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 { 66 STANDBY_DISABLED, 67 STANDBY_INITIALIZED, 68 STANDBY_SNAPSHOT_PENDING, 69 STANDBY_SNAPSHOT_READY 70 } HotStandbyState; 71 72 extern HotStandbyState standbyState; 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 { 82 RECOVERY_TARGET_UNSET, 83 RECOVERY_TARGET_XID, 84 RECOVERY_TARGET_TIME, 85 RECOVERY_TARGET_NAME, 86 RECOVERY_TARGET_LSN, 87 RECOVERY_TARGET_IMMEDIATE 88 } RecoveryTargetType; 89 90 extern XLogRecPtr ProcLastRecPtr; 91 extern XLogRecPtr XactLastRecEnd; 92 extern PGDLLIMPORT XLogRecPtr XactLastCommitEnd; 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; 109 extern char *wal_consistency_checking_string; 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 { 126 WAL_LEVEL_MINIMAL = 0, 127 WAL_LEVEL_REPLICA, 128 WAL_LEVEL_LOGICAL 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. */ 216 } CheckpointStatsData; 217 218 extern CheckpointStatsData CheckpointStats; 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); 232 extern XLogSegNo XLogGetLastRemovedSegno(void); 233 extern void XLogSetAsyncXactLSN(XLogRecPtr record); 234 extern void XLogSetReplicationSlotMinimumLSN(XLogRecPtr lsn); 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); 253 extern TimestampTz GetCurrentChunkReplayStartTime(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); 260 extern XLogRecPtr GetFakeLSNForUnloggedRel(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); 276 extern XLogRecPtr GetLastImportantRecPtr(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 { 305 SESSION_BACKUP_NONE, 306 SESSION_BACKUP_EXCLUSIVE, 307 SESSION_BACKUP_NON_EXCLUSIVE 308 } SessionBackupState; 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); 317 extern SessionBackupState get_backup_status(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 */ 327