*** pgsql/src/include/access/xlog.h	2009/06/26 20:29:04	1.93
--- pgsql/src/include/access/xlog.h	2009/12/19 01:32:42	1.94
***************
*** 6,12 ****
   * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
!  * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.92 2009/06/25 21:36:00 heikki Exp $
   */
  #ifndef XLOG_H
  #define XLOG_H
--- 6,12 ----
   * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
!  * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.93 2009/06/26 20:29:04 tgl Exp $
   */
  #ifndef XLOG_H
  #define XLOG_H
*************** typedef struct XLogRecData
*** 133,139 ****
--- 133,177 ----
  } XLogRecData;
  
  extern TimeLineID ThisTimeLineID;		/* current TLI */
+ 
+ /*
+  * Prior to 8.4, all activity during recovery was carried out by Startup
+  * process. This local variable continues to be used in many parts of the
+  * code to indicate actions taken by RecoveryManagers. Other processes who
+  * potentially perform work during recovery should check RecoveryInProgress()
+  * see XLogCtl notes in xlog.c
+  */
  extern bool InRecovery;
+ 
+ /*
+  * Like InRecovery, standbyState is only valid in the startup process.
+  *
+  * In DISABLED state, we're performing crash recovery or hot standby was
+  * disabled in recovery.conf.
+  *
+  * In INITIALIZED state, we haven't yet received a RUNNING_XACTS or shutdown
+  * checkpoint record to initialize our master transaction tracking system.
+  *
+  * When the transaction tracking is initialized, we enter the SNAPSHOT_PENDING
+  * state. The tracked information might still be incomplete, so we can't allow
+  * connections yet, but redo functions must update the in-memory state when
+  * appropriate.
+  *
+  * In SNAPSHOT_READY mode, we have full knowledge of transactions that are
+  * (or were) running in the master at the current WAL location. Snapshots
+  * can be taken, and read-only queries can be run.
+  */
+ typedef enum
+ {
+ 	STANDBY_DISABLED,
+ 	STANDBY_INITIALIZED,
+ 	STANDBY_SNAPSHOT_PENDING,
+ 	STANDBY_SNAPSHOT_READY
+ } HotStandbyState;
+ extern HotStandbyState standbyState;
+ 
+ #define InHotStandby (standbyState >= STANDBY_SNAPSHOT_PENDING)
+ 
  extern XLogRecPtr XactLastRecEnd;
  
  /* these variables are GUC parameters related to XLOG */
*************** extern bool XLogArchiveMode;
*** 143,151 ****
--- 181,192 ----
  extern char *XLogArchiveCommand;
  extern int	XLogArchiveTimeout;
  extern bool log_checkpoints;
+ extern bool XLogRequestRecoveryConnections;
+ extern int MaxStandbyDelay;
  
  #define XLogArchivingActive()	(XLogArchiveMode)
  #define XLogArchiveCommandSet() (XLogArchiveCommand[0] != '\0')
+ #define XLogStandbyInfoActive()	(XLogRequestRecoveryConnections && XLogArchiveMode)
  
  #ifdef WAL_DEBUG
  extern bool XLOG_DEBUG;
*************** extern void xlog_desc(StringInfo buf, ui
*** 203,208 ****
--- 244,250 ----
  
  extern bool RecoveryInProgress(void);
  extern bool XLogInsertAllowed(void);
+ extern TimestampTz GetLatestXLogTime(void);
  
  extern void UpdateControlFile(void);
  extern Size XLOGShmemSize(void);