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db_include/replication/syncrep.h

@@ -0,0 +1,115 @@
+/*-------------------------------------------------------------------------
+ *
+ * syncrep.h
+ *	  Exports from replication/syncrep.c.
+ *
+ * Portions Copyright (c) 2010-2021, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		src/include/replication/syncrep.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _SYNCREP_H
+#define _SYNCREP_H
+
+#include "access/xlogdefs.h"
+#include "utils/guc.h"
+
+#define SyncRepRequested() \
+	(max_wal_senders > 0 && synchronous_commit > SYNCHRONOUS_COMMIT_LOCAL_FLUSH)
+
+/* SyncRepWaitMode */
+#define SYNC_REP_NO_WAIT		(-1)
+#define SYNC_REP_WAIT_WRITE		0
+#define SYNC_REP_WAIT_FLUSH		1
+#define SYNC_REP_WAIT_APPLY		2
+
+#define NUM_SYNC_REP_WAIT_MODE	3
+
+/* syncRepState */
+#define SYNC_REP_NOT_WAITING		0
+#define SYNC_REP_WAITING			1
+#define SYNC_REP_WAIT_COMPLETE		2
+
+/* syncrep_method of SyncRepConfigData */
+#define SYNC_REP_PRIORITY		0
+#define SYNC_REP_QUORUM		1
+
+/*
+ * SyncRepGetCandidateStandbys returns an array of these structs,
+ * one per candidate synchronous walsender.
+ */
+typedef struct SyncRepStandbyData
+{
+	/* Copies of relevant fields from WalSnd shared-memory struct */
+	pid_t		pid;
+	XLogRecPtr	write;
+	XLogRecPtr	flush;
+	XLogRecPtr	apply;
+	int			sync_standby_priority;
+	/* Index of this walsender in the WalSnd shared-memory array */
+	int			walsnd_index;
+	/* This flag indicates whether this struct is about our own process */
+	bool		is_me;
+} SyncRepStandbyData;
+
+/*
+ * Struct for the configuration of synchronous replication.
+ *
+ * Note: this must be a flat representation that can be held in a single
+ * chunk of malloc'd memory, so that it can be stored as the "extra" data
+ * for the synchronous_standby_names GUC.
+ */
+typedef struct SyncRepConfigData
+{
+	int			config_size;	/* total size of this struct, in bytes */
+	int			num_sync;		/* number of sync standbys that we need to
+								 * wait for */
+	uint8		syncrep_method; /* method to choose sync standbys */
+	int			nmembers;		/* number of members in the following list */
+	/* member_names contains nmembers consecutive nul-terminated C strings */
+	char		member_names[FLEXIBLE_ARRAY_MEMBER];
+} SyncRepConfigData;
+
+extern SyncRepConfigData *SyncRepConfig;
+
+/* communication variables for parsing synchronous_standby_names GUC */
+extern SyncRepConfigData *syncrep_parse_result;
+extern char *syncrep_parse_error_msg;
+
+/* user-settable parameters for synchronous replication */
+extern char *SyncRepStandbyNames;
+
+/* called by user backend */
+extern void SyncRepWaitForLSN(XLogRecPtr lsn, bool commit);
+
+/* called at backend exit */
+extern void SyncRepCleanupAtProcExit(void);
+
+/* called by wal sender */
+extern void SyncRepInitConfig(void);
+extern void SyncRepReleaseWaiters(void);
+
+/* called by wal sender and user backend */
+extern int	SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys);
+
+/* called by checkpointer */
+extern void SyncRepUpdateSyncStandbysDefined(void);
+
+/* GUC infrastructure */
+extern bool check_synchronous_standby_names(char **newval, void **extra, GucSource source);
+extern void assign_synchronous_standby_names(const char *newval, void *extra);
+extern void assign_synchronous_commit(int newval, void *extra);
+
+/*
+ * Internal functions for parsing synchronous_standby_names grammar,
+ * in syncrep_gram.y and syncrep_scanner.l
+ */
+extern int	syncrep_yyparse(void);
+extern int	syncrep_yylex(void);
+extern void syncrep_yyerror(const char *str);
+extern void syncrep_scanner_init(const char *query_string);
+extern void syncrep_scanner_finish(void);
+
+#endif							/* _SYNCREP_H */