Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * basebackup_incremental.c
4 : : * code for incremental backup support
5 : : *
6 : : * This code isn't actually in charge of taking an incremental backup;
7 : : * the actual construction of the incremental backup happens in
8 : : * basebackup.c. Here, we're concerned with providing the necessary
9 : : * supports for that operation. In particular, we need to parse the
10 : : * backup manifest supplied by the user taking the incremental backup
11 : : * and extract the required information from it.
12 : : *
13 : : * Portions Copyright (c) 2010-2026, PostgreSQL Global Development Group
14 : : *
15 : : * IDENTIFICATION
16 : : * src/backend/backup/basebackup_incremental.c
17 : : *
18 : : *-------------------------------------------------------------------------
19 : : */
20 : : #include "postgres.h"
21 : :
22 : : #include "access/timeline.h"
23 : : #include "access/xlog.h"
24 : : #include "backup/basebackup_incremental.h"
25 : : #include "backup/walsummary.h"
26 : : #include "common/blkreftable.h"
27 : : #include "common/hashfn.h"
28 : : #include "common/int.h"
29 : : #include "common/parse_manifest.h"
30 : : #include "postmaster/walsummarizer.h"
31 : :
32 : : #define BLOCKS_PER_READ 512
33 : :
34 : : /*
35 : : * We expect to find the last lines of the manifest, including the checksum,
36 : : * in the last MIN_CHUNK bytes of the manifest. We trigger an incremental
37 : : * parse step if we are about to overflow MAX_CHUNK bytes.
38 : : */
39 : : #define MIN_CHUNK 1024
40 : : #define MAX_CHUNK (128 * 1024)
41 : :
42 : : /*
43 : : * Details extracted from the WAL ranges present in the supplied backup manifest.
44 : : */
45 : : typedef struct
46 : : {
47 : : TimeLineID tli;
48 : : XLogRecPtr start_lsn;
49 : : XLogRecPtr end_lsn;
50 : : } backup_wal_range;
51 : :
52 : : /*
53 : : * Details extracted from the file list present in the supplied backup manifest.
54 : : */
55 : : typedef struct
56 : : {
57 : : uint32 status;
58 : : const char *path;
59 : : uint64 size;
60 : : } backup_file_entry;
61 : :
62 : : static uint32 hash_string_pointer(const char *s);
63 : : #define SH_PREFIX backup_file
64 : : #define SH_ELEMENT_TYPE backup_file_entry
65 : : #define SH_KEY_TYPE const char *
66 : : #define SH_KEY path
67 : : #define SH_HASH_KEY(tb, key) hash_string_pointer(key)
68 : : #define SH_EQUAL(tb, a, b) (strcmp(a, b) == 0)
69 : : #define SH_SCOPE static inline
70 : : #define SH_DECLARE
71 : : #define SH_DEFINE
72 : : #include "lib/simplehash.h"
73 : :
74 : : struct IncrementalBackupInfo
75 : : {
76 : : /* Memory context for this object and its subsidiary objects. */
77 : : MemoryContext mcxt;
78 : :
79 : : /* Temporary buffer for storing the manifest while parsing it. */
80 : : StringInfoData buf;
81 : :
82 : : /* WAL ranges extracted from the backup manifest. */
83 : : List *manifest_wal_ranges;
84 : :
85 : : /*
86 : : * Files extracted from the backup manifest.
87 : : *
88 : : * We don't really need this information, because we use WAL summaries to
89 : : * figure out what's changed. It would be unsafe to just rely on the list
90 : : * of files that existed before, because it's possible for a file to be
91 : : * removed and a new one created with the same name and different
92 : : * contents. In such cases, the whole file must still be sent. We can tell
93 : : * from the WAL summaries whether that happened, but not from the file
94 : : * list.
95 : : *
96 : : * Nonetheless, this data is useful for sanity checking. If a file that we
97 : : * think we shouldn't need to send is not present in the manifest for the
98 : : * prior backup, something has gone terribly wrong. We retain the file
99 : : * names and sizes, but not the checksums or last modified times, for
100 : : * which we have no use.
