1 /*------------------------------------------------------------------------- 2 * 3 * syncrep.h 4 * Exports from replication/syncrep.c. 5 * 6 * Portions Copyright (c) 2010-2018, PostgreSQL Global Development Group 7 * 8 * IDENTIFICATION 9 * src/include/replication/syncrep.h 10 * 11 *------------------------------------------------------------------------- 12 */ 13 #ifndef _SYNCREP_H 14 #define _SYNCREP_H 15 16 #include "access/xlogdefs.h" 17 #include "utils/guc.h" 18 19 #define SyncRepRequested() \ 20 (max_wal_senders > 0 && synchronous_commit > SYNCHRONOUS_COMMIT_LOCAL_FLUSH) 21 22 /* SyncRepWaitMode */ 23 #define SYNC_REP_NO_WAIT (-1) 24 #define SYNC_REP_WAIT_WRITE 0 25 #define SYNC_REP_WAIT_FLUSH 1 26 #define SYNC_REP_WAIT_APPLY 2 27 28 #define NUM_SYNC_REP_WAIT_MODE 3 29 30 /* syncRepState */ 31 #define SYNC_REP_NOT_WAITING 0 32 #define SYNC_REP_WAITING 1 33 #define SYNC_REP_WAIT_COMPLETE 2 34 35 /* syncrep_method of SyncRepConfigData */ 36 #define SYNC_REP_PRIORITY 0 37 #define SYNC_REP_QUORUM 1 38 39 /* 40 * SyncRepGetCandidateStandbys returns an array of these structs, 41 * one per candidate synchronous walsender. 42 */ 43 typedef struct SyncRepStandbyData 44 { 45 /* Copies of relevant fields from WalSnd shared-memory struct */ 46 pid_t pid; 47 XLogRecPtr write; 48 XLogRecPtr flush; 49 XLogRecPtr apply; 50 int sync_standby_priority; 51 /* Index of this walsender in the WalSnd shared-memory array */ 52 int walsnd_index; 53 /* This flag indicates whether this struct is about our own process */ 54 bool is_me; 55 } SyncRepStandbyData; 56 57 /* 58 * Struct for the configuration of synchronous replication. 59 * 60 * Note: this must be a flat representation that can be held in a single 61 * chunk of malloc'd memory, so that it can be stored as the "extra" data 62 * for the synchronous_standby_names GUC. 63 */ 64 typedef struct SyncRepConfigData 65 { 66 int config_size; /* total size of this struct, in bytes */ 67 int num_sync; /* number of sync standbys that we need to 68 * wait for */ 69 uint8 syncrep_method; /* method to choose sync standbys */ 70 int nmembers; /* number of members in the following list */ 71 /* member_names contains nmembers consecutive nul-terminated C strings */ 72 char member_names[FLEXIBLE_ARRAY_MEMBER]; 73 } SyncRepConfigData; 74 75 extern SyncRepConfigData *SyncRepConfig; 76 77 /* communication variables for parsing synchronous_standby_names GUC */ 78 extern SyncRepConfigData *syncrep_parse_result; 79 extern char *syncrep_parse_error_msg; 80 81 /* user-settable parameters for synchronous replication */ 82 extern char *SyncRepStandbyNames; 83 84 /* called by user backend */ 85 extern void SyncRepWaitForLSN(XLogRecPtr lsn, bool commit); 86 87 /* called at backend exit */ 88 extern void SyncRepCleanupAtProcExit(void); 89 90 /* called by wal sender */ 91 extern void SyncRepInitConfig(void); 92 extern void SyncRepReleaseWaiters(void); 93 94 /* called by wal sender and user backend */ 95 extern int SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys); 96 97 /* obsolete, do not use in new code */ 98 extern List *SyncRepGetSyncStandbys(bool *am_sync); 99 100 /* called by checkpointer */ 101 extern void SyncRepUpdateSyncStandbysDefined(void); 102 103 /* GUC infrastructure */ 104 extern bool check_synchronous_standby_names(char **newval, void **extra, GucSource source); 105 extern void assign_synchronous_standby_names(const char *newval, void *extra); 106 extern void assign_synchronous_commit(int newval, void *extra); 107 108 /* 109 * Internal functions for parsing synchronous_standby_names grammar, 110 * in syncrep_gram.y and syncrep_scanner.l 111 */ 112 extern int syncrep_yyparse(void); 113 extern int syncrep_yylex(void); 114 extern void syncrep_yyerror(const char *str); 115 extern void syncrep_scanner_init(const char *query_string); 116 extern void syncrep_scanner_finish(void); 117 118 #endif /* _SYNCREP_H */ 119