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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) 1996-2016, 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 
92 
93 extern bool reachedConsistency;
94 
95 /* these variables are GUC parameters related to XLOG */
96 extern int min_wal_size;
97 extern int max_wal_size;
98 extern int wal_keep_segments;
99 extern int XLOGbuffers;
100 extern int XLogArchiveTimeout;
101 extern int wal_retrieve_retry_interval;
102 extern char *XLogArchiveCommand;
103 extern bool EnableHotStandby;
104 extern bool fullPageWrites;
105 extern bool wal_log_hints;
106 extern bool wal_compression;
107 extern bool log_checkpoints;
108 
109 extern int CheckPointSegments;
110 
111 /* Archive modes */
112 typedef enum ArchiveMode
113 {
114  ARCHIVE_MODE_OFF = 0, /* disabled */
115  ARCHIVE_MODE_ON, /* enabled while server is running normally */
116  ARCHIVE_MODE_ALWAYS /* enabled always (even during recovery) */
117 } ArchiveMode;
118 extern int XLogArchiveMode;
119 
120 /* WAL levels */
121 typedef enum WalLevel
122 {
126 } WalLevel;
127 
128 extern PGDLLIMPORT int wal_level;
129 
130 /* Is WAL archiving enabled (always or only while server is running normally)? */
131 #define XLogArchivingActive() \
132  (AssertMacro(XLogArchiveMode == ARCHIVE_MODE_OFF || wal_level >= WAL_LEVEL_REPLICA), XLogArchiveMode > ARCHIVE_MODE_OFF)
133 /* Is WAL archiving enabled always (even during recovery)? */
134 #define XLogArchivingAlways() \
135  (AssertMacro(XLogArchiveMode == ARCHIVE_MODE_OFF || wal_level >= WAL_LEVEL_REPLICA), XLogArchiveMode == ARCHIVE_MODE_ALWAYS)
136 #define XLogArchiveCommandSet() (XLogArchiveCommand[0] != '\0')
137 
138 /*
139  * Is WAL-logging necessary for archival or log-shipping, or can we skip
140  * WAL-logging if we fsync() the data before committing instead?
141  */
142 #define XLogIsNeeded() (wal_level >= WAL_LEVEL_REPLICA)
143 
144 /*
145  * Is a full-page image needed for hint bit updates?
146  *
147  * Normally, we don't WAL-log hint bit updates, but if checksums are enabled,
148  * we have to protect them against torn page writes. When you only set
149  * individual bits on a page, it's still consistent no matter what combination
150  * of the bits make it to disk, but the checksum wouldn't match. Also WAL-log
151  * them if forced by wal_log_hints=on.
152  */
153 #define XLogHintBitIsNeeded() (DataChecksumsEnabled() || wal_log_hints)
154 
155 /* Do we need to WAL-log information required only for Hot Standby and logical replication? */
156 #define XLogStandbyInfoActive() (wal_level >= WAL_LEVEL_REPLICA)
157 
158 /* Do we need to WAL-log information required only for logical replication? */
159 #define XLogLogicalInfoActive() (wal_level >= WAL_LEVEL_LOGICAL)
160 
161 #ifdef WAL_DEBUG
162 extern bool XLOG_DEBUG;
163 #endif
164 
165 /*
166  * OR-able request flag bits for checkpoints. The "cause" bits are used only
167  * for logging purposes. Note: the flags must be defined so that it's
168  * sensible to OR together request flags arising from different requestors.
