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xlog.h
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1 /*
2  * xlog.h
3  *
4  * PostgreSQL transaction log manager
5  *
6  * Portions Copyright (c) 1996-2015, 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 {
88 
91 
92 extern bool reachedConsistency;
93 
94 /* these variables are GUC parameters related to XLOG */
95 extern int min_wal_size;
96 extern int max_wal_size;
97 extern int wal_keep_segments;
98 extern int XLOGbuffers;
99 extern int XLogArchiveTimeout;
100 extern int wal_retrieve_retry_interval;
101 extern char *XLogArchiveCommand;
102 extern bool EnableHotStandby;
103 extern bool fullPageWrites;
104 extern bool wal_log_hints;
105 extern bool wal_compression;
106 extern bool log_checkpoints;
107 
108 extern int CheckPointSegments;
109 
110 /* Archive modes */
111 typedef enum ArchiveMode
112 {
113  ARCHIVE_MODE_OFF = 0, /* disabled */
114  ARCHIVE_MODE_ON, /* enabled while server is running normally */
115  ARCHIVE_MODE_ALWAYS /* enabled always (even during recovery) */
116 } ArchiveMode;
117 extern int XLogArchiveMode;
118 
119 /* WAL levels */
120 typedef enum WalLevel
121 {
126 } WalLevel;
127 extern int wal_level;
128 
129 /* Is WAL archiving enabled (always or only while server is running normally)? */
130 #define XLogArchivingActive() \
131  (XLogArchiveMode > ARCHIVE_MODE_OFF && wal_level >= WAL_LEVEL_ARCHIVE)
132 /* Is WAL archiving enabled always (even during recovery)? */
133 #define XLogArchivingAlways() \
134  (XLogArchiveMode == ARCHIVE_MODE_ALWAYS && wal_level >= WAL_LEVEL_ARCHIVE)
135 #define XLogArchiveCommandSet() (XLogArchiveCommand[0] != '\0')
136 
137 /*
138  * Is WAL-logging necessary for archival or log-shipping, or can we skip
139  * WAL-logging if we fsync() the data before committing instead?
140  */
141 #define XLogIsNeeded() (wal_level >= WAL_LEVEL_ARCHIVE)
142 
143 /*
144  * Is a full-page image needed for hint bit updates?
145  *
146  * Normally, we don't WAL-log hint bit updates, but if checksums are enabled,
147  * we have to protect them against torn page writes. When you only set
148  * individual bits on a page, it's still consistent no matter what combination
149  * of the bits make it to disk, but the checksum wouldn't match. Also WAL-log
150  * them if forced by wal_log_hints=on.
151  */
152 #define XLogHintBitIsNeeded() (DataChecksumsEnabled() || wal_log_hints)
153 
154 /* Do we need to WAL-log information required only for Hot Standby and logical replication? */
155 #define XLogStandbyInfoActive() (wal_level >= WAL_LEVEL_HOT_STANDBY)
156 
157 /* Do we need to WAL-log information required only for logical replication? */
158 #define XLogLogicalInfoActive() (wal_level >= WAL_LEVEL_LOGICAL)
159 
160 #ifdef WAL_DEBUG
161 extern bool XLOG_DEBUG;
162 #endif
163 
164 /*
165  * OR-able request flag bits for checkpoints. The "cause" bits are used only
166  * for logging purposes. Note: the flags must be defined so that it's
167  * sensible to OR together request flags arising from different requestors.
