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xlog.h
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1 /*
2  * xlog.h
3  *
4  * PostgreSQL write-ahead log manager
5  *
6  * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
7  * Portions Copyright (c) 1994, Regents of the University of California
8  *
9  * src/include/access/xlog.h
10  */
11 #ifndef XLOG_H
12 #define XLOG_H
13 
14 #include "access/rmgr.h"
15 #include "access/xlogdefs.h"
16 #include "access/xloginsert.h"
17 #include "access/xlogreader.h"
18 #include "datatype/timestamp.h"
19 #include "lib/stringinfo.h"
20 #include "nodes/pg_list.h"
21 #include "storage/fd.h"
22 
23 
24 /* Sync methods */
25 #define SYNC_METHOD_FSYNC 0
26 #define SYNC_METHOD_FDATASYNC 1
27 #define SYNC_METHOD_OPEN 2 /* for O_SYNC */
28 #define SYNC_METHOD_FSYNC_WRITETHROUGH 3
29 #define SYNC_METHOD_OPEN_DSYNC 4 /* for O_DSYNC */
30 extern int sync_method;
31 
32 extern PGDLLIMPORT TimeLineID ThisTimeLineID; /* current TLI */
33 
34 /*
35  * Prior to 8.4, all activity during recovery was carried out by the startup
36  * process. This local variable continues to be used in many parts of the
37  * code to indicate actions taken by RecoveryManagers. Other processes that
38  * potentially perform work during recovery should check RecoveryInProgress().
39  * See XLogCtl notes in xlog.c.
40  */
41 extern bool InRecovery;
42 
43 /*
44  * Like InRecovery, standbyState is only valid in the startup process.
45  * In all other processes it will have the value STANDBY_DISABLED (so
46  * InHotStandby will read as false).
47  *
48  * In DISABLED state, we're performing crash recovery or hot standby was
49  * disabled in postgresql.conf.
50  *
51  * In INITIALIZED state, we've run InitRecoveryTransactionEnvironment, but
52  * we haven't yet processed a RUNNING_XACTS or shutdown-checkpoint WAL record
53  * to initialize our master-transaction tracking system.
54  *
55  * When the transaction tracking is initialized, we enter the SNAPSHOT_PENDING
56  * state. The tracked information might still be incomplete, so we can't allow
57  * connections yet, but redo functions must update the in-memory state when
58  * appropriate.
59  *
60  * In SNAPSHOT_READY mode, we have full knowledge of transactions that are
61  * (or were) running in the master at the current WAL location. Snapshots
62  * can be taken, and read-only queries can be run.
63  */
64 typedef enum
65 {
71 
73 
74 #define InHotStandby (standbyState >= STANDBY_SNAPSHOT_PENDING)
75 
76 /*
77  * Recovery target type.
78  * Only set during a Point in Time recovery, not when standby_mode = on
79  */
80 typedef enum
81 {
89 
93 
94 extern bool reachedConsistency;
95 
96 /* these variables are GUC parameters related to XLOG */
97 extern int wal_segment_size;
98 extern int min_wal_size_mb;
99 extern int max_wal_size_mb;
100 extern int wal_keep_segments;
101 extern int XLOGbuffers;
102 extern int XLogArchiveTimeout;
103 extern int wal_retrieve_retry_interval;
104 extern char *XLogArchiveCommand;
105 extern bool EnableHotStandby;
106 extern bool fullPageWrites;
107 extern bool wal_log_hints;
108 extern bool wal_compression;
109 extern bool *wal_consistency_checking;
111 extern bool log_checkpoints;
112 
113 extern int CheckPointSegments;
114 
115 /* Archive modes */
116 typedef enum ArchiveMode
117 {
118  ARCHIVE_MODE_OFF = 0, /* disabled */
119  ARCHIVE_MODE_ON, /* enabled while server is running normally */
120  ARCHIVE_MODE_ALWAYS /* enabled always (even during recovery) */
121 } ArchiveMode;
122 extern int XLogArchiveMode;
123 
124 /* WAL levels */
125 typedef enum WalLevel
126 {
130 } WalLevel;
131 
132 extern PGDLLIMPORT int wal_level;
133 
134 /* Is WAL archiving enabled (always or only while server is running normally)? */
135 #define XLogArchivingActive() \
136  (AssertMacro(XLogArchiveMode == ARCHIVE_MODE_OFF || wal_level >= WAL_LEVEL_REPLICA), XLogArchiveMode > ARCHIVE_MODE_OFF)
137 /* Is WAL archiving enabled always (even during recovery)? */
138 #define XLogArchivingAlways() \
139  (AssertMacro(XLogArchiveMode == ARCHIVE_MODE_OFF || wal_level >= WAL_LEVEL_REPLICA), XLogArchiveMode == ARCHIVE_MODE_ALWAYS)
140 #define XLogArchiveCommandSet() (XLogArchiveCommand[0] != '\0')
141 
142 /*
143  * Is WAL-logging necessary for archival or log-shipping, or can we skip
144  * WAL-logging if we fsync() the data before committing instead?