169  */
170 
171 /* These directly affect the behavior of CreateCheckPoint and subsidiaries */
172 #define CHECKPOINT_IS_SHUTDOWN 0x0001 /* Checkpoint is for shutdown */
173 #define CHECKPOINT_END_OF_RECOVERY 0x0002 /* Like shutdown checkpoint,
174  * but issued at end of WAL
175  * recovery */
176 #define CHECKPOINT_IMMEDIATE 0x0004 /* Do it without delays */
177 #define CHECKPOINT_FORCE 0x0008 /* Force even if no activity */
178 #define CHECKPOINT_FLUSH_ALL 0x0010 /* Flush all pages, including those
179  * belonging to unlogged tables */
180 /* These are important to RequestCheckpoint */
181 #define CHECKPOINT_WAIT 0x0020 /* Wait for completion */
182 /* These indicate the cause of a checkpoint request */
183 #define CHECKPOINT_CAUSE_XLOG 0x0040 /* XLOG consumption */
184 #define CHECKPOINT_CAUSE_TIME 0x0080 /* Elapsed time */
185 
186 /* Checkpoint statistics */
187 typedef struct CheckpointStatsData
188 {
189  TimestampTz ckpt_start_t; /* start of checkpoint */
190  TimestampTz ckpt_write_t; /* start of flushing buffers */
191  TimestampTz ckpt_sync_t; /* start of fsyncs */
192  TimestampTz ckpt_sync_end_t; /* end of fsyncs */
193  TimestampTz ckpt_end_t; /* end of checkpoint */
194 
195  int ckpt_bufs_written; /* # of buffers written */
196 
197  int ckpt_segs_added; /* # of new xlog segments created */
198  int ckpt_segs_removed; /* # of xlog segments deleted */
199  int ckpt_segs_recycled; /* # of xlog segments recycled */
200 
201  int ckpt_sync_rels; /* # of relations synced */
202  uint64 ckpt_longest_sync; /* Longest sync for one relation */
203  uint64 ckpt_agg_sync_time; /* The sum of all the individual sync
204  * times, which is not necessarily the
205  * same as the total elapsed time for
206  * the entire sync phase. */
208 
210 
211 struct XLogRecData;
212 
213 extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata, XLogRecPtr fpw_lsn);
214 extern void XLogFlush(XLogRecPtr RecPtr);
215 extern bool XLogBackgroundFlush(void);
216 extern bool XLogNeedsFlush(XLogRecPtr RecPtr);
217 extern int XLogFileInit(XLogSegNo segno, bool *use_existent, bool use_lock);
218 extern int XLogFileOpen(XLogSegNo segno);
219 
220 extern void CheckXLogRemoved(XLogSegNo segno, TimeLineID tli);
222 extern void XLogSetAsyncXactLSN(XLogRecPtr record);
224 
225 extern void xlog_redo(XLogReaderState *record);
226 extern void xlog_desc(StringInfo buf, XLogReaderState *record);
227 extern const char *xlog_identify(uint8 info);
228 
229 extern void issue_xlog_fsync(int fd, XLogSegNo segno);
230 
231 extern bool RecoveryInProgress(void);
232 extern bool HotStandbyActive(void);
233 extern bool HotStandbyActiveInReplay(void);
234 extern bool XLogInsertAllowed(void);
235 extern void GetXLogReceiptTime(TimestampTz *rtime, bool *fromStream);
236 extern XLogRecPtr GetXLogReplayRecPtr(TimeLineID *replayTLI);
237 extern XLogRecPtr GetXLogInsertRecPtr(void);
238 extern XLogRecPtr GetXLogWriteRecPtr(void);
239 extern bool RecoveryIsPaused(void);
240 extern void SetRecoveryPause(bool recoveryPause);
241 extern TimestampTz GetLatestXTime(void);
243 extern char *XLogFileNameP(TimeLineID tli, XLogSegNo segno);
244 
245 extern void UpdateControlFile(void);
246 extern uint64 GetSystemIdentifier(void);
247 extern bool DataChecksumsEnabled(void);
249 extern Size XLOGShmemSize(void);
250 extern void XLOGShmemInit(void);
251 extern void BootStrapXLOG(void);
252 extern void StartupXLOG(void);
253 extern void ShutdownXLOG(int code, Datum arg);
254 extern void InitXLOGAccess(void);
255 extern void CreateCheckPoint(int flags);
256 extern bool CreateRestartPoint(int flags);
257 extern void XLogPutNextOid(Oid nextOid);
258 extern XLogRecPtr XLogRestorePoint(const char *rpName);
259 extern void UpdateFullPageWrites(void);
