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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 min_wal_size_mb;
98 extern int max_wal_size_mb;
99 extern int wal_keep_segments;
100 extern int XLOGbuffers;
101 extern int XLogArchiveTimeout;
102 extern int wal_retrieve_retry_interval;
103 extern char *XLogArchiveCommand;
104 extern bool EnableHotStandby;
105 extern bool fullPageWrites;
106 extern bool wal_log_hints;
107 extern bool wal_compression;
108 extern bool *wal_consistency_checking;
110 extern bool log_checkpoints;
111 
112 extern int CheckPointSegments;
113 
114 /* Archive modes */
115 typedef enum ArchiveMode
116 {
117  ARCHIVE_MODE_OFF = 0, /* disabled */
118  ARCHIVE_MODE_ON, /* enabled while server is running normally */
119  ARCHIVE_MODE_ALWAYS /* enabled always (even during recovery) */
120 } ArchiveMode;
121 extern int XLogArchiveMode;
122 
123 /* WAL levels */
124 typedef enum WalLevel
125 {
129 } WalLevel;
130 
131 extern PGDLLIMPORT int wal_level;
132 
133 /* Is WAL archiving enabled (always or only while server is running normally)? */
134 #define XLogArchivingActive() \
135  (AssertMacro(XLogArchiveMode == ARCHIVE_MODE_OFF || wal_level >= WAL_LEVEL_REPLICA), XLogArchiveMode > ARCHIVE_MODE_OFF)
136 /* Is WAL archiving enabled always (even during recovery)? */
137 #define XLogArchivingAlways() \
138  (AssertMacro(XLogArchiveMode == ARCHIVE_MODE_OFF || wal_level >= WAL_LEVEL_REPLICA), XLogArchiveMode == ARCHIVE_MODE_ALWAYS)
139 #define XLogArchiveCommandSet() (XLogArchiveCommand[0] != '\0')
140 
141 /*
142  * Is WAL-logging necessary for archival or log-shipping, or can we skip
143  * WAL-logging if we fsync() the data before committing instead?
144  */
145 #define XLogIsNeeded() (wal_level >= WAL_LEVEL_REPLICA)
146 
147 /*
148  * Is a full-page image needed for hint bit updates?
149  *
150  * Normally, we don't WAL-log hint bit updates, but if checksums are enabled,
151  * we have to protect them against torn page writes. When you only set
152  * individual bits on a page, it's still consistent no matter what combination
153  * of the bits make it to disk, but the checksum wouldn't match. Also WAL-log
154  * them if forced by wal_log_hints=on.
155  */
156 #define XLogHintBitIsNeeded() (DataChecksumsEnabled() || wal_log_hints)
157 
158 /* Do we need to WAL-log information required only for Hot Standby and logical replication? */
159 #define XLogStandbyInfoActive() (wal_level >= WAL_LEVEL_REPLICA)
160 
161 /* Do we need to WAL-log information required only for logical replication? */
162 #define XLogLogicalInfoActive() (wal_level >= WAL_LEVEL_LOGICAL)
163 
164 #ifdef WAL_DEBUG
165 extern bool XLOG_DEBUG;
166 #endif
167 
168 /*
169  * OR-able request flag bits for checkpoints. The "cause" bits are used only
170  * for logging purposes. Note: the flags must be defined so that it's
171  * sensible to OR together request flags arising from different requestors.
172  */
173 
174 /* These directly affect the behavior of CreateCheckPoint and subsidiaries */
175 #define CHECKPOINT_IS_SHUTDOWN 0x0001 /* Checkpoint is for shutdown */
176 #define CHECKPOINT_END_OF_RECOVERY 0x0002 /* Like shutdown checkpoint, but
177  * issued at end of WAL recovery */
178 #define CHECKPOINT_IMMEDIATE 0x0004 /* Do it without delays */
179 #define CHECKPOINT_FORCE 0x0008 /* Force even if no activity */
180 #define CHECKPOINT_FLUSH_ALL 0x0010 /* Flush all pages, including those
181  * belonging to unlogged tables */
182 /* These are important to RequestCheckpoint */
183 #define CHECKPOINT_WAIT 0x0020 /* Wait for completion */
184 /* These indicate the cause of a checkpoint request */
185 #define CHECKPOINT_CAUSE_XLOG 0x0040 /* XLOG consumption */
186 #define CHECKPOINT_CAUSE_TIME 0x0080 /* Elapsed time */
187 
188 /*
189  * Flag bits for the record being inserted, set using XLogSetRecordFlags().
