Re: WriteBuffer return value

On Wed, 12 Jun 2002 10:19:17 -0400, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>I'd vote for changing WriteBuffer to
>return void, and have it elog() on bad argument.

Whatever you want ...
BTW, to avoid rejected hunks this patch should be applied after the
EliminateUnused patch I posted 2002-06-10.

diff -ur ../orig/src/backend/commands/sequence.c src/backend/commands/sequence.c
--- ../orig/src/backend/commands/sequence.c 2002-06-10 15:40:46.000000000 +0200
+++ src/backend/commands/sequence.c 2002-06-13 09:32:25.000000000 +0200
@@ -468,8 +468,7 @@

LockBuffer(buf, BUFFER_LOCK_UNLOCK);

- if (WriteBuffer(buf) == STATUS_ERROR)
- elog(ERROR, "%s.nextval: WriteBuffer failed", sequence->relname);
+ WriteBuffer(buf);

relation_close(seqrel, NoLock);

@@ -581,8 +580,7 @@

LockBuffer(buf, BUFFER_LOCK_UNLOCK);

- if (WriteBuffer(buf) == STATUS_ERROR)
- elog(ERROR, "%s.setval: WriteBuffer failed", sequence->relname);
+ WriteBuffer(buf);

relation_close(seqrel, NoLock);
}
diff -ur ../orig/src/backend/storage/buffer/bufmgr.c src/backend/storage/buffer/bufmgr.c
--- ../orig/src/backend/storage/buffer/bufmgr.c 2002-06-10 15:00:57.000000000 +0200
+++ src/backend/storage/buffer/bufmgr.c 2002-06-13 09:32:40.000000000 +0200
@@ -87,6 +87,7 @@
static int BufferReplace(BufferDesc *bufHdr);
void PrintBufferDescs(void);

+static void write_buffer(Buffer buffer, bool unpin);

/*
* ReadBuffer -- returns a buffer containing the requested
@@ -558,29 +559,22 @@
}

/*
- * WriteBuffer
- *
- * Marks buffer contents as dirty (actual write happens later).
- *
- * Assume that buffer is pinned. Assume that reln is
- * valid.
- *
- * Side Effects:
- * Pin count is decremented.
+ * write_buffer -- common functionality for
+ * WriteBuffer and WriteNoReleaseBuffer
*/
-
-#undef WriteBuffer
-
-int
-WriteBuffer(Buffer buffer)
+static void
+write_buffer(Buffer buffer, bool release)
{
BufferDesc *bufHdr;

if (BufferIsLocal(buffer))
- return WriteLocalBuffer(buffer, TRUE);
+ {
+ WriteLocalBuffer(buffer, release);
+ return;
+ }

if (BAD_BUFFER_ID(buffer))
- return FALSE;
+ elog(ERROR, "write_buffer: bad buffer %d", buffer);

bufHdr = &BufferDescriptors[buffer - 1];

@@ -589,37 +583,39 @@

bufHdr->flags |= (BM_DIRTY | BM_JUST_DIRTIED);

- UnpinBuffer(bufHdr);
+ if (release)
+ UnpinBuffer(bufHdr);
LWLockRelease(BufMgrLock);
+}

- return TRUE;
+/*
+ * WriteBuffer
+ *
+ * Marks buffer contents as dirty (actual write happens later).
+ *
+ * Assume that buffer is pinned. Assume that reln is
+ * valid.
+ *
+ * Side Effects:
+ * Pin count is decremented.
+ */
+
+#undef WriteBuffer
+
+void
+WriteBuffer(Buffer buffer)
+{
+ write_buffer(buffer, true);
}

/*
* WriteNoReleaseBuffer -- like WriteBuffer, but do not unpin the buffer
* when the operation is complete.
*/
-int
+void
WriteNoReleaseBuffer(Buffer buffer)
{
- BufferDesc *bufHdr;
-
- if (BufferIsLocal(buffer))
- return WriteLocalBuffer(buffer, FALSE);
-
- if (BAD_BUFFER_ID(buffer))
- return STATUS_ERROR;
-
- bufHdr = &BufferDescriptors[buffer - 1];
-
- LWLockAcquire(BufMgrLock, LW_EXCLUSIVE);
- Assert(bufHdr->refcount > 0);
-
- bufHdr->flags |= (BM_DIRTY | BM_JUST_DIRTIED);
-
- LWLockRelease(BufMgrLock);
-
- return STATUS_OK;
+ write_buffer(buffer, false);
}


diff -ur ../orig/src/backend/storage/buffer/localbuf.c src/backend/storage/buffer/localbuf.c
--- ../orig/src/backend/storage/buffer/localbuf.c 2002-05-03 19:42:11.000000000 +0200
+++ src/backend/storage/buffer/localbuf.c 2002-06-13 09:23:56.000000000 +0200
@@ -155,7 +155,7 @@
* WriteLocalBuffer -
* writes out a local buffer
*/
-int
+void
WriteLocalBuffer(Buffer buffer, bool release)
{
int bufid;
@@ -174,8 +174,6 @@
Assert(LocalRefCount[bufid] > 0);
LocalRefCount[bufid]--;
}
-
- return true;
}

/*
diff -ur ../orig/src/include/storage/buf_internals.h src/include/storage/buf_internals.h
--- ../orig/src/include/storage/buf_internals.h 2002-06-10 15:03:44.000000000 +0200
+++ src/include/storage/buf_internals.h 2002-06-13 09:23:26.000000000 +0200
@@ -176,7 +176,7 @@

extern BufferDesc *LocalBufferAlloc(Relation reln, BlockNumber blockNum,
bool *foundPtr);
-extern int WriteLocalBuffer(Buffer buffer, bool release);
+extern void WriteLocalBuffer(Buffer buffer, bool release);
extern int FlushLocalBuffer(Buffer buffer, bool sync, bool release);
extern void LocalBufferSync(void);
extern void ResetLocalBufferPool(void);
diff -ur ../orig/src/include/storage/bufmgr.h src/include/storage/bufmgr.h
--- ../orig/src/include/storage/bufmgr.h 2002-04-16 01:47:12.000000000 +0200
+++ src/include/storage/bufmgr.h 2002-06-13 09:22:59.000000000 +0200
@@ -148,8 +148,8 @@
*/
extern Buffer ReadBuffer(Relation reln, BlockNumber blockNum);
extern int ReleaseBuffer(Buffer buffer);
-extern int WriteBuffer(Buffer buffer);
-extern int WriteNoReleaseBuffer(Buffer buffer);
+extern void WriteBuffer(Buffer buffer);
+extern void WriteNoReleaseBuffer(Buffer buffer);
extern Buffer ReleaseAndReadBuffer(Buffer buffer, Relation relation,
BlockNumber blockNum);
extern int FlushBuffer(Buffer buffer, bool sync, bool release);