145  */
146 #define XLogIsNeeded() (wal_level >= WAL_LEVEL_REPLICA)
147 
148 /*
149  * Is a full-page image needed for hint bit updates?
150  *
151  * Normally, we don't WAL-log hint bit updates, but if checksums are enabled,
152  * we have to protect them against torn page writes. When you only set
153  * individual bits on a page, it's still consistent no matter what combination
154  * of the bits make it to disk, but the checksum wouldn't match. Also WAL-log
155  * them if forced by wal_log_hints=on.
156  */
157 #define XLogHintBitIsNeeded() (DataChecksumsEnabled() || wal_log_hints)
158 
159 /* Do we need to WAL-log information required only for Hot Standby and logical replication? */
160 #define XLogStandbyInfoActive() (wal_level >= WAL_LEVEL_REPLICA)
161 
162 /* Do we need to WAL-log information required only for logical replication? */
163 #define XLogLogicalInfoActive() (wal_level >= WAL_LEVEL_LOGICAL)
164 
165 #ifdef WAL_DEBUG
166 extern bool XLOG_DEBUG;
167 #endif
168 
169 /*
170  * OR-able request flag bits for checkpoints. The "cause" bits are used only
171  * for logging purposes. Note: the flags must be defined so that it's
172  * sensible to OR together request flags arising from different requestors.
173  */
174 
175 /* These directly affect the behavior of CreateCheckPoint and subsidiaries */
176 #define CHECKPOINT_IS_SHUTDOWN 0x0001 /* Checkpoint is for shutdown */
177 #define CHECKPOINT_END_OF_RECOVERY 0x0002 /* Like shutdown checkpoint, but
178  * issued at end of WAL recovery */
179 #define CHECKPOINT_IMMEDIATE 0x0004 /* Do it without delays */
180 #define CHECKPOINT_FORCE 0x0008 /* Force even if no activity */
181 #define CHECKPOINT_FLUSH_ALL 0x0010 /* Flush all pages, including those
182  * belonging to unlogged tables */
183 /* These are important to RequestCheckpoint */
184 #define CHECKPOINT_WAIT 0x0020 /* Wait for completion */
185 /* These indicate the cause of a checkpoint request */
186 #define CHECKPOINT_CAUSE_XLOG 0x0040 /* XLOG consumption */
187 #define CHECKPOINT_CAUSE_TIME 0x0080 /* Elapsed time */
188 
189 /*
190  * Flag bits for the record being inserted, set using XLogSetRecordFlags().
191  */
192 #define XLOG_INCLUDE_ORIGIN 0x01 /* include the replication origin */
193 #define XLOG_MARK_UNIMPORTANT 0x02 /* record not important for durability */
194 
195 
196 /* Checkpoint statistics */
197 typedef struct CheckpointStatsData
198 {
199  TimestampTz ckpt_start_t; /* start of checkpoint */
200  TimestampTz ckpt_write_t; /* start of flushing buffers */
201  TimestampTz ckpt_sync_t; /* start of fsyncs */
202  TimestampTz ckpt_sync_end_t; /* end of fsyncs */
203  TimestampTz ckpt_end_t; /* end of checkpoint */
204 
205  int ckpt_bufs_written; /* # of buffers written */
206 
207  int ckpt_segs_added; /* # of new xlog segments created */
208  int ckpt_segs_removed; /* # of xlog segments deleted */
209  int ckpt_segs_recycled; /* # of xlog segments recycled */
210 
211  int ckpt_sync_rels; /* # of relations synced */
212  uint64 ckpt_longest_sync; /* Longest sync for one relation */
213  uint64 ckpt_agg_sync_time; /* The sum of all the individual sync
214  * times, which is not necessarily the
215  * same as the total elapsed time for the
216  * entire sync phase. */
218 
220 
221 struct XLogRecData;
222 
