PostgreSQL Source Code  git master
walsummary.c File Reference
#include "postgres.h"
#include <sys/stat.h>
#include <unistd.h>
#include "access/xlog_internal.h"
#include "backup/walsummary.h"
#include "common/int.h"
#include "utils/wait_event.h"
Include dependency graph for walsummary.c:

Go to the source code of this file.

Functions

static bool IsWalSummaryFilename (char *filename)
 
static int ListComparatorForWalSummaryFiles (const ListCell *a, const ListCell *b)
 
ListGetWalSummaries (TimeLineID tli, XLogRecPtr start_lsn, XLogRecPtr end_lsn)
 
ListFilterWalSummaries (List *wslist, TimeLineID tli, XLogRecPtr start_lsn, XLogRecPtr end_lsn)
 
bool WalSummariesAreComplete (List *wslist, XLogRecPtr start_lsn, XLogRecPtr end_lsn, XLogRecPtr *missing_lsn)
 
File OpenWalSummaryFile (WalSummaryFile *ws, bool missing_ok)
 
void RemoveWalSummaryIfOlderThan (WalSummaryFile *ws, time_t cutoff_time)
 
int ReadWalSummary (void *wal_summary_io, void *data, int length)
 
int WriteWalSummary (void *wal_summary_io, void *data, int length)
 
void ReportWalSummaryError (void *callback_arg, char *fmt,...)
 

Function Documentation

◆ FilterWalSummaries()

List* FilterWalSummaries ( List wslist,
TimeLineID  tli,
XLogRecPtr  start_lsn,
XLogRecPtr  end_lsn 
)

Definition at line 100 of file walsummary.c.

102 {
103  List *result = NIL;
104  ListCell *lc;
105 
106  /* Loop over input. */
107  foreach(lc, wslist)
108  {
109  WalSummaryFile *ws = lfirst(lc);
110 
111  /* Skip if it doesn't match the filter criteria. */
112  if (tli != 0 && tli != ws->tli)
113  continue;
114  if (!XLogRecPtrIsInvalid(start_lsn) && start_lsn > ws->end_lsn)
115  continue;
116  if (!XLogRecPtrIsInvalid(end_lsn) && end_lsn < ws->start_lsn)
117  continue;
118 
119  /* Add it to the result list. */
120  result = lappend(result, ws);
121  }
122 
123  return result;
124 }
List * lappend(List *list, void *datum)
Definition: list.c:339
#define lfirst(lc)
Definition: pg_list.h:172
#define NIL
Definition: pg_list.h:68
Definition: pg_list.h:54
XLogRecPtr end_lsn
Definition: walsummary.h:30
TimeLineID tli
Definition: walsummary.h:31
#define XLogRecPtrIsInvalid(r)
Definition: xlogdefs.h:29

References WalSummaryFile::end_lsn, lappend(), lfirst, NIL, WalSummaryFile::tli, and XLogRecPtrIsInvalid.

Referenced by PrepareForIncrementalBackup().

◆ GetWalSummaries()

List* GetWalSummaries ( TimeLineID  tli,
XLogRecPtr  start_lsn,
XLogRecPtr  end_lsn 
)

Definition at line 43 of file walsummary.c.