168  */
169 
170 /* These directly affect the behavior of CreateCheckPoint and subsidiaries */
171 #define CHECKPOINT_IS_SHUTDOWN 0x0001 /* Checkpoint is for shutdown */
172 #define CHECKPOINT_END_OF_RECOVERY 0x0002 /* Like shutdown checkpoint,
173  * but issued at end of WAL
174  * recovery */
175 #define CHECKPOINT_IMMEDIATE 0x0004 /* Do it without delays */
176 #define CHECKPOINT_FORCE 0x0008 /* Force even if no activity */
177 #define CHECKPOINT_FLUSH_ALL 0x0010 /* Flush all pages, including those
178  * belonging to unlogged tables */
179 /* These are important to RequestCheckpoint */
180 #define CHECKPOINT_WAIT 0x0020 /* Wait for completion */
181 /* These indicate the cause of a checkpoint request */
182 #define CHECKPOINT_CAUSE_XLOG 0x0040 /* XLOG consumption */
183 #define CHECKPOINT_CAUSE_TIME 0x0080 /* Elapsed time */
184 
185 /* Checkpoint statistics */
186 typedef struct CheckpointStatsData
187 {
188  TimestampTz ckpt_start_t; /* start of checkpoint */
189  TimestampTz ckpt_write_t; /* start of flushing buffers */
190  TimestampTz ckpt_sync_t; /* start of fsyncs */
191  TimestampTz ckpt_sync_end_t; /* end of fsyncs */
192  TimestampTz ckpt_end_t; /* end of checkpoint */
193 
194  int ckpt_bufs_written; /* # of buffers written */
195 
196  int ckpt_segs_added; /* # of new xlog segments created */
197  int ckpt_segs_removed; /* # of xlog segments deleted */
198  int ckpt_segs_recycled; /* # of xlog segments recycled */
199 
200  int ckpt_sync_rels; /* # of relations synced */
201  uint64 ckpt_longest_sync; /* Longest sync for one relation */
202  uint64 ckpt_agg_sync_time; /* The sum of all the individual sync
203  * times, which is not necessarily the
204  * same as the total elapsed time for
205  * the entire sync phase. */
207 
209 
210 struct XLogRecData;
211 
212 extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata, XLogRecPtr fpw_lsn);
213 extern void XLogFlush(XLogRecPtr RecPtr);
214 extern bool XLogBackgroundFlush(void);
215 extern bool XLogNeedsFlush(XLogRecPtr RecPtr);
216 extern int XLogFileInit(XLogSegNo segno, bool *use_existent, bool use_lock);
217 extern int XLogFileOpen(XLogSegNo segno);
218 
219 extern void CheckXLogRemoved(XLogSegNo segno, TimeLineID tli);
221 extern void XLogSetAsyncXactLSN(XLogRecPtr record);
223 
224 extern void xlog_redo(XLogReaderState *record);
225 extern void xlog_desc(StringInfo buf, XLogReaderState *record);
226 extern const char *xlog_identify(uint8 info);
227 
228 extern void issue_xlog_fsync(int fd, XLogSegNo segno);
229 
230 extern bool RecoveryInProgress(void);
231 extern bool HotStandbyActive(void);
232 extern bool HotStandbyActiveInReplay(void);
233 extern bool XLogInsertAllowed(void);
234 extern void GetXLogReceiptTime(TimestampTz *rtime, bool *fromStream);
235 extern XLogRecPtr GetXLogReplayRecPtr(TimeLineID *replayTLI);
236 extern XLogRecPtr GetXLogInsertRecPtr(void);
237 extern XLogRecPtr GetXLogWriteRecPtr(void);
238 extern bool RecoveryIsPaused(void);
239 extern void SetRecoveryPause(bool recoveryPause);
240 extern TimestampTz GetLatestXTime(void);
242 extern char *XLogFileNameP(TimeLineID tli, XLogSegNo segno);
243 
244 extern void UpdateControlFile(void);
245 extern uint64 GetSystemIdentifier(void);
246 extern bool DataChecksumsEnabled(void);
248 extern Size XLOGShmemSize(void);
249 extern void XLOGShmemInit(void);
250 extern void BootStrapXLOG(void);
251 extern void StartupXLOG(void);
252 extern void ShutdownXLOG(int code, Datum arg);
253 extern void InitXLOGAccess(void);
254 extern void CreateCheckPoint(int flags);
255 extern bool CreateRestartPoint(int flags);
256 extern void XLogPutNextOid(Oid nextOid);
257 extern XLogRecPtr XLogRestorePoint(const char *rpName);
258 extern void UpdateFullPageWrites(void);
