Introduce Streaming Replication.

This includes two new kinds of postmaster processes, walsenders and
walreceiver. Walreceiver is responsible for connecting to the primary server
and streaming WAL to disk, while walsender runs in the primary server and
streams WAL from disk to the client.

Documentation still needs work, but the basics are there. We will probably
pull the replication section to a new chapter later on, as well as the
sections describing file-based replication. But let's do that as a separate
patch, so that it's easier to see what has been added/changed. This patch
also adds a new section to the chapter about FE/BE protocol, documenting the
protocol used by walsender/walreceivxer.

Bump catalog version because of two new functions,
pg_last_xlog_receive_location() and pg_last_xlog_replay_location(), for
monitoring the progress of replication.

Fujii Masao, with additional hacking by me

1 files changed, 49 insertions, 0 deletions

diff --git a/src/include/replication/walsender.h b/src/include/replication/walsender.h
new file mode 100644
index 0000000000..c9bfd12e8b
--- /dev/null
+++ b/src/include/replication/walsender.h
@@ -0,0 +1,49 @@
+/*-------------------------------------------------------------------------
+ *
+ * walsender.h
+ *	  Exports from replication/walsender.c.
+ *
+ * Portions Copyright (c) 2010-2010, PostgreSQL Global Development Group
+ *
+ * $PostgreSQL: pgsql/src/include/replication/walsender.h,v 1.1 2010/01/15 09:19:09 heikki Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _WALSENDER_H
+#define _WALSENDER_H
+
+#include "access/xlog.h"
+#include "storage/spin.h"
+
+/*
+ * Each walsender has a WalSnd struct in shared memory.
+ */
+typedef struct WalSnd
+{
+	pid_t	pid;		/* this walsender's process id, or 0 */
+	XLogRecPtr sentPtr;	/* WAL has been sent up to this point */
+
+	slock_t	mutex;		/* locks shared variables shown above */
+} WalSnd;
+
+/* There is one WalSndCtl struct for the whole database cluster */
+typedef struct
+{
+	WalSnd	walsnds[1];		/* VARIABLE LENGTH ARRAY */
+} WalSndCtlData;
+
+extern WalSndCtlData *WalSndCtl;
+
+/* global state */
+extern bool	am_walsender;
+
+/* user-settable parameters */
+extern int	WalSndDelay;
+
+extern int WalSenderMain(void);
+extern void WalSndSignals(void);
+extern Size WalSndShmemSize(void);
+extern void WalSndShmemInit(void);
+extern XLogRecPtr GetOldestWALSendPointer(void);
+
+#endif	/* _WALSENDER_H */