260 extern void GetFullPageWriteInfo(XLogRecPtr *RedoRecPtr_p, bool *doPageWrites_p);
261 extern XLogRecPtr GetRedoRecPtr(void);
262 extern XLogRecPtr GetInsertRecPtr(void);
263 extern XLogRecPtr GetFlushRecPtr(void);
264 extern void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch);
265 extern void RemovePromoteSignalFiles(void);
266 
267 extern bool CheckPromoteSignal(void);
268 extern void WakeupRecovery(void);
269 extern void SetWalWriterSleeping(bool sleeping);
270 
271 extern void XLogRequestWalReceiverReply(void);
272 
273 extern void assign_max_wal_size(int newval, void *extra);
274 extern void assign_checkpoint_completion_target(double newval, void *extra);
275 
276 /*
277  * Starting/stopping a base backup
278  */
279 extern XLogRecPtr do_pg_start_backup(const char *backupidstr, bool fast,
280  TimeLineID *starttli_p, StringInfo labelfile, DIR *tblspcdir,
281  List **tablespaces, StringInfo tblspcmapfile, bool infotbssize,
282  bool needtblspcmapfile);
283 extern XLogRecPtr do_pg_stop_backup(char *labelfile, bool waitforarchive,
284  TimeLineID *stoptli_p);
285 extern void do_pg_abort_backup(void);
286 
287 /* File path names (all relative to $PGDATA) */
288 #define BACKUP_LABEL_FILE "backup_label"
289 #define BACKUP_LABEL_OLD "backup_label.old"
290 
291 #define TABLESPACE_MAP "tablespace_map"
292 #define TABLESPACE_MAP_OLD "tablespace_map.old"
293 
294 #endif /* XLOG_H */
void CreateCheckPoint(int flags)
Definition: xlog.c:8152
int wal_keep_segments
Definition: xlog.c:88
struct CheckpointStatsData CheckpointStatsData
XLogRecPtr GetXLogWriteRecPtr(void)
Definition: xlog.c:10649
uint64 ckpt_agg_sync_time
Definition: xlog.h:203
TimestampTz ckpt_sync_end_t
Definition: xlog.h:192
bool CreateRestartPoint(int flags)
Definition: xlog.c:8698
int ckpt_sync_rels
Definition: xlog.h:201
bool XLogInsertAllowed(void)
Definition: xlog.c:7640
bool XLogNeedsFlush(XLogRecPtr RecPtr)
Definition: xlog.c:2889
uint32 TimeLineID
Definition: xlogdefs.h:45
XLogRecPtr GetRedoRecPtr(void)
Definition: xlog.c:7833
bool DataChecksumsEnabled(void)
Definition: xlog.c:4516
void WakeupRecovery(void)
Definition: xlog.c:11605
uint32 TransactionId
Definition: c.h:393
void XLogFlush(XLogRecPtr RecPtr)
Definition: xlog.c:2569
void xlog_desc(StringInfo buf, XLogReaderState *record)
Definition: xlogdesc.c:36
bool HotStandbyActive(void)
Definition: xlog.c:7601
int XLogFileOpen(XLogSegNo segno)
Definition: xlog.c:3324
TimestampTz ckpt_start_t
Definition: xlog.h:189
XLogRecPtr XactLastRecEnd
Definition: xlog.c:326
bool wal_log_hints
Definition: xlog.c:95
unsigned char uint8
Definition: c.h:263
int ckpt_segs_recycled
Definition: xlog.h:199
bool fullPageWrites
Definition: xlog.c:94
XLogSegNo XLogGetLastRemovedSegno(void)
Definition: xlog.c:3595
void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch)
Definition: xlog.c:7926
unsigned int Oid
Definition: postgres_ext.h:31
void SetRecoveryPause(bool recoveryPause)
Definition: xlog.c:5665
bool CheckPromoteSignal(void)
Definition: xlog.c:11589
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:9768
XLogRecPtr GetXLogReplayRecPtr(TimeLineID *replayTLI)
Definition: xlog.c:10614
static int fd(const char *x, int i)
Definition: preproc-init.c:105
void UpdateFullPageWrites(void)
Definition: xlog.c:9102
bool XLogBackgroundFlush(void)
Definition: xlog.c:2758
#define PGDLLIMPORT
Definition: c.h:1043
void xlog_redo(XLogReaderState *record)
Definition: xlog.c:9206
char * XLogFileNameP(TimeLineID tli, XLogSegNo segno)
Definition: xlog.c:9721
int max_wal_size
Definition: xlog.c:86
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:3567
double TimestampTz
Definition: timestamp.h:51
XLogRecPtr GetInsertRecPtr(void)
Definition: xlog.c:7876
bool reachedConsistency
Definition: xlog.c:773
Definition: dirent.c:25