190  */
191 #define XLOG_INCLUDE_ORIGIN 0x01 /* include the replication origin */
192 #define XLOG_MARK_UNIMPORTANT 0x02 /* record not important for durability */
193 
194 
195 /* Checkpoint statistics */
196 typedef struct CheckpointStatsData
197 {
198  TimestampTz ckpt_start_t; /* start of checkpoint */
199  TimestampTz ckpt_write_t; /* start of flushing buffers */
200  TimestampTz ckpt_sync_t; /* start of fsyncs */
201  TimestampTz ckpt_sync_end_t; /* end of fsyncs */
202  TimestampTz ckpt_end_t; /* end of checkpoint */
203 
204  int ckpt_bufs_written; /* # of buffers written */
205 
206  int ckpt_segs_added; /* # of new xlog segments created */
207  int ckpt_segs_removed; /* # of xlog segments deleted */
208  int ckpt_segs_recycled; /* # of xlog segments recycled */
209 
210  int ckpt_sync_rels; /* # of relations synced */
211  uint64 ckpt_longest_sync; /* Longest sync for one relation */
212  uint64 ckpt_agg_sync_time; /* The sum of all the individual sync
213  * times, which is not necessarily the
214  * same as the total elapsed time for the
215  * entire sync phase. */
217 
219 
220 struct XLogRecData;
221 
222 extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata,
223  XLogRecPtr fpw_lsn,
224  uint8 flags);
225 extern void XLogFlush(XLogRecPtr RecPtr);
226 extern bool XLogBackgroundFlush(void);
227 extern bool XLogNeedsFlush(XLogRecPtr RecPtr);
228 extern int XLogFileInit(XLogSegNo segno, bool *use_existent, bool use_lock);
229 extern int XLogFileOpen(XLogSegNo segno);
230 
231 extern void CheckXLogRemoved(XLogSegNo segno, TimeLineID tli);
233 extern void XLogSetAsyncXactLSN(XLogRecPtr record);
235 
236 extern void xlog_redo(XLogReaderState *record);
237 extern void xlog_desc(StringInfo buf, XLogReaderState *record);
238 extern const char *xlog_identify(uint8 info);
239 
240 extern void issue_xlog_fsync(int fd, XLogSegNo segno);
241 
242 extern bool RecoveryInProgress(void);
243 extern bool HotStandbyActive(void);
244 extern bool HotStandbyActiveInReplay(void);
245 extern bool XLogInsertAllowed(void);
246 extern void GetXLogReceiptTime(TimestampTz *rtime, bool *fromStream);
247 extern XLogRecPtr GetXLogReplayRecPtr(TimeLineID *replayTLI);
248 extern XLogRecPtr GetXLogInsertRecPtr(void);
249 extern XLogRecPtr GetXLogWriteRecPtr(void);
250 extern bool RecoveryIsPaused(void);
251 extern void SetRecoveryPause(bool recoveryPause);
252 extern TimestampTz GetLatestXTime(void);
254 extern char *XLogFileNameP(TimeLineID tli, XLogSegNo segno);
255 
256 extern void UpdateControlFile(void);
257 extern uint64 GetSystemIdentifier(void);
258 extern char *GetMockAuthenticationNonce(void);
259 extern bool DataChecksumsEnabled(void);
261 extern Size XLOGShmemSize(void);
262 extern void XLOGShmemInit(void);
263 extern void BootStrapXLOG(void);
264 extern void StartupXLOG(void);
265 extern void ShutdownXLOG(int code, Datum arg);
266 extern void InitXLOGAccess(void);
267 extern void CreateCheckPoint(int flags);
268 extern bool CreateRestartPoint(int flags);
269 extern void XLogPutNextOid(Oid nextOid);
270 extern XLogRecPtr XLogRestorePoint(const char *rpName);
271 extern void UpdateFullPageWrites(void);
272 extern void GetFullPageWriteInfo(XLogRecPtr *RedoRecPtr_p, bool *doPageWrites_p);
273 extern XLogRecPtr GetRedoRecPtr(void);
274 extern XLogRecPtr GetInsertRecPtr(void);
275 extern XLogRecPtr GetFlushRecPtr(void);
277 extern void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch);
278 extern void RemovePromoteSignalFiles(void);
279 
280 extern bool CheckPromoteSignal(void);
281 extern void WakeupRecovery(void);
282 extern void SetWalWriterSleeping(bool sleeping);
283 
284 extern void XLogRequestWalReceiverReply(void);
285 
286 extern void assign_max_wal_size(int newval, void *extra);
287 extern void assign_checkpoint_completion_target(double newval, void *extra);
288 
289 /*
290  * Routines to start, stop, and get status of a base backup.
291  */
292 
293 /*
294  * Session-level status of base backups
295  *
296  * This is used in parallel with the shared memory status to control parallel
297  * execution of base backup functions for a given session, be it a backend
298  * dedicated to replication or a normal backend connected to a database. The
299  * update of the session-level status happens at the same time as the shared
300  * memory counters to keep a consistent global and local state of the backups
301  * running.
