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 { 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_IMMEDIATE 87 } RecoveryTargetType; 88 89 extern XLogRecPtr ProcLastRecPtr; 90 extern XLogRecPtr XactLastRecEnd; 91 extern PGDLLIMPORT XLogRecPtr XactLastCommitEnd; 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 { 123 WAL_LEVEL_MINIMAL = 0, 124 WAL_LEVEL_REPLICA, 125 WAL_LEVEL_LOGICAL 126 } WalLevel; 127 128 /* Recovery states */ 129 typedef enum RecoveryState 130 { 131 RECOVERY_STATE_CRASH = 0, /* crash recovery */ 132 RECOVERY_STATE_ARCHIVE, /* archive recovery */ 133 RECOVERY_STATE_DONE /* currently in production */ 134 } RecoveryState; 135 136 extern PGDLLIMPORT int wal_level; 137 138 /* Is WAL archiving enabled (always or only while server is running normally)? */ 139 #define XLogArchivingActive() \ 140 (AssertMacro(XLogArchiveMode == ARCHIVE_MODE_OFF || wal_level >= WAL_LEVEL_REPLICA), XLogArchiveMode > ARCHIVE_MODE_OFF) 141 /* Is WAL archiving enabled always (even during recovery)? */ 142 #define XLogArchivingAlways() \ 143 (AssertMacro(XLogArchiveMode == ARCHIVE_MODE_OFF || wal_level >= WAL_LEVEL_REPLICA), XLogArchiveMode == ARCHIVE_MODE_ALWAYS) 144 #define XLogArchiveCommandSet() (XLogArchiveCommand[0] != '\0') 145 146 /* 147 * Is WAL-logging necessary for archival or log-shipping, or can we skip 148 * WAL-logging if we fsync() the data before committing instead? 149 */ 150 #define XLogIsNeeded() (wal_level >= WAL_LEVEL_REPLICA) 151 152 /* 153 * Is a full-page image needed for hint bit updates? 154 * 155 * Normally, we don't WAL-log hint bit updates, but if checksums are enabled, 156 * we have to protect them against torn page writes. When you only set 157 * individual bits on a page, it's still consistent no matter what combination 158 * of the bits make it to disk, but the checksum wouldn't match. Also WAL-log 159 * them if forced by wal_log_hints=on. 160 */ 161 #define XLogHintBitIsNeeded() (DataChecksumsEnabled() || wal_log_hints) 162 163 /* Do we need to WAL-log information required only for Hot Standby and logical replication? */ 164 #define XLogStandbyInfoActive() (wal_level >= WAL_LEVEL_REPLICA) 165 166 /* Do we need to WAL-log information required only for logical replication? */ 167 #define XLogLogicalInfoActive() (wal_level >= WAL_LEVEL_LOGICAL) 168 169 #ifdef WAL_DEBUG 170 extern bool XLOG_DEBUG; 171 #endif 172 173 /* 174 * OR-able request flag bits for checkpoints. The "cause" bits are used only 175 * for logging purposes. Note: the flags must be defined so that it's 176 * sensible to OR together request flags arising from different requestors. 177 */ 178 179 /* These directly affect the behavior of CreateCheckPoint and subsidiaries */ 180 #define CHECKPOINT_IS_SHUTDOWN 0x0001 /* Checkpoint is for shutdown */ 181 #define CHECKPOINT_END_OF_RECOVERY 0x0002 /* Like shutdown checkpoint, 182 * but issued at end of WAL 183 * recovery */ 184 #define CHECKPOINT_IMMEDIATE 0x0004 /* Do it without delays */ 185 #define CHECKPOINT_FORCE 0x0008 /* Force even if no activity */ 186 #define CHECKPOINT_FLUSH_ALL 0x0010 /* Flush all pages, including those 187 * belonging to unlogged tables */ 188 /* These are important to RequestCheckpoint */ 189 #define CHECKPOINT_WAIT 0x0020 /* Wait for completion */ 190 /* These indicate the cause of a checkpoint request */ 191 #define CHECKPOINT_CAUSE_XLOG 0x0040 /* XLOG consumption */ 192 #define CHECKPOINT_CAUSE_TIME 0x0080 /* Elapsed time */ 193 /* We set this to ensure that ckpt_flags is not 0 if a request has been made */ 194 #define CHECKPOINT_REQUESTED 0x0100 /* Checkpoint request has been made */ 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 216 * the entire sync phase. */ 217 } CheckpointStatsData; 218 