bool wal_compression
Definition: xlog.c:96
void assign_checkpoint_completion_target(double newval, void *extra)
Definition: xlog.c:2055
void UpdateControlFile(void)
Definition: xlog.c:4461
int XLogArchiveTimeout
Definition: xlog.c:90
int XLogArchiveMode
Definition: xlog.c:91
const char * xlog_identify(uint8 info)
Definition: xlogdesc.c:143
void InitXLOGAccess(void)
Definition: xlog.c:7810
HotStandbyState standbyState
Definition: xlog.c:190
PGDLLIMPORT int wal_level
Definition: xlog.c:99
bool EnableHotStandby
Definition: xlog.c:93
static char * buf
Definition: pg_test_fsync.c:65
XLogRecPtr GetXLogInsertRecPtr(void)
Definition: xlog.c:10633
int XLOGbuffers
Definition: xlog.c:89
uint64 XLogSegNo
Definition: xlogdefs.h:34
unsigned int uint32
Definition: c.h:265
RecoveryTargetType
Definition: xlog.h:80
XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata, XLogRecPtr fpw_lsn)
Definition: xlog.c:894
void RemovePromoteSignalFiles(void)
Definition: xlog.c:11578
int ckpt_segs_removed
Definition: xlog.h:198
bool log_checkpoints
Definition: xlog.c:97
int min_wal_size
Definition: xlog.c:87
XLogRecPtr GetFlushRecPtr(void)
Definition: xlog.c:7892
int ckpt_bufs_written
Definition: xlog.h:195
void StartupXLOG(void)
Definition: xlog.c:5911
bool HotStandbyActiveInReplay(void)
Definition: xlog.c:7626
int CheckPointSegments
Definition: xlog.c:119
uintptr_t Datum
Definition: postgres.h:374
void issue_xlog_fsync(int fd, XLogSegNo segno)
Definition: xlog.c:9678
XLogRecPtr ProcLastRecPtr
Definition: xlog.c:325
bool InRecovery
Definition: xlog.c:187
TimestampTz GetCurrentChunkReplayStartTime(void)
Definition: xlog.c:5813
int XLogFileInit(XLogSegNo segno, bool *use_existent, bool use_lock)
Definition: xlog.c:2965
int sync_method
Definition: xlog.c:98
uint64 XLogRecPtr
Definition: xlogdefs.h:21
XLogRecPtr do_pg_stop_backup(char *labelfile, bool waitforarchive, TimeLineID *stoptli_p)
Definition: xlog.c:10229
PGDLLIMPORT XLogRecPtr XactLastCommitEnd
Definition: xlog.c:327
void SetWalWriterSleeping(bool sleeping)
Definition: xlog.c:11614
void ShutdownXLOG(int code, Datum arg)
Definition: xlog.c:7956
XLogRecPtr GetFakeLSNForUnloggedRel(void)
Definition: xlog.c:4532
void do_pg_abort_backup(void)
Definition: xlog.c:10594
void assign_max_wal_size(int newval, void *extra)
Definition: xlog.c:2048
ArchiveMode
Definition: xlog.h:112
size_t Size
Definition: c.h:352
TimestampTz GetLatestXTime(void)
Definition: xlog.c:5783
TimestampTz ckpt_write_t
Definition: xlog.h:190
#define newval
void XLogRequestWalReceiverReply(void)
Definition: xlog.c:11625
XLogRecPtr XLogRestorePoint(const char *rpName)
Definition: xlog.c:9021
Size XLOGShmemSize(void)
Definition: xlog.c:4607
bool RecoveryInProgress(void)
Definition: xlog.c:7545
TimestampTz ckpt_sync_t
Definition: xlog.h:191
int ckpt_segs_added
Definition: xlog.h:197
void XLOGShmemInit(void)
Definition: xlog.c:4648
bool RecoveryIsPaused(void)
Definition: xlog.c:5653
static const unsigned __int64 epoch
Definition: gettimeofday.c:34
void * arg
CheckpointStatsData CheckpointStats
Definition: xlog.c:168
PGDLLIMPORT TimeLineID ThisTimeLineID
Definition: xlog.c:174
void GetFullPageWriteInfo(XLogRecPtr *RedoRecPtr_p, bool *doPageWrites_p)
Definition: xlog.c:7861
int wal_retrieve_retry_interval
Definition: xlog.c:102
void BootStrapXLOG(void)
Definition: xlog.c:4757
void XLogPutNextOid(Oid nextOid)
Definition: xlog.c:8969
Definition: pg_list.h:45
void GetXLogReceiptTime(TimestampTz *rtime, bool *fromStream)
Definition: xlog.c:5829
uint64 GetSystemIdentifier(void)
Definition: xlog.c:4506
TimestampTz ckpt_end_t
Definition: xlog.h:193
HotStandbyState
Definition: xlog.h:64
WalLevel
Definition: xlog.h:121
uint64 ckpt_longest_sync
Definition: xlog.h:202
char * XLogArchiveCommand
Definition: xlog.c:92