44 {
45  DIR *sdir;
46  struct dirent *dent;
47  List *result = NIL;
48 
49  sdir = AllocateDir(XLOGDIR "/summaries");
50  while ((dent = ReadDir(sdir, XLOGDIR "/summaries")) != NULL)
51  {
52  WalSummaryFile *ws;
53  uint32 tmp[5];
54  TimeLineID file_tli;
55  XLogRecPtr file_start_lsn;
56  XLogRecPtr file_end_lsn;
57 
58  /* Decode filename, or skip if it's not in the expected format. */
59  if (!IsWalSummaryFilename(dent->d_name))
60  continue;
61  sscanf(dent->d_name, "%08X%08X%08X%08X%08X",
62  &tmp[0], &tmp[1], &tmp[2], &tmp[3], &tmp[4]);
63  file_tli = tmp[0];
64  file_start_lsn = ((uint64) tmp[1]) << 32 | tmp[2];
65  file_end_lsn = ((uint64) tmp[3]) << 32 | tmp[4];
66 
67  /* Skip if it doesn't match the filter criteria. */
68  if (tli != 0 && tli != file_tli)
69  continue;
70  if (!XLogRecPtrIsInvalid(start_lsn) && start_lsn >= file_end_lsn)
71  continue;
72  if (!XLogRecPtrIsInvalid(end_lsn) && end_lsn <= file_start_lsn)
73  continue;
74 
75  /* Add it to the list. */
76  ws = palloc(sizeof(WalSummaryFile));
77  ws->tli = file_tli;
78  ws->start_lsn = file_start_lsn;
79  ws->end_lsn = file_end_lsn;
80  result = lappend(result, ws);
81  }
82  FreeDir(sdir);
83 
84  return result;
85 }
unsigned int uint32
Definition: c.h:506
struct dirent * ReadDir(DIR *dir, const char *dirname)
Definition: fd.c:2909
int FreeDir(DIR *dir)
Definition: fd.c:2961
DIR * AllocateDir(const char *dirname)
Definition: fd.c:2843
void * palloc(Size size)
Definition: mcxt.c:1317
Definition: dirent.c:26
XLogRecPtr start_lsn
Definition: walsummary.h:29
Definition: dirent.h:10
char d_name[MAX_PATH]
Definition: dirent.h:15
static bool IsWalSummaryFilename(char *filename)
Definition: walsummary.c:263
#define XLOGDIR
uint64 XLogRecPtr
Definition: xlogdefs.h:21
uint32 TimeLineID
Definition: xlogdefs.h:59

References AllocateDir(), dirent::d_name, WalSummaryFile::end_lsn, FreeDir(), IsWalSummaryFilename(), lappend(), NIL, palloc(), ReadDir(), WalSummaryFile::start_lsn, WalSummaryFile::tli, XLOGDIR, and XLogRecPtrIsInvalid.

Referenced by GetOldestUnsummarizedLSN(), MaybeRemoveOldWalSummaries(), pg_available_wal_summaries(), and PrepareForIncrementalBackup().

◆ IsWalSummaryFilename()

static bool IsWalSummaryFilename ( char *  filename)
static

Definition at line 263 of file walsummary.c.

264 {
265  return strspn(filename, "0123456789ABCDEF") == 40 &&
266  strcmp(filename + 40, ".summary") == 0;
267 }
static char * filename
Definition: pg_dumpall.c:119

References filename.

Referenced by GetWalSummaries().

◆ ListComparatorForWalSummaryFiles()

static int ListComparatorForWalSummaryFiles ( const ListCell a,
const ListCell b 
)
static

Definition at line 347 of file walsummary.c.

348 {
349  WalSummaryFile *ws1 = lfirst(a);
350  WalSummaryFile *ws2 = lfirst(b);
351 
352  return pg_cmp_u64(ws1->start_lsn, ws2->start_lsn);
353 }
static int pg_cmp_u64(uint64 a, uint64 b)
Definition: int.h:501
int b
Definition: isn.c:70
int a
Definition: isn.c:69

References a, b, lfirst, pg_cmp_u64(), and WalSummaryFile::start_lsn.

Referenced by WalSummariesAreComplete().

◆ OpenWalSummaryFile()

File OpenWalSummaryFile ( WalSummaryFile ws,
bool  missing_ok 
)

Definition at line 205 of file walsummary.c.

206 {
207  char path[MAXPGPATH];
208  File file;
209 
210  snprintf(path, MAXPGPATH,
211  XLOGDIR "/summaries/%08X%08X%08X%08X%08X.summary",
212  ws->tli,
214  LSN_FORMAT_ARGS(ws->end_lsn));
215 
216  file = PathNameOpenFile(path, O_RDONLY);
217  if (file < 0 && (errno != EEXIST || !missing_ok))
218  ereport(ERROR,
220  errmsg("could not open file \"%s\": %m", path)));
221 
222  return file;
223 }
int errcode_for_file_access(void)
Definition: elog.c:878
int errmsg(const char *fmt,...)
Definition: elog.c:1068
#define ERROR
Definition: elog.h:39
#define ereport(elevel,...)
Definition: elog.h:149
File PathNameOpenFile(const char *fileName, int fileFlags)
Definition: fd.c:1575
int File
Definition: fd.h:51
#define MAXPGPATH
#define snprintf
Definition: port.h:238
#define LSN_FORMAT_ARGS(lsn)
Definition: xlogdefs.h:43

References WalSummaryFile::end_lsn, ereport, errcode_for_file_access(), errmsg(), ERROR, LSN_FORMAT_ARGS, MAXPGPATH, PathNameOpenFile(), snprintf, WalSummaryFile::start_lsn, WalSummaryFile::tli, and XLOGDIR.