259 extern void GetFullPageWriteInfo(XLogRecPtr *RedoRecPtr_p, bool *doPageWrites_p);
260 extern XLogRecPtr GetRedoRecPtr(void);
261 extern XLogRecPtr GetInsertRecPtr(void);
262 extern XLogRecPtr GetFlushRecPtr(void);
263 extern void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch);
264 
265 extern bool CheckPromoteSignal(void);
266 extern void WakeupRecovery(void);
267 extern void SetWalWriterSleeping(bool sleeping);
268 
269 extern void assign_max_wal_size(int newval, void *extra);
270 extern void assign_checkpoint_completion_target(double newval, void *extra);
271 
272 /*
273  * Starting/stopping a base backup
274  */
275 extern XLogRecPtr do_pg_start_backup(const char *backupidstr, bool fast,
276  TimeLineID *starttli_p, char **labelfile, DIR *tblspcdir,
277  List **tablespaces, char **tblspcmapfile, bool infotbssize,
278  bool needtblspcmapfile);
279 extern XLogRecPtr do_pg_stop_backup(char *labelfile, bool waitforarchive,
280  TimeLineID *stoptli_p);
281 extern void do_pg_abort_backup(void);
282 
283 /* File path names (all relative to $PGDATA) */
284 #define BACKUP_LABEL_FILE "backup_label"
285 #define BACKUP_LABEL_OLD "backup_label.old"
286 
287 #define TABLESPACE_MAP "tablespace_map"
288 #define TABLESPACE_MAP_OLD "tablespace_map.old"
289 
290 #endif /* XLOG_H */
void CreateCheckPoint(int flags)
Definition: xlog.c:8139
int wal_keep_segments
Definition: xlog.c:87
struct CheckpointStatsData CheckpointStatsData
XLogRecPtr GetXLogWriteRecPtr(void)
Definition: xlog.c:10669
uint64 ckpt_agg_sync_time
Definition: xlog.h:202
TimestampTz ckpt_sync_end_t
Definition: xlog.h:191
bool CreateRestartPoint(int flags)
Definition: xlog.c:8696
int ckpt_sync_rels
Definition: xlog.h:200
bool XLogInsertAllowed(void)
Definition: xlog.c:7621
bool XLogNeedsFlush(XLogRecPtr RecPtr)
Definition: xlog.c:2842
uint32 TimeLineID
Definition: xlogdefs.h:45
XLogRecPtr do_pg_start_backup(const char *backupidstr, bool fast, TimeLineID *starttli_p, char **labelfile, DIR *tblspcdir, List **tablespaces, char **tblspcmapfile, bool infotbssize, bool needtblspcmapfile)
Definition: xlog.c:9795
XLogRecPtr GetRedoRecPtr(void)
Definition: xlog.c:7814
bool DataChecksumsEnabled(void)
Definition: xlog.c:4487
void WakeupRecovery(void)
Definition: xlog.c:11607
uint32 TransactionId
Definition: c.h:382
void XLogFlush(XLogRecPtr RecPtr)
Definition: xlog.c:2569
void xlog_desc(StringInfo buf, XLogReaderState *record)
Definition: xlogdesc.c:35
bool HotStandbyActive(void)
Definition: xlog.c:7582
int XLogFileOpen(XLogSegNo segno)
Definition: xlog.c:3295
TimestampTz ckpt_start_t
Definition: xlog.h:188
XLogRecPtr XactLastRecEnd
Definition: xlog.c:326
bool wal_log_hints
Definition: xlog.c:94
unsigned char uint8
Definition: c.h:252
int ckpt_segs_recycled
Definition: xlog.h:198
bool fullPageWrites
Definition: xlog.c:93
XLogSegNo XLogGetLastRemovedSegno(void)
Definition: xlog.c:3566
void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch)
Definition: xlog.c:7909
unsigned int Oid
Definition: postgres_ext.h:31
void SetRecoveryPause(bool recoveryPause)
Definition: xlog.c:5640
bool CheckPromoteSignal(void)
Definition: xlog.c:11591
XLogRecPtr GetXLogReplayRecPtr(TimeLineID *replayTLI)
Definition: xlog.c:10634
static int fd(const char *x, int i)
Definition: preproc-init.c:105
void UpdateFullPageWrites(void)
Definition: xlog.c:9115
bool XLogBackgroundFlush(void)
Definition: xlog.c:2751
#define PGDLLIMPORT
Definition: c.h:1032
void xlog_redo(XLogReaderState *record)
Definition: xlog.c:9219
char * XLogFileNameP(TimeLineID tli, XLogSegNo segno)
Definition: xlog.c:9748
int max_wal_size
Definition: xlog.c:85
void XLogSetReplicationSlotMinimumLSN(XLogRecPtr lsn)
Definition: xlog.c:2460
void XLogSetAsyncXactLSN(XLogRecPtr record)
Definition: xlog.c:2419
void CheckXLogRemoved(XLogSegNo segno, TimeLineID tli)
