From 2589735da08c4e597accb6eab5ae65b6339ee630 Mon Sep 17 00:00:00 2001
From: Tom Lane
Date: Sat, 25 Aug 2001 18:52:43 +0000
Subject: Replace implementation of pg_log as a relation accessed through the
 buffer manager with 'pg_clog', a specialized access method modeled on
 pg_xlog.  This simplifies startup (don't need to play games to open pg_log;
 among other things, OverrideTransactionSystem goes away), should improve
 performance a little, and opens the door to recycling commit log space by
 removing no-longer-needed segments of the commit log.  Actual recycling is
 not there yet, but I felt I should commit this part separately since it'd
 still be useful if we chose not to do transaction ID wraparound.

---
 src/include/access/clog.h | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 src/include/access/clog.h

(limited to 'src/include/access/clog.h')

diff --git a/src/include/access/clog.h b/src/include/access/clog.h
new file mode 100644
index 00000000000..4e44e8036cf
--- /dev/null
+++ b/src/include/access/clog.h
@@ -0,0 +1,47 @@
+/*
+ * clog.h
+ *
+ * PostgreSQL transaction-commit-log manager
+ *
+ * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * $Id: clog.h,v 1.1 2001/08/25 18:52:42 tgl Exp $
+ */
+#ifndef CLOG_H
+#define CLOG_H
+
+#include "access/xlog.h"
+
+/*
+ * Possible transaction statuses --- note that all-zeroes is the initial
+ * state.
+ */
+typedef int XidStatus;
+
+#define TRANSACTION_STATUS_IN_PROGRESS		0x00
+#define TRANSACTION_STATUS_COMMITTED		0x01
+#define TRANSACTION_STATUS_ABORTED			0x02
+/* 0x03 is available without changing commit log space allocation */
+
+
+extern void TransactionIdSetStatus(TransactionId xid, XidStatus status);
+extern XidStatus TransactionIdGetStatus(TransactionId xid);
+
+extern int	CLOGShmemSize(void);
+extern void CLOGShmemInit(void);
+extern void BootStrapCLOG(void);
+extern void StartupCLOG(void);
+extern void ShutdownCLOG(void);
+extern void CheckPointCLOG(void);
+extern void ExtendCLOG(TransactionId newestXact);
+extern void TruncateCLOG(TransactionId oldestXact);
+
+/* XLOG stuff */
+#define CLOG_ZEROPAGE		0x00
+
+extern void clog_redo(XLogRecPtr lsn, XLogRecord *record);
+extern void clog_undo(XLogRecPtr lsn, XLogRecord *record);
+extern void clog_desc(char *buf, uint8 xl_info, char *rec);
+
+#endif	 /* CLOG_H */
-- 
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