Referenced by pg_wal_summary_contents(), and PrepareForIncrementalBackup().

◆ ReadWalSummary()

int ReadWalSummary ( void *  wal_summary_io,
void *  data,
int  length 
)

Definition at line 273 of file walsummary.c.

274 {
275  WalSummaryIO *io = wal_summary_io;
276  int nbytes;
277 
278  nbytes = FileRead(io->file, data, length, io->filepos,
279  WAIT_EVENT_WAL_SUMMARY_READ);
280  if (nbytes < 0)
281  ereport(ERROR,
283  errmsg("could not read file \"%s\": %m",
284  FilePathName(io->file))));
285 
286  io->filepos += nbytes;
287  return nbytes;
288 }
char * FilePathName(File file)
Definition: fd.c:2461
static ssize_t FileRead(File file, void *buffer, size_t amount, off_t offset, uint32 wait_event_info)
Definition: fd.h:196
const void * data
off_t filepos
Definition: walsummary.h:24

References data, ereport, errcode_for_file_access(), errmsg(), ERROR, WalSummaryIO::file, FilePathName(), WalSummaryIO::filepos, and FileRead().

Referenced by pg_wal_summary_contents(), and PrepareForIncrementalBackup().

◆ RemoveWalSummaryIfOlderThan()

void RemoveWalSummaryIfOlderThan ( WalSummaryFile ws,
time_t  cutoff_time 
)

Definition at line 230 of file walsummary.c.

231 {
232  char path[MAXPGPATH];
233  struct stat statbuf;
234 
235  snprintf(path, MAXPGPATH,
236  XLOGDIR "/summaries/%08X%08X%08X%08X%08X.summary",
237  ws->tli,
239  LSN_FORMAT_ARGS(ws->end_lsn));
240 
241  if (lstat(path, &statbuf) != 0)
242  {
243  if (errno == ENOENT)
244  return;
245  ereport(ERROR,
247  errmsg("could not stat file \"%s\": %m", path)));
248  }
249  if (statbuf.st_mtime >= cutoff_time)
250  return;
251  if (unlink(path) != 0)
252  ereport(ERROR,
254  errmsg("could not stat file \"%s\": %m", path)));
255  ereport(DEBUG2,
256  (errmsg_internal("removing file \"%s\"", path)));
257 }
int errmsg_internal(const char *fmt,...)
Definition: elog.c:1155
#define DEBUG2
Definition: elog.h:29
#define lstat(path, sb)
Definition: win32_port.h:285

References DEBUG2, WalSummaryFile::end_lsn, ereport, errcode_for_file_access(), errmsg(), errmsg_internal(), ERROR, LSN_FORMAT_ARGS, lstat, MAXPGPATH, snprintf, stat::st_mtime, WalSummaryFile::start_lsn, WalSummaryFile::tli, and XLOGDIR.

Referenced by MaybeRemoveOldWalSummaries().

◆ ReportWalSummaryError()

void ReportWalSummaryError ( void *  callback_arg,
char *  fmt,
  ... 
)

Definition at line 322 of file walsummary.c.

323 {
325  va_list ap;
326  int needed;
327 
329  for (;;)
330  {
331  va_start(ap, fmt);
332  needed = appendStringInfoVA(&buf, fmt, ap);
333  va_end(ap);
334  if (needed == 0)
335  break;
336  enlargeStringInfo(&buf, needed);
337  }
338  ereport(ERROR,
340  errmsg_internal("%s", buf.data));
341 }
int errcode(int sqlerrcode)
Definition: elog.c:855
static void const char * fmt
va_end(args)
va_start(args, fmt)
#define ERRCODE_DATA_CORRUPTED
Definition: pg_basebackup.c:41
static char * buf
Definition: pg_test_fsync.c:73
int appendStringInfoVA(StringInfo str, const char *fmt, va_list args)
Definition: stringinfo.c:139
void enlargeStringInfo(StringInfo str, int needed)
Definition: stringinfo.c:289
void initStringInfo(StringInfo str)
Definition: stringinfo.c:59

References appendStringInfoVA(), buf, enlargeStringInfo(), ereport, errcode(), ERRCODE_DATA_CORRUPTED, errmsg_internal(), ERROR, fmt, initStringInfo(), va_end(), and va_start().