219 extern CheckpointStatsData CheckpointStats; 220 221 struct XLogRecData; 222 223 extern XLogRecPtr XLogInsertRecord(struct XLogRecData *rdata, XLogRecPtr fpw_lsn); 224 extern void XLogFlush(XLogRecPtr RecPtr); 225 extern bool XLogBackgroundFlush(void); 226 extern bool XLogNeedsFlush(XLogRecPtr RecPtr); 227 extern int XLogFileInit(XLogSegNo segno, bool *use_existent, bool use_lock); 228 extern int XLogFileOpen(XLogSegNo segno); 229 230 extern void CheckXLogRemoved(XLogSegNo segno, TimeLineID tli); 231 extern XLogSegNo XLogGetLastRemovedSegno(void); 232 extern void XLogSetAsyncXactLSN(XLogRecPtr record); 233 extern void XLogSetReplicationSlotMinimumLSN(XLogRecPtr lsn); 234 235 extern void xlog_redo(XLogReaderState *record); 236 extern void xlog_desc(StringInfo buf, XLogReaderState *record); 237 extern const char *xlog_identify(uint8 info); 238 239 extern void issue_xlog_fsync(int fd, XLogSegNo segno); 240 241 extern bool RecoveryInProgress(void); 242 extern RecoveryState GetRecoveryState(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 bool DataChecksumsEnabled(void); 259 extern XLogRecPtr GetFakeLSNForUnloggedRel(void); 260 extern Size XLOGShmemSize(void); 261 extern void XLOGShmemInit(void); 262 extern void BootStrapXLOG(void); 263 extern void StartupXLOG(void); 264 extern void ShutdownXLOG(int code, Datum arg); 265 extern void InitXLOGAccess(void); 266 extern void CreateCheckPoint(int flags); 267 extern bool CreateRestartPoint(int flags); 268 extern void XLogPutNextOid(Oid nextOid); 269 extern XLogRecPtr XLogRestorePoint(const char *rpName); 270 extern void UpdateFullPageWrites(void); 271 extern void GetFullPageWriteInfo(XLogRecPtr *RedoRecPtr_p, bool *doPageWrites_p); 272 extern XLogRecPtr GetRedoRecPtr(void); 273 extern XLogRecPtr GetInsertRecPtr(void); 274 extern XLogRecPtr GetFlushRecPtr(void); 275 extern void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch); 276 extern void RemovePromoteSignalFiles(void); 277 278 extern bool CheckPromoteSignal(void); 279 extern void WakeupRecovery(void); 280 extern void SetWalWriterSleeping(bool sleeping); 281 282 extern void XLogRequestWalReceiverReply(void); 283 284 extern void assign_max_wal_size(int newval, void *extra); 285 extern void assign_checkpoint_completion_target(double newval, void *extra); 286 287 /* 288 * Routines to start, stop, and get status of a base backup. 289 */ 290 291 /* 292 * Session-level status of base backups 293 * 294 * This is used in parallel with the shared memory status to control parallel 295 * execution of base backup functions for a given session, be it a backend 296 * dedicated to replication or a normal backend connected to a database. The 297 * update of the session-level status happens at the same time as the shared 298 * memory counters to keep a consistent global and local state of the backups 299 * running. 300 */ 301 typedef enum SessionBackupState 302 { 303 SESSION_BACKUP_NONE, 304 SESSION_BACKUP_EXCLUSIVE, 305 SESSION_BACKUP_NON_EXCLUSIVE 306 } SessionBackupState; 307 308 extern XLogRecPtr do_pg_start_backup(const char *backupidstr, bool fast, 309 TimeLineID *starttli_p, StringInfo labelfile, DIR *tblspcdir, 310 List **tablespaces, StringInfo tblspcmapfile, bool infotbssize, 311 bool needtblspcmapfile); 312 extern XLogRecPtr do_pg_stop_backup(char *labelfile, bool waitforarchive, 313 TimeLineID *stoptli_p); 314 extern void do_pg_abort_backup(void); 315 extern SessionBackupState get_backup_status(void); 316 317 /* File path names (all relative to $PGDATA) */ 318 #define BACKUP_LABEL_FILE "backup_label" 319 #define BACKUP_LABEL_OLD "backup_label.old" 320 321 #define TABLESPACE_MAP "tablespace_map" 322 #define TABLESPACE_MAP_OLD "tablespace_map.old" 323 324 #endif /* XLOG_H */ 325