223 extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
224  XLogRecPtr fpw_lsn,
225  uint8 flags);
226 extern void XLogFlush(XLogRecPtr RecPtr);
227 extern bool XLogBackgroundFlush(void);
228 extern bool XLogNeedsFlush(XLogRecPtr RecPtr);
229 extern int XLogFileInit(XLogSegNo segno, bool *use_existent, bool use_lock);
230 extern int XLogFileOpen(XLogSegNo segno);
231 
232 extern void CheckXLogRemoved(XLogSegNo segno, TimeLineID tli);
234 extern void XLogSetAsyncXactLSN(XLogRecPtr record);
236 
237 extern void xlog_redo(XLogReaderState *record);
238 extern void xlog_desc(StringInfo buf, XLogReaderState *record);
239 extern const char *xlog_identify(uint8 info);
240 
241 extern void issue_xlog_fsync(int fd, XLogSegNo segno);
242 
243 extern bool RecoveryInProgress(void);
244 extern bool HotStandbyActive(void);
245 extern bool HotStandbyActiveInReplay(void);
246 extern bool XLogInsertAllowed(void);
247 extern void GetXLogReceiptTime(TimestampTz *rtime, bool *fromStream);
248 extern XLogRecPtr GetXLogReplayRecPtr(TimeLineID *replayTLI);
249 extern XLogRecPtr GetXLogInsertRecPtr(void);
250 extern XLogRecPtr GetXLogWriteRecPtr(void);
251 extern bool RecoveryIsPaused(void);
252 extern void SetRecoveryPause(bool recoveryPause);
253 extern TimestampTz GetLatestXTime(void);
255 extern char *XLogFileNameP(TimeLineID tli, XLogSegNo segno);
256 
257 extern void UpdateControlFile(void);
258 extern uint64 GetSystemIdentifier(void);
259 extern char *GetMockAuthenticationNonce(void);
260 extern bool DataChecksumsEnabled(void);
262 extern Size XLOGShmemSize(void);
263 extern void XLOGShmemInit(void);
264 extern void BootStrapXLOG(void);
265 extern void LocalProcessControlFile(bool reset);
266 extern void StartupXLOG(void);
267 extern void ShutdownXLOG(int code, Datum arg);
268 extern void InitXLOGAccess(void);
269 extern void CreateCheckPoint(int flags);
270 extern bool CreateRestartPoint(int flags);
271 extern void XLogPutNextOid(Oid nextOid);
272 extern XLogRecPtr XLogRestorePoint(const char *rpName);
273 extern void UpdateFullPageWrites(void);
274 extern void GetFullPageWriteInfo(XLogRecPtr *RedoRecPtr_p, bool *doPageWrites_p);
275 extern XLogRecPtr GetRedoRecPtr(void);
276 extern XLogRecPtr GetInsertRecPtr(void);
277 extern XLogRecPtr GetFlushRecPtr(void);
279 extern void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch);
280 extern void RemovePromoteSignalFiles(void);
281 
282 extern bool CheckPromoteSignal(void);
283 extern void WakeupRecovery(void);
284 extern void SetWalWriterSleeping(bool sleeping);
285 
286 extern void XLogRequestWalReceiverReply(void);
287 
288 extern void assign_max_wal_size(int newval, void *extra);
289 extern void assign_checkpoint_completion_target(double newval, void *extra);
290 
291 /*
292  * Routines to start, stop, and get status of a base backup.
293  */
294 
295 /*
296  * Session-level status of base backups
297  *
298  * This is used in parallel with the shared memory status to control parallel
299  * execution of base backup functions for a given session, be it a backend
300  * dedicated to replication or a normal backend connected to a database. The
301  * update of the session-level status happens at the same time as the shared
302  * memory counters to keep a consistent global and local state of the backups
303  * running.