Referenced by pg_wal_summary_contents(), and PrepareForIncrementalBackup().

◆ WalSummariesAreComplete()

bool WalSummariesAreComplete ( List wslist,
XLogRecPtr  start_lsn,
XLogRecPtr  end_lsn,
XLogRecPtr missing_lsn 
)

Definition at line 138 of file walsummary.c.

140 {
141  XLogRecPtr current_lsn = start_lsn;
142  ListCell *lc;
143 
144  /* Special case for empty list. */
145  if (wslist == NIL)
146  {
147  *missing_lsn = InvalidXLogRecPtr;
148  return false;
149  }
150 
151  /* Make a private copy of the list and sort it by start LSN. */
152  wslist = list_copy(wslist);
154 
155  /*
156  * Consider summary files in order of increasing start_lsn, advancing the
157  * known-summarized range from start_lsn toward end_lsn.
158  *
159  * Normally, the summary files should cover non-overlapping WAL ranges,
160  * but this algorithm is intended to be correct even in case of overlap.
161  */
162  foreach(lc, wslist)
163  {
164  WalSummaryFile *ws = lfirst(lc);
165 
166  if (ws->start_lsn > current_lsn)
167  {
168  /* We found a gap. */
169  break;
170  }
171  if (ws->end_lsn > current_lsn)
172  {
173  /*
174  * Next summary extends beyond end of previous summary, so extend
175  * the end of the range known to be summarized.
176  */
177  current_lsn = ws->end_lsn;
178 
179  /*
180  * If the range we know to be summarized has reached the required
181  * end LSN, we have proved completeness.
182  */
183  if (current_lsn >= end_lsn)
184  return true;
185  }
186  }
187 
188  /*
189  * We either ran out of summary files without reaching the end LSN, or we
190  * hit a gap in the sequence that resulted in us bailing out of the loop
191  * above.
192  */
193  *missing_lsn = current_lsn;
194  return false;
195 }
void list_sort(List *list, list_sort_comparator cmp)
Definition: list.c:1674
List * list_copy(const List *oldlist)
Definition: list.c:1573
static int ListComparatorForWalSummaryFiles(const ListCell *a, const ListCell *b)
Definition: walsummary.c:347
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28

References WalSummaryFile::end_lsn, InvalidXLogRecPtr, lfirst, list_copy(), list_sort(), ListComparatorForWalSummaryFiles(), NIL, and WalSummaryFile::start_lsn.

Referenced by PrepareForIncrementalBackup().

◆ WriteWalSummary()

int WriteWalSummary ( void *  wal_summary_io,
void *  data,
int  length 
)

Definition at line 294 of file walsummary.c.

295 {
296  WalSummaryIO *io = wal_summary_io;
297  int nbytes;
298 
299  nbytes = FileWrite(io->file, data, length, io->filepos,
300  WAIT_EVENT_WAL_SUMMARY_WRITE);
301  if (nbytes < 0)
302  ereport(ERROR,
304  errmsg("could not write file \"%s\": %m",
305  FilePathName(io->file))));
306  if (nbytes != length)
307  ereport(ERROR,
309  errmsg("could not write file \"%s\": wrote only %d of %d bytes at offset %u",
310  FilePathName(io->file), nbytes,
311  length, (unsigned) io->filepos),
312  errhint("Check free disk space.")));
313 
314  io->filepos += nbytes;
315  return nbytes;
316 }
int errhint(const char *fmt,...)
Definition: elog.c:1315
static ssize_t FileWrite(File file, const void *buffer, size_t amount, off_t offset, uint32 wait_event_info)
Definition: fd.h:208

References data, ereport, errcode_for_file_access(), errhint(), errmsg(), ERROR, WalSummaryIO::file, FilePathName(), WalSummaryIO::filepos, and FileWrite().

Referenced by SummarizeWAL().