302  */
303 typedef enum SessionBackupState
304 {
309 
310 extern XLogRecPtr do_pg_start_backup(const char *backupidstr, bool fast,
311  TimeLineID *starttli_p, StringInfo labelfile, DIR *tblspcdir,
312  List **tablespaces, StringInfo tblspcmapfile, bool infotbssize,
313  bool needtblspcmapfile);
314 extern XLogRecPtr do_pg_stop_backup(char *labelfile, bool waitforarchive,
315  TimeLineID *stoptli_p);
316 extern void do_pg_abort_backup(void);
318 
319 /* File path names (all relative to $PGDATA) */
320 #define BACKUP_LABEL_FILE "backup_label"
321 #define BACKUP_LABEL_OLD "backup_label.old"
322 
323 #define TABLESPACE_MAP "tablespace_map"
324 #define TABLESPACE_MAP_OLD "tablespace_map.old"
325 
326 #endif /* XLOG_H */
void CreateCheckPoint(int flags)
Definition: xlog.c:8533
int wal_keep_segments
Definition: xlog.c:91
struct CheckpointStatsData CheckpointStatsData
XLogRecPtr GetXLogWriteRecPtr(void)
Definition: xlog.c:11129
uint64 ckpt_agg_sync_time
Definition: xlog.h:212
TimestampTz ckpt_sync_end_t
Definition: xlog.h:201
bool CreateRestartPoint(int flags)
Definition: xlog.c:9080
int ckpt_sync_rels
Definition: xlog.h:210
bool XLogInsertAllowed(void)
Definition: xlog.c:7973
int min_wal_size_mb
Definition: xlog.c:90
bool XLogNeedsFlush(XLogRecPtr RecPtr)
Definition: xlog.c:3077
uint32 TimeLineID
Definition: xlogdefs.h:45
XLogRecPtr GetRedoRecPtr(void)
Definition: xlog.c:8168
bool DataChecksumsEnabled(void)
Definition: xlog.c:4715
void WakeupRecovery(void)
Definition: xlog.c:12102
uint32 TransactionId
Definition: c.h:397
void XLogFlush(XLogRecPtr RecPtr)
Definition: xlog.c:2757
void xlog_desc(StringInfo buf, XLogReaderState *record)
Definition: xlogdesc.c:36
bool HotStandbyActive(void)
Definition: xlog.c:7934
int64 TimestampTz
Definition: timestamp.h:39
int XLogFileOpen(XLogSegNo segno)
Definition: xlog.c:3522
TimestampTz ckpt_start_t
Definition: xlog.h:198
XLogRecPtr XactLastRecEnd
Definition: xlog.c:337
bool wal_log_hints
Definition: xlog.c:98
unsigned char uint8
Definition: c.h:266
char * GetMockAuthenticationNonce(void)
Definition: xlog.c:4705
int ckpt_segs_recycled
Definition: xlog.h:208
bool fullPageWrites
Definition: xlog.c:97
XLogSegNo XLogGetLastRemovedSegno(void)
Definition: xlog.c:3793
int max_wal_size_mb
Definition: xlog.c:89
void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch)
Definition: xlog.c:8296
char * wal_consistency_checking_string
Definition: xlog.c:100
unsigned int Oid
Definition: postgres_ext.h:31
void SetRecoveryPause(bool recoveryPause)
Definition: xlog.c:5947
bool CheckPromoteSignal(void)
Definition: xlog.c:12086
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:10183
XLogRecPtr GetXLogReplayRecPtr(TimeLineID *replayTLI)
Definition: xlog.c:11094
static int fd(const char *x, int i)
Definition: preproc-init.c:105
void UpdateFullPageWrites(void)
Definition: xlog.c:9510
bool XLogBackgroundFlush(void)
Definition: xlog.c:2946
#define PGDLLIMPORT
Definition: c.h:1063
void xlog_redo(XLogReaderState *record)
Definition: xlog.c:9614
char * XLogFileNameP(TimeLineID tli, XLogSegNo segno)
Definition: xlog.c:10136
void XLogSetReplicationSlotMinimumLSN(XLogRecPtr lsn)
Definition: xlog.c:2648
void XLogSetAsyncXactLSN(XLogRecPtr record)
Definition: xlog.c:2607
void CheckXLogRemoved(XLogSegNo segno, TimeLineID tli)
Definition: xlog.c:3765
XLogRecPtr GetInsertRecPtr(void)
Definition: xlog.c:8211
bool reachedConsistency
Definition: xlog.c:830
Definition: dirent.c:25
bool wal_compression
Definition: xlog.c:99
void assign_checkpoint_completion_target(double newval, void *extra)