Definition: xlog.c:3538
double TimestampTz
Definition: timestamp.h:51
XLogRecPtr GetInsertRecPtr(void)
Definition: xlog.c:7857
bool reachedConsistency
Definition: xlog.c:773
Definition: dirent.c:25
bool wal_compression
Definition: xlog.c:95
void assign_checkpoint_completion_target(double newval, void *extra)
Definition: xlog.c:2055
void UpdateControlFile(void)
Definition: xlog.c:4432
int XLogArchiveTimeout
Definition: xlog.c:89
int XLogArchiveMode
Definition: xlog.c:90
const char * xlog_identify(uint8 info)
Definition: xlogdesc.c:142
void InitXLOGAccess(void)
Definition: xlog.c:7791
HotStandbyState standbyState
Definition: xlog.c:189
bool EnableHotStandby
Definition: xlog.c:92
static char * buf
Definition: pg_test_fsync.c:65
XLogRecPtr GetXLogInsertRecPtr(void)
Definition: xlog.c:10653
int XLOGbuffers
Definition: xlog.c:88
uint64 XLogSegNo
Definition: xlogdefs.h:34
unsigned int uint32
Definition: c.h:254
RecoveryTargetType
Definition: xlog.h:80
XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata, XLogRecPtr fpw_lsn)
Definition: xlog.c:894
int ckpt_segs_removed
Definition: xlog.h:197
bool log_checkpoints
Definition: xlog.c:96
int min_wal_size
Definition: xlog.c:86
XLogRecPtr GetFlushRecPtr(void)
Definition: xlog.c:7873
int ckpt_bufs_written
Definition: xlog.h:194
void StartupXLOG(void)
Definition: xlog.c:5894
bool HotStandbyActiveInReplay(void)
Definition: xlog.c:7607
int CheckPointSegments
Definition: xlog.c:118
uintptr_t Datum
Definition: postgres.h:374
void issue_xlog_fsync(int fd, XLogSegNo segno)
Definition: xlog.c:9705
bool InRecovery
Definition: xlog.c:186
TimestampTz GetCurrentChunkReplayStartTime(void)
Definition: xlog.c:5784
int XLogFileInit(XLogSegNo segno, bool *use_existent, bool use_lock)
Definition: xlog.c:2918
int sync_method
Definition: xlog.c:97
uint64 XLogRecPtr
Definition: xlogdefs.h:21
XLogRecPtr do_pg_stop_backup(char *labelfile, bool waitforarchive, TimeLineID *stoptli_p)
Definition: xlog.c:10258
PGDLLIMPORT XLogRecPtr XactLastCommitEnd
Definition: xlog.c:327
void SetWalWriterSleeping(bool sleeping)
Definition: xlog.c:11616
void ShutdownXLOG(int code, Datum arg)
Definition: xlog.c:7939
XLogRecPtr GetFakeLSNForUnloggedRel(void)
Definition: xlog.c:4503
void do_pg_abort_backup(void)
Definition: xlog.c:10614
void assign_max_wal_size(int newval, void *extra)
Definition: xlog.c:2048
ArchiveMode
Definition: xlog.h:111
size_t Size
Definition: c.h:341
TimestampTz GetLatestXTime(void)
Definition: xlog.c:5754
TimestampTz ckpt_write_t
Definition: xlog.h:189
#define newval
XLogRecPtr XLogRestorePoint(const char *rpName)
Definition: xlog.c:9034
Size XLOGShmemSize(void)
Definition: xlog.c:4578
bool RecoveryInProgress(void)
Definition: xlog.c:7526
TimestampTz ckpt_sync_t
Definition: xlog.h:190
int ckpt_segs_added
Definition: xlog.h:196
void XLOGShmemInit(void)
Definition: xlog.c:4619
bool RecoveryIsPaused(void)
Definition: xlog.c:5628
int wal_level
Definition: xlog.c:98
static const unsigned __int64 epoch
Definition: gettimeofday.c:34
void * arg
CheckpointStatsData CheckpointStats
Definition: xlog.c:167
PGDLLIMPORT TimeLineID ThisTimeLineID
Definition: xlog.c:173
void GetFullPageWriteInfo(XLogRecPtr *RedoRecPtr_p, bool *doPageWrites_p)
Definition: xlog.c:7842
int wal_retrieve_retry_interval
Definition: xlog.c:101
void BootStrapXLOG(void)
Definition: xlog.c:4731
void XLogPutNextOid(Oid nextOid)
Definition: xlog.c:8982
Definition: pg_list.h:45
void GetXLogReceiptTime(TimestampTz *rtime, bool *fromStream)
Definition: xlog.c:5800
uint64 GetSystemIdentifier(void)
Definition: xlog.c:4477
TimestampTz ckpt_end_t
Definition: xlog.h:192
HotStandbyState
Definition: xlog.h:64
WalLevel
Definition: xlog.h:120
uint64 ckpt_longest_sync
Definition: xlog.h:201
char * XLogArchiveCommand
Definition: xlog.c:91