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syncrep.h
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1 /*-------------------------------------------------------------------------
2  *
3  * syncrep.h
4  * Exports from replication/syncrep.c.
5  *
6  * Portions Copyright (c) 2010-2020, 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;
51  /* Index of this walsender in the WalSnd shared-memory array */
53  /* This flag indicates whether this struct is about our own process */
54  bool is_me;
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];
74 
76 
77 /* communication variables for parsing synchronous_standby_names GUC */
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 /* called by checkpointer */
98 extern void SyncRepUpdateSyncStandbysDefined(void);
99 
100 /* GUC infrastructure */
101 extern bool check_synchronous_standby_names(char **newval, void **extra, GucSource source);
102 extern void assign_synchronous_standby_names(const char *newval, void *extra);
103 extern void assign_synchronous_commit(int newval, void *extra);
104 
105 /*
106  * Internal functions for parsing synchronous_standby_names grammar,
107  * in syncrep_gram.y and syncrep_scanner.l
108  */
109 extern int syncrep_yyparse(void);
110 extern int syncrep_yylex(void);
111 extern void syncrep_yyerror(const char *str);
112 extern void syncrep_scanner_init(const char *query_string);
113 extern void syncrep_scanner_finish(void);
114 
115 #endif /* _SYNCREP_H */
void syncrep_scanner_finish(void)
void SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
Definition: syncrep.c:148
void syncrep_scanner_init(const char *query_string)
int syncrep_yylex(void)
char * syncrep_parse_error_msg
void assign_synchronous_standby_names(const char *newval, void *extra)
Definition: syncrep.c:1069
uint8 syncrep_method
Definition: syncrep.h:69
unsigned char uint8
Definition: c.h:365
#define FLEXIBLE_ARRAY_MEMBER
Definition: c.h:276
void SyncRepReleaseWaiters(void)
Definition: syncrep.c:429
int sync_standby_priority
Definition: syncrep.h:50
char * SyncRepStandbyNames
Definition: syncrep.c:90
GucSource
Definition: guc.h:105
XLogRecPtr flush
Definition: syncrep.h:48
SyncRepConfigData * SyncRepConfig
Definition: syncrep.c:97
void syncrep_yyerror(const char *str)
XLogRecPtr write
Definition: syncrep.h:47
XLogRecPtr apply
Definition: syncrep.h:49
void SyncRepInitConfig(void)
Definition: syncrep.c:400
struct SyncRepConfigData SyncRepConfigData
uint64 XLogRecPtr
Definition: xlogdefs.h:21
void SyncRepCleanupAtProcExit(void)
Definition: syncrep.c:371
SyncRepConfigData * syncrep_parse_result
#define newval
struct SyncRepStandbyData SyncRepStandbyData
void assign_synchronous_commit(int newval, void *extra)
Definition: syncrep.c:1075
bool check_synchronous_standby_names(char **newval, void **extra, GucSource source)
Definition: syncrep.c:1012
int SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
Definition: syncrep.c:714
void SyncRepUpdateSyncStandbysDefined(void)
Definition: syncrep.c:936
int syncrep_yyparse(void)