postgresql/src/include/catalog/pg_control.h

132 lines
4.0 KiB
C

/*-------------------------------------------------------------------------
*
* pg_control.h
* The system control file "pg_control" is not a heap relation.
* However, we define it here so that the format is documented.
*
*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/catalog/pg_control.h,v 1.14 2004/05/21 05:08:04 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef PG_CONTROL_H
#define PG_CONTROL_H
#include "access/xlogdefs.h"
#include "pgtime.h"
#include "utils/pg_crc.h"
/* Version identifier for this pg_control format */
#define PG_CONTROL_VERSION 73
/*
* Body of CheckPoint XLOG records. This is declared here because we keep
* a copy of the latest one in pg_control for possible disaster recovery.
*/
typedef struct CheckPoint
{
XLogRecPtr redo; /* next RecPtr available when we */
/* began to create CheckPoint */
/* (i.e. REDO start point) */
XLogRecPtr undo; /* first record of oldest in-progress */
/* transaction when we started */
/* (i.e. UNDO end point) */
StartUpID ThisStartUpID; /* current SUI */
TransactionId nextXid; /* next free XID */
Oid nextOid; /* next free OID */
time_t time; /* time stamp of checkpoint */
} CheckPoint;
/* XLOG info values for XLOG rmgr */
#define XLOG_CHECKPOINT_SHUTDOWN 0x00
#define XLOG_CHECKPOINT_ONLINE 0x10
#define XLOG_NEXTOID 0x30
#define XLOG_FILE_HEADER 0x40
#define XLOG_WASTED_SPACE 0x50
/* System status indicator */
typedef enum DBState
{
DB_STARTUP = 0,
DB_SHUTDOWNED,
DB_SHUTDOWNING,
DB_IN_RECOVERY,
DB_IN_PRODUCTION
} DBState;
#define LOCALE_NAME_BUFLEN 128
/*
* Contents of pg_control.
*
* NOTE: try to keep this under 512 bytes so that it will fit on one physical
* sector of typical disk drives. This reduces the odds of corruption due to
* power failure midway through a write. Currently it fits comfortably,
* but we could probably reduce LOCALE_NAME_BUFLEN if things get tight.
*/
typedef struct ControlFileData
{
crc64 crc; /* CRC for remainder of struct */
/*
* Version identifier information. Keep these fields at the front,
* especially pg_control_version; they won't be real useful if they
* move around.
*
* pg_control_version identifies the format of pg_control itself.
* catalog_version_no identifies the format of the system catalogs.
*
* There are additional version identifiers in individual files; for
* example, WAL logs contain per-page magic numbers that can serve as
* version cues for the WAL log.
*/
uint32 pg_control_version; /* PG_CONTROL_VERSION */
uint32 catalog_version_no; /* see catversion.h */
/*
* Unique system identifier --- to ensure we match up xlog files with
* the installation that produced them.
*/
uint64 system_identifier;
/*
* System status data
*/
DBState state; /* see enum above */
time_t time; /* time stamp of last pg_control update */
uint32 logId; /* current log file id */
uint32 logSeg; /* current log file segment, + 1 */
XLogRecPtr checkPoint; /* last check point record ptr */
XLogRecPtr prevCheckPoint; /* previous check point record ptr */
CheckPoint checkPointCopy; /* copy of last check point record */
/*
* This data is used to make sure that configuration of this database
* is compatible with the backend executable.
*/
uint32 blcksz; /* block size for this DB */
uint32 relseg_size; /* blocks per segment of large relation */
uint32 xlog_seg_size; /* size of each WAL segment */
uint32 nameDataLen; /* catalog name field width */
uint32 funcMaxArgs; /* maximum number of function arguments */
/* flag indicating internal format of timestamp, interval, time */
uint32 enableIntTimes; /* int64 storage enabled? */
/* active locales */
uint32 localeBuflen;
char lc_collate[LOCALE_NAME_BUFLEN];
char lc_ctype[LOCALE_NAME_BUFLEN];
} ControlFileData;
#endif /* PG_CONTROL_H */