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db_include/replication/walsender_private.h

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+/*-------------------------------------------------------------------------
+ *
+ * walsender_private.h
+ *	  Private definitions from replication/walsender.c.
+ *
+ * Portions Copyright (c) 2010-2021, PostgreSQL Global Development Group
+ *
+ * src/include/replication/walsender_private.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _WALSENDER_PRIVATE_H
+#define _WALSENDER_PRIVATE_H
+
+#include "access/xlog.h"
+#include "nodes/nodes.h"
+#include "replication/syncrep.h"
+#include "storage/latch.h"
+#include "storage/shmem.h"
+#include "storage/spin.h"
+
+typedef enum WalSndState
+{
+	WALSNDSTATE_STARTUP = 0,
+	WALSNDSTATE_BACKUP,
+	WALSNDSTATE_CATCHUP,
+	WALSNDSTATE_STREAMING,
+	WALSNDSTATE_STOPPING
+} WalSndState;
+
+/*
+ * Each walsender has a WalSnd struct in shared memory.
+ *
+ * This struct is protected by its 'mutex' spinlock field, except that some
+ * members are only written by the walsender process itself, and thus that
+ * process is free to read those members without holding spinlock.  pid and
+ * needreload always require the spinlock to be held for all accesses.
+ */
+typedef struct WalSnd
+{
+	pid_t		pid;			/* this walsender's PID, or 0 if not active */
+
+	WalSndState state;			/* this walsender's state */
+	XLogRecPtr	sentPtr;		/* WAL has been sent up to this point */
+	bool		needreload;		/* does currently-open file need to be
+								 * reloaded? */
+
+	/*
+	 * The xlog locations that have been written, flushed, and applied by
+	 * standby-side. These may be invalid if the standby-side has not offered
+	 * values yet.
+	 */
+	XLogRecPtr	write;
+	XLogRecPtr	flush;
+	XLogRecPtr	apply;
+
+	/* Measured lag times, or -1 for unknown/none. */
+	TimeOffset	writeLag;
+	TimeOffset	flushLag;
+	TimeOffset	applyLag;
+
+	/*
+	 * The priority order of the standby managed by this WALSender, as listed
+	 * in synchronous_standby_names, or 0 if not-listed.
+	 */
+	int			sync_standby_priority;
+
+	/* Protects shared variables shown above. */
+	slock_t		mutex;
+
+	/*
+	 * Pointer to the walsender's latch. Used by backends to wake up this
+	 * walsender when it has work to do. NULL if the walsender isn't active.
+	 */
+	Latch	   *latch;
+
+	/*
+	 * Timestamp of the last message received from standby.
+	 */
+	TimestampTz replyTime;
+} WalSnd;
+
+extern WalSnd *MyWalSnd;
+
+/* There is one WalSndCtl struct for the whole database cluster */
+typedef struct
+{
+	/*
+	 * Synchronous replication queue with one queue per request type.
+	 * Protected by SyncRepLock.
+	 */
+	SHM_QUEUE	SyncRepQueue[NUM_SYNC_REP_WAIT_MODE];
+
+	/*
+	 * Current location of the head of the queue. All waiters should have a
+	 * waitLSN that follows this value. Protected by SyncRepLock.
+	 */
+	XLogRecPtr	lsn[NUM_SYNC_REP_WAIT_MODE];
+
+	/*
+	 * Are any sync standbys defined?  Waiting backends can't reload the
+	 * config file safely, so checkpointer updates this value as needed.
+	 * Protected by SyncRepLock.
+	 */
+	bool		sync_standbys_defined;
+
+	WalSnd		walsnds[FLEXIBLE_ARRAY_MEMBER];
+} WalSndCtlData;
+
+extern WalSndCtlData *WalSndCtl;
+
+
+extern void WalSndSetState(WalSndState state);
+
+/*
+ * Internal functions for parsing the replication grammar, in repl_gram.y and
+ * repl_scanner.l
+ */
+extern int	replication_yyparse(void);
+extern int	replication_yylex(void);
+extern void replication_yyerror(const char *str) pg_attribute_noreturn();
+extern void replication_scanner_init(const char *query_string);
+extern void replication_scanner_finish(void);
+extern bool replication_scanner_is_replication_command(void);
+
+extern Node *replication_parse_result;
+
+#endif							/* _WALSENDER_PRIVATE_H */