304  */
305 typedef enum SessionBackupState
306 {
311 
312 extern XLogRecPtr do_pg_start_backup(const char *backupidstr, bool fast,
313  TimeLineID *starttli_p, StringInfo labelfile, DIR *tblspcdir,
314  List **tablespaces, StringInfo tblspcmapfile, bool infotbssize,
315  bool needtblspcmapfile);
316 extern XLogRecPtr do_pg_stop_backup(char *labelfile, bool waitforarchive,
317  TimeLineID *stoptli_p);
318 extern void do_pg_abort_backup(void);
320 
321 /* File path names (all relative to $PGDATA) */
322 #define BACKUP_LABEL_FILE "backup_label"
323 #define BACKUP_LABEL_OLD "backup_label.old"
324 
325 #define TABLESPACE_MAP "tablespace_map"
326 #define TABLESPACE_MAP_OLD "tablespace_map.old"
327 
328 #endif /* XLOG_H */
void CreateCheckPoint(int flags)
Definition: xlog.c:8567
int wal_keep_segments
Definition: xlog.c:91
struct CheckpointStatsData CheckpointStatsData
XLogRecPtr GetXLogWriteRecPtr(void)
Definition: xlog.c:11163
uint64 ckpt_agg_sync_time
Definition: xlog.h:213
TimestampTz ckpt_sync_end_t
Definition: xlog.h:202
bool CreateRestartPoint(int flags)
Definition: xlog.c:9112
int ckpt_sync_rels
Definition: xlog.h:211
bool XLogInsertAllowed(void)
Definition: xlog.c:8024
int min_wal_size_mb
Definition: xlog.c:90
bool XLogNeedsFlush(XLogRecPtr RecPtr)
Definition: xlog.c:3084
uint32 TimeLineID
Definition: xlogdefs.h:45
XLogRecPtr GetRedoRecPtr(void)
Definition: xlog.c:8202
bool DataChecksumsEnabled(void)
Definition: xlog.c:4738
void WakeupRecovery(void)
Definition: xlog.c:12138
uint32 TransactionId
Definition: c.h:445
void XLogFlush(XLogRecPtr RecPtr)
Definition: xlog.c:2763
void xlog_desc(StringInfo buf, XLogReaderState *record)
Definition: xlogdesc.c:36
bool HotStandbyActive(void)
Definition: xlog.c:7985
int64 TimestampTz
Definition: timestamp.h:39
int XLogFileOpen(XLogSegNo segno)
Definition: xlog.c:3525
TimestampTz ckpt_start_t
Definition: xlog.h:199
XLogRecPtr XactLastRecEnd
Definition: xlog.c:339
bool wal_log_hints
Definition: xlog.c:98
void LocalProcessControlFile(bool reset)
Definition: xlog.c:4838
unsigned char uint8
Definition: c.h:294
char * GetMockAuthenticationNonce(void)
Definition: xlog.c:4728
int ckpt_segs_recycled
Definition: xlog.h:209
bool fullPageWrites
Definition: xlog.c:97
XLogSegNo XLogGetLastRemovedSegno(void)
Definition: xlog.c:3797
int max_wal_size_mb
Definition: xlog.c:89
void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch)
Definition: xlog.c:8330
char * wal_consistency_checking_string
Definition: xlog.c:100
unsigned int Oid
Definition: postgres_ext.h:31
void SetRecoveryPause(bool recoveryPause)
Definition: xlog.c:6017
bool CheckPromoteSignal(void)
Definition: xlog.c:12122
XLogRecPtr do_pg_start_backup(const char *backupidstr, bool fast, TimeLineID *starttli_p, StringInfo labelfile, DIR *tblspcdir, List **tablespaces, StringInfo tblspcmapfile, bool infotbssize, bool needtblspcmapfile)
Definition: xlog.c:10213
XLogRecPtr GetXLogReplayRecPtr(TimeLineID *replayTLI)
Definition: xlog.c:11128
static int fd(const char *x, int i)
Definition: preproc-init.c:105
void UpdateFullPageWrites(void)
Definition: xlog.c:9540
bool XLogBackgroundFlush(void)
Definition: xlog.c:2952
#define PGDLLIMPORT
Definition: c.h:1050
void xlog_redo(XLogReaderState *record)
Definition: xlog.c:9644
char * XLogFileNameP(TimeLineID tli, XLogSegNo segno)
Definition: xlog.c:10166
void XLogSetReplicationSlotMinimumLSN(XLogRecPtr lsn)
Definition: xlog.c:2654
void XLogSetAsyncXactLSN(XLogRecPtr record)
Definition: xlog.c:2613
void CheckXLogRemoved(XLogSegNo segno, TimeLineID tli)
Definition: xlog.c:3769
XLogRecPtr GetInsertRecPtr(void)
Definition: xlog.c:8245
bool reachedConsistency
Definition: xlog.c:834
Definition: dirent.c:25
bool wal_compression
Definition: xlog.c:99
void assign_checkpoint_completion_target(double newval, void *extra)
Definition: xlog.c:2252
bool * wal_consistency_checking
