 1]--;
    else
    {
-       LWLockAcquire(BufMgrLock, LW_EXCLUSIVE);
+       if (!havelock)
+           LWLockAcquire(BufMgrLock, LW_EXCLUSIVE);
+
        UnpinBuffer(bufHdr);
-       LWLockRelease(BufMgrLock);
+
+       if (!havelock)
+           LWLockRelease(BufMgrLock);
    }
 
    return STATUS_OK;
 }
 
+#undef ReleaseBuffer
+
+/*
+ * ReleaseBuffer -- remove the pin on a buffer without
+ *     marking it dirty.
+ */
+int
+ReleaseBuffer(Buffer buffer)
+{
+   return release_buffer(buffer, false);
+}
+
 /*
  * ReleaseBufferWithBufferLock
  *     Same as ReleaseBuffer except we hold the bufmgr lock
@@ -1632,27 +1601,7 @@ ReleaseBuffer(Buffer buffer)
 static int
 ReleaseBufferWithBufferLock(Buffer buffer)
 {
-   BufferDesc *bufHdr;
-
-   if (BufferIsLocal(buffer))
-   {
-       Assert(LocalRefCount[-buffer - 1] > 0);
-       LocalRefCount[-buffer - 1]--;
-       return STATUS_OK;
-   }
-
-   if (BAD_BUFFER_ID(buffer))
-       return STATUS_ERROR;
-
-   bufHdr = &BufferDescriptors[buffer - 1];
-
-   Assert(PrivateRefCount[buffer - 1] > 0);
-   if (PrivateRefCount[buffer - 1] > 1)
-       PrivateRefCount[buffer - 1]--;
-   else
-       UnpinBuffer(bufHdr);
-
-   return STATUS_OK;
+   return release_buffer(buffer, true);
 }
 
 
@@ -1695,7 +1644,7 @@ refcount = %ld, file: %s, line: %d\n",
 #endif
 
 #ifdef NOT_USED
-int
+Buffer
 ReleaseAndReadBuffer_Debug(char *file,
                           int line,
                           Buffer buffer,
@@ -2117,7 +2066,7 @@ TerminateBufferIO(BufferDesc *buf)
 {
    Assert(buf == InProgressBuf);
    LWLockRelease(buf->io_in_progress_lock);
-   InProgressBuf = (BufferDesc *) 0;
+   InProgressBuf = (BufferDesc *) NULL;
 }
 
 /*
@@ -2142,7 +2091,7 @@ ContinueBufferIO(BufferDesc *buf, bool forInput)
 void
 InitBufferIO(void)
 {
-   InProgressBuf = (BufferDesc *) 0;
+   InProgressBuf = (BufferDesc *) NULL;
 }
 #endif
 

diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h
index 825033974a6eb3f43a2f559d7b8b858c35a74cd2..a6952fa1f69cb921ab36096469393e62a5c25dfa 100644 (file)
--- a/src/include/storage/bufmgr.h
+++ b/src/include/storage/bufmgr.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: bufmgr.h,v 1.60 2002/06/20 20:29:52 momjian Exp $
+ * $Id: bufmgr.h,v 1.61 2002/07/02 05:47:37 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -167,7 +167,9 @@ extern int  FlushRelationBuffers(Relation rel, BlockNumber firstDelBlock);
 extern void DropRelationBuffers(Relation rel);
 extern void DropRelFileNodeBuffers(RelFileNode rnode);
 extern void DropBuffers(Oid dbid);
+#ifdef NOT_USED
 extern void PrintPinnedBufs(void);
+#endif
 extern int BufferShmemSize(void);
 extern RelFileNode BufferGetFileNode(Buffer buffer);