Definition: xlog.c:2240
bool * wal_consistency_checking
Definition: xlog.c:101
void UpdateControlFile(void)
Definition: xlog.c:4646
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:8145
HotStandbyState standbyState
Definition: xlog.c:195
SessionBackupState
Definition: xlog.h:303
PGDLLIMPORT int wal_level
Definition: xlog.c:104
bool EnableHotStandby
Definition: xlog.c:96
static char * buf
Definition: pg_test_fsync.c:66
XLogRecPtr GetXLogInsertRecPtr(void)
Definition: xlog.c:11113
int XLOGbuffers
Definition: xlog.c:92
XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata, XLogRecPtr fpw_lsn, uint8 flags)
Definition: xlog.c:956
uint64 XLogSegNo
Definition: xlogdefs.h:34
unsigned int uint32
Definition: c.h:268
RecoveryTargetType
Definition: xlog.h:80
void RemovePromoteSignalFiles(void)
Definition: xlog.c:12075
int ckpt_segs_removed
Definition: xlog.h:207
bool log_checkpoints
Definition: xlog.c:102
XLogRecPtr GetFlushRecPtr(void)
Definition: xlog.c:8227
int ckpt_bufs_written
Definition: xlog.h:204
void StartupXLOG(void)
Definition: xlog.c:6194
bool HotStandbyActiveInReplay(void)
Definition: xlog.c:7959
int CheckPointSegments
Definition: xlog.c:124
uintptr_t Datum
Definition: postgres.h:372
SessionBackupState get_backup_status(void)
Definition: xlog.c:10672
void issue_xlog_fsync(int fd, XLogSegNo segno)
Definition: xlog.c:10093
XLogRecPtr ProcLastRecPtr
Definition: xlog.c:336
bool InRecovery
Definition: xlog.c:192
TimestampTz GetCurrentChunkReplayStartTime(void)
Definition: xlog.c:6096
XLogRecPtr GetLastImportantRecPtr(void)
Definition: xlog.c:8245
int XLogFileInit(XLogSegNo segno, bool *use_existent, bool use_lock)
Definition: xlog.c:3153
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:10691
PGDLLIMPORT XLogRecPtr XactLastCommitEnd
Definition: xlog.c:338
void SetWalWriterSleeping(bool sleeping)
Definition: xlog.c:12111
void ShutdownXLOG(int code, Datum arg)
Definition: xlog.c:8326
XLogRecPtr GetFakeLSNForUnloggedRel(void)
Definition: xlog.c:4731
void do_pg_abort_backup(void)
Definition: xlog.c:11074
void assign_max_wal_size(int newval, void *extra)
Definition: xlog.c:2233
ArchiveMode
Definition: xlog.h:115
size_t Size
Definition: c.h:356
TimestampTz GetLatestXTime(void)
Definition: xlog.c:6066
TimestampTz ckpt_write_t
Definition: xlog.h:199
#define newval
void XLogRequestWalReceiverReply(void)
Definition: xlog.c:12122
XLogRecPtr XLogRestorePoint(const char *rpName)
Definition: xlog.c:9429
Size XLOGShmemSize(void)
Definition: xlog.c:4806
bool RecoveryInProgress(void)
Definition: xlog.c:7878
TimestampTz ckpt_sync_t
Definition: xlog.h:200
int ckpt_segs_added
Definition: xlog.h:206
void XLOGShmemInit(void)
Definition: xlog.c:4847
bool RecoveryIsPaused(void)
Definition: xlog.c:5935
static const unsigned __int64 epoch
Definition: gettimeofday.c:34
void * arg
CheckpointStatsData CheckpointStats
Definition: xlog.c:173
PGDLLIMPORT TimeLineID ThisTimeLineID
Definition: xlog.c:179
void GetFullPageWriteInfo(XLogRecPtr *RedoRecPtr_p, bool *doPageWrites_p)
Definition: xlog.c:8196
int wal_retrieve_retry_interval
Definition: xlog.c:107
void BootStrapXLOG(void)
Definition: xlog.c:4951
void XLogPutNextOid(Oid nextOid)
Definition: xlog.c:9374
Definition: pg_list.h:45
void GetXLogReceiptTime(TimestampTz *rtime, bool *fromStream)
Definition: xlog.c:6112
uint64 GetSystemIdentifier(void)
Definition: xlog.c:4695
TimestampTz ckpt_end_t
Definition: xlog.h:202
HotStandbyState
Definition: xlog.h:64
WalLevel
Definition: xlog.h:124
uint64 ckpt_longest_sync
Definition: xlog.h:211
char * XLogArchiveCommand
Definition: xlog.c:95