Definition: xlog.c:101
void UpdateControlFile(void)
Definition: xlog.c:4670
int XLogArchiveTimeout
Definition: xlog.c:93
int XLogArchiveMode
Definition: xlog.c:94
const char * xlog_identify(uint8 info)
Definition: xlogdesc.c:143
void InitXLOGAccess(void)
Definition: xlog.c:8176
HotStandbyState standbyState
Definition: xlog.c:197
SessionBackupState
Definition: xlog.h:305
PGDLLIMPORT int wal_level
Definition: xlog.c:104
bool EnableHotStandby
Definition: xlog.c:96
static char * buf
Definition: pg_test_fsync.c:67
XLogRecPtr GetXLogInsertRecPtr(void)
Definition: xlog.c:11147
int XLOGbuffers
Definition: xlog.c:92
XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata, XLogRecPtr fpw_lsn, uint8 flags)
Definition: xlog.c:960
uint64 XLogSegNo
Definition: xlogdefs.h:34
unsigned int uint32
Definition: c.h:296
RecoveryTargetType
Definition: xlog.h:80
void RemovePromoteSignalFiles(void)
Definition: xlog.c:12111
int ckpt_segs_removed
Definition: xlog.h:208
bool log_checkpoints
Definition: xlog.c:102
XLogRecPtr GetFlushRecPtr(void)
Definition: xlog.c:8261
int ckpt_bufs_written
Definition: xlog.h:205
void StartupXLOG(void)
Definition: xlog.c:6264
int wal_segment_size
Definition: xlog.c:113
bool HotStandbyActiveInReplay(void)
Definition: xlog.c:8010
int CheckPointSegments
Definition: xlog.c:126
uintptr_t Datum
Definition: postgres.h:372
SessionBackupState get_backup_status(void)
Definition: xlog.c:10702
void issue_xlog_fsync(int fd, XLogSegNo segno)
Definition: xlog.c:10123
XLogRecPtr ProcLastRecPtr
Definition: xlog.c:338
bool InRecovery
Definition: xlog.c:194
TimestampTz GetCurrentChunkReplayStartTime(void)
Definition: xlog.c:6166
XLogRecPtr GetLastImportantRecPtr(void)
Definition: xlog.c:8279
int XLogFileInit(XLogSegNo segno, bool *use_existent, bool use_lock)
Definition: xlog.c:3160
int sync_method
Definition: xlog.c:103
uint64 XLogRecPtr
Definition: xlogdefs.h:21
XLogRecPtr do_pg_stop_backup(char *labelfile, bool waitforarchive, TimeLineID *stoptli_p)
Definition: xlog.c:10721
PGDLLIMPORT XLogRecPtr XactLastCommitEnd
Definition: xlog.c:340
void SetWalWriterSleeping(bool sleeping)
Definition: xlog.c:12147
void ShutdownXLOG(int code, Datum arg)
Definition: xlog.c:8360
XLogRecPtr GetFakeLSNForUnloggedRel(void)
Definition: xlog.c:4754
void do_pg_abort_backup(void)
Definition: xlog.c:11108
void assign_max_wal_size(int newval, void *extra)
Definition: xlog.c:2245
ArchiveMode
Definition: xlog.h:116
size_t Size
Definition: c.h:404
TimestampTz GetLatestXTime(void)
Definition: xlog.c:6136
TimestampTz ckpt_write_t
Definition: xlog.h:200
#define newval
void XLogRequestWalReceiverReply(void)
Definition: xlog.c:12158
XLogRecPtr XLogRestorePoint(const char *rpName)
Definition: xlog.c:9459
Size XLOGShmemSize(void)
Definition: xlog.c:4849
bool RecoveryInProgress(void)
Definition: xlog.c:7929
TimestampTz ckpt_sync_t
Definition: xlog.h:201
int ckpt_segs_added
Definition: xlog.h:207
void XLOGShmemInit(void)
Definition: xlog.c:4890
bool RecoveryIsPaused(void)
Definition: xlog.c:6005
static const unsigned __int64 epoch
Definition: gettimeofday.c:34
void * arg
CheckpointStatsData CheckpointStats
Definition: xlog.c:175
PGDLLIMPORT TimeLineID ThisTimeLineID
Definition: xlog.c:181
void GetFullPageWriteInfo(XLogRecPtr *RedoRecPtr_p, bool *doPageWrites_p)
Definition: xlog.c:8230
int wal_retrieve_retry_interval
Definition: xlog.c:107
void BootStrapXLOG(void)
Definition: xlog.c:5003
void XLogPutNextOid(Oid nextOid)
Definition: xlog.c:9404
Definition: pg_list.h:45
void GetXLogReceiptTime(TimestampTz *rtime, bool *fromStream)
Definition: xlog.c:6182
uint64 GetSystemIdentifier(void)
Definition: xlog.c:4718
TimestampTz ckpt_end_t
Definition: xlog.h:203
HotStandbyState
Definition: xlog.h:64
WalLevel
Definition: xlog.h:125
uint64 ckpt_longest_sync
Definition: xlog.h:212
char * XLogArchiveCommand
Definition: xlog.c:95