src/include/access/timeline.h

   1 /*
   2  * timeline.h
   3  *
   4  * Functions for reading and writing timeline history files.
   5  *
   6  * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  * src/include/access/timeline.h
  10  */
  11 #ifndef TIMELINE_H
  12 #define TIMELINE_H
  13
  14 #include "access/xlogdefs.h"
  15 #include "nodes/pg_list.h"
  16
  17 /*
  18  * A list of these structs describes the timeline history of the server. Each
  19  * TimeLineHistoryEntry represents a piece of WAL belonging to the history,
  20  * from newest to oldest. All WAL locations between 'begin' and 'end' belong to
  21  * the timeline represented by the entry. Together the 'begin' and 'end'
  22  * pointers of all the entries form a contiguous line from beginning of time
  23  * to infinity.
  24  */
  25 typedef struct
  26 {
  27         TimeLineID      tli;
  28         XLogRecPtr      begin;                  /* inclusive */
  29         XLogRecPtr      end;                    /* exclusive, InvalidXLogRecPtr means infinity */
  30 } TimeLineHistoryEntry;
  31
  32 extern List *readTimeLineHistory(TimeLineID targetTLI);
  33 extern bool existsTimeLineHistory(TimeLineID probeTLI);
  34 extern TimeLineID findNewestTimeLine(TimeLineID startTLI);
  35 extern void writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI,
  36                                                                  XLogRecPtr switchpoint, char *reason);
  37 extern void writeTimeLineHistoryFile(TimeLineID tli, char *content, int size);
  38 extern void restoreTimeLineHistoryFiles(TimeLineID begin, TimeLineID end);
  39 extern bool tliInHistory(TimeLineID tli, List *expectedTLEs);
  40 extern TimeLineID tliOfPointInHistory(XLogRecPtr ptr, List *history);
  41 extern XLogRecPtr tliSwitchPoint(TimeLineID tli, List *history,
  42                                                                  TimeLineID *nextTLI);
  43
  44 #endif                                                  /* TIMELINE_H */