From b33428d20c4b93869df5f8839433ea82885b9ac4 Mon Sep 17 00:00:00 2001
From: "Vadim B. Mikheev" <vadim4o@yahoo.com>
Date: Fri, 13 Oct 2000 12:06:40 +0000
Subject: [PATCH] Various utils for WAL
---
src/backend/access/transam/xlogutils.c | 120 +++++++++++++++++++++++++
1 file changed, 120 insertions(+)
create mode 100644 src/backend/access/transam/xlogutils.c
diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c
new file mode 100644
index 00000000000..8f44fabaa54
--- /dev/null
+++ b/src/backend/access/transam/xlogutils.c
@@ -0,0 +1,120 @@
+/*-------------------------------------------------------------------------
+ *
+ * xlog.c
+ *
+ *
+ * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/xlog.h"
+#include "access/xact.h"
+
+#ifdef XLOG
+
+/*
+ * Check if specified heap tuple was inserted by given
+ * xaction/command and return
+ *
+ * - -1 if not
+ * - 0 if there is no tuple at all
+ * - 1 if yes
+ */
+int
+XLogIsOwnerOfTuple(RelFileNode hnode, ItemPointer iptr,
+ TransactionId xid, CommandId cid)
+{
+ Relation reln;
+ Buffer buffer;
+ Page page;
+ ItemId lp;
+ HeapTupleHeader htup;
+
+ reln = XLogOpenRelation(false, RM_HEAP_ID, hnode);
+ if (!RelationIsValid(reln))
+ return(0);
+
+ buffer = ReadBuffer(reln, ItemPointerGetBlockNumber(iptr));
+ if (!BufferIsValid(buffer))
+ return(0);
+
+ LockBuffer(buffer, BUFFER_LOCK_SHARE);
+ page = (Page) BufferGetPage(buffer);
+ if (PageIsNew((PageHeader) page) ||
+ ItemPointerGetOffsetNumber(iptr) > PageGetMaxOffsetNumber(page))
+ {
+ UnlockAndReleaseBuffer(buffer);
+ return(0);
+ }
+ lp = PageGetItemId(page, ItemPointerGetOffsetNumber(iptr));
+ if (!ItemIdIsUsed(lp) || ItemIdDeleted(lp))
+ {
+ UnlockAndReleaseBuffer(buffer);
+ return(0);
+ }
+
+ htup = (HeapTupleHeader) PageGetItem(page, lp);
+
+ if (PageGetSUI(page) != ThisStartUpID || htup->t_xmin != xid || htup->t_cmin != cid)
+ {
+ UnlockAndReleaseBuffer(buffer);
+ return(-1);
+ }
+
+ UnlockAndReleaseBuffer(buffer);
+ return(1);
+}
+
+/*
+ * Check if exists valid (inserted by not aborted xaction) heap tuple
+ * for given item pointer
+ */
+bool
+XLogIsValidTuple(RelFileNode hnode, ItemPointer iptr)
+{
+ Relation reln;
+ Buffer buffer;
+ Page page;
+ ItemId lp;
+ HeapTupleHeader htup;
+
+ reln = XLogOpenRelation(false, RM_HEAP_ID, hnode);
+ if (!RelationIsValid(reln))
+ return(false);
+
+ buffer = ReadBuffer(reln, ItemPointerGetBlockNumber(iptr));
+ if (!BufferIsValid(buffer))
+ return(false);
+
+ LockBuffer(buffer, BUFFER_LOCK_SHARE);
+ page = (Page) BufferGetPage(buffer);
+ if (PageIsNew((PageHeader) page) ||
+ ItemPointerGetOffsetNumber(iptr) > PageGetMaxOffsetNumber(page))
+ {
+ UnlockAndReleaseBuffer(buffer);
+ return(false);
+ }
+ lp = PageGetItemId(page, ItemPointerGetOffsetNumber(iptr));
+ if (!ItemIdIsUsed(lp) || ItemIdDeleted(lp))
+ {
+ UnlockAndReleaseBuffer(buffer);
+ return(false);
+ }
+
+ htup = (HeapTupleHeader) PageGetItem(page, lp);
+
+ if (XLogIsAborted(PageGetSUI(page), htup->t_xmin))
+ {
+ UnlockAndReleaseBuffer(buffer);
+ return(false);
+ }
+
+ UnlockAndReleaseBuffer(buffer);
+ return(true);
+}
+
+#endif
--
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