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/*-------------------------------------------------------------------------
*
* walreceiver.h
* Exports from replication/walreceiverfuncs.c.
*
* Portions Copyright (c) 2010-2012, PostgreSQL Global Development Group
*
* src/include/replication/walreceiver.h
*
*-------------------------------------------------------------------------
*/
#ifndef _WALRECEIVER_H
#define _WALRECEIVER_H
#include "access/xlog.h"
#include "access/xlogdefs.h"
#include "storage/latch.h"
#include "storage/spin.h"
#include "pgtime.h"
/* user-settable parameters */
extern int wal_receiver_status_interval;
extern int wal_receiver_timeout;
extern bool hot_standby_feedback;
/*
* MAXCONNINFO: maximum size of a connection string.
*
* XXX: Should this move to pg_config_manual.h?
*/
#define MAXCONNINFO 1024
/* Can we allow the standby to accept replication connection from another standby? */
#define AllowCascadeReplication() (EnableHotStandby && max_wal_senders > 0)
/*
* Values for WalRcv->walRcvState.
*/
typedef enum
{
WALRCV_STOPPED, /* stopped and mustn't start up again */
WALRCV_STARTING, /* launched, but the process hasn't
* initialized yet */
WALRCV_STREAMING, /* walreceiver is streaming */
WALRCV_WAITING, /* stopped streaming, waiting for orders */
WALRCV_RESTARTING, /* asked to restart streaming */
WALRCV_STOPPING /* requested to stop, but still running */
} WalRcvState;
/* Shared memory area for management of walreceiver process */
typedef struct
{
/*
* PID of currently active walreceiver process, its current state and
* start time (actually, the time at which it was requested to be
* started).
*/
pid_t pid;
WalRcvState walRcvState;
pg_time_t startTime;
/*
* receiveStart and receiveStartTLI indicate the first byte position
* and timeline that will be received. When startup process starts the
* walreceiver, it sets these to the point where it wants the streaming
* to begin.
*/
XLogRecPtr receiveStart;
TimeLineID receiveStartTLI;
/*
* receivedUpto-1 is the last byte position that has already been
* received, and receivedTLI is the timeline it came from. At the first
* startup of walreceiver, these are set to receiveStart and
* receiveStartTLI. After that, walreceiver updates these whenever it
* flushes the received WAL to disk.
*/
XLogRecPtr receivedUpto;
TimeLineID receivedTLI;
/*
* latestChunkStart is the starting byte position of the current "batch"
* of received WAL. It's actually the same as the previous value of
* receivedUpto before the last flush to disk. Startup process can use
* this to detect whether it's keeping up or not.
*/
XLogRecPtr latestChunkStart;
/*
* Time of send and receive of any message received.
*/
TimestampTz lastMsgSendTime;
TimestampTz lastMsgReceiptTime;
/*
* Latest reported end of WAL on the sender
*/
XLogRecPtr latestWalEnd;
TimestampTz latestWalEndTime;
/*
* connection string; is used for walreceiver to connect with the primary.
*/
char conninfo[MAXCONNINFO];
slock_t mutex; /* locks shared variables shown above */
/*
* Latch used by startup process to wake up walreceiver after telling it
* where to start streaming (after setting receiveStart and
* receiveStartTLI).
*/
Latch latch;
} WalRcvData;
extern WalRcvData *WalRcv;
/* libpqwalreceiver hooks */
typedef void (*walrcv_connect_type) (char *conninfo);
extern PGDLLIMPORT walrcv_connect_type walrcv_connect;
typedef void (*walrcv_identify_system_type) (TimeLineID *primary_tli);
extern PGDLLIMPORT walrcv_identify_system_type walrcv_identify_system;
typedef void (*walrcv_readtimelinehistoryfile_type) (TimeLineID tli, char **filename, char **content, int *size);
extern PGDLLIMPORT walrcv_readtimelinehistoryfile_type walrcv_readtimelinehistoryfile;
typedef bool (*walrcv_startstreaming_type) (TimeLineID tli, XLogRecPtr startpoint);
extern PGDLLIMPORT walrcv_startstreaming_type walrcv_startstreaming;
typedef void (*walrcv_endstreaming_type) (void);
extern PGDLLIMPORT walrcv_endstreaming_type walrcv_endstreaming;
typedef int (*walrcv_receive_type) (int timeout, char **buffer);
extern PGDLLIMPORT walrcv_receive_type walrcv_receive;
typedef void (*walrcv_send_type) (const char *buffer, int nbytes);
extern PGDLLIMPORT walrcv_send_type walrcv_send;
typedef void (*walrcv_disconnect_type) (void);
extern PGDLLIMPORT walrcv_disconnect_type walrcv_disconnect;
/* prototypes for functions in walreceiver.c */
extern void WalReceiverMain(void) __attribute__((noreturn));
/* prototypes for functions in walreceiverfuncs.c */
extern Size WalRcvShmemSize(void);
extern void WalRcvShmemInit(void);
extern void ShutdownWalRcv(void);
extern bool WalRcvStreaming(void);
extern bool WalRcvRunning(void);
extern void RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo);
extern XLogRecPtr GetWalRcvWriteRecPtr(XLogRecPtr *latestChunkStart, TimeLineID *receiveTLI);
extern int GetReplicationApplyDelay(void);
extern int GetReplicationTransferLatency(void);
#endif /* _WALRECEIVER_H */
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