101 : : *
102 : : * One significant downside of storing this data is that it consumes
103 : : * memory. If that turns out to be a problem, we might have to decide not
104 : : * to retain this information, or to make it optional.
105 : : */
106 : : backup_file_hash *manifest_files;
107 : :
108 : : /*
109 : : * Block-reference table for the incremental backup.
110 : : *
111 : : * It's possible that storing the entire block-reference table in memory
112 : : * will be a problem for some users. The in-memory format that we're using
113 : : * here is pretty efficient, converging to little more than 1 bit per
114 : : * block for relation forks with large numbers of modified blocks. It's
115 : : * possible, however, that if you try to perform an incremental backup of
116 : : * a database with a sufficiently large number of relations on a
117 : : * sufficiently small machine, you could run out of memory here. If that
118 : : * turns out to be a problem in practice, we'll need to be more clever.
119 : : */
120 : : BlockRefTable *brtab;
121 : :
122 : : /*
123 : : * State object for incremental JSON parsing
124 : : */
125 : : JsonManifestParseIncrementalState *inc_state;
126 : : };
127 : :
128 : : static void manifest_process_version(JsonManifestParseContext *context,
129 : : int manifest_version);
130 : : static void manifest_process_system_identifier(JsonManifestParseContext *context,
131 : : uint64 manifest_system_identifier);
132 : : static void manifest_process_file(JsonManifestParseContext *context,
133 : : const char *pathname,
134 : : uint64 size,
135 : : pg_checksum_type checksum_type,
136 : : int checksum_length,
137 : : uint8 *checksum_payload);
138 : : static void manifest_process_wal_range(JsonManifestParseContext *context,
139 : : TimeLineID tli,
140 : : XLogRecPtr start_lsn,
141 : : XLogRecPtr end_lsn);
142 : : pg_noreturn static void manifest_report_error(JsonManifestParseContext *context,
143 : : const char *fmt,...)
144 : : pg_attribute_printf(2, 3);
145 : : static int compare_block_numbers(const void *a, const void *b);
146 : :
147 : : /*
148 : : * Create a new object for storing information extracted from the manifest
149 : : * supplied when creating an incremental backup.
150 : : */
151 : : IncrementalBackupInfo *
816 rhaas@postgresql.org 152 :CBC 11 : CreateIncrementalBackupInfo(MemoryContext mcxt)
153 : : {
154 : : IncrementalBackupInfo *ib;
155 : : MemoryContext oldcontext;
156 : : JsonManifestParseContext *context;
157 : :
158 : 11 : oldcontext = MemoryContextSwitchTo(mcxt);
159 : :
95 michael@paquier.xyz 160 :GNC 11 : ib = palloc0_object(IncrementalBackupInfo);
816 rhaas@postgresql.org 161 :CBC 11 : ib->mcxt = mcxt;
162 : 11 : initStringInfo(&ib->buf);
163 : :
164 : : /*
165 : : * It's hard to guess how many files a "typical" installation will have in
166 : : * the data directory, but a fresh initdb creates almost 1000 files as of
167 : : * this writing, so it seems to make sense for our estimate to
168 : : * substantially higher.
169 : : */
170 : 11 : ib->manifest_files = backup_file_create(mcxt, 10000, NULL);
171 : :
95 michael@paquier.xyz 172 :GNC 11 : context = palloc0_object(JsonManifestParseContext);
173 : : /* Parse the manifest. */
734 andrew@dunslane.net 174 :CBC 11 : context->private_data = ib;
175 : 11 : context->version_cb = manifest_process_version;
176 : 11 : context->system_identifier_cb = manifest_process_system_identifier;
177 : 11 : context->per_file_cb = manifest_process_file;
178 : 11 : context->per_wal_range_cb = manifest_process_wal_range;
179 : 11 : context->error_cb = manifest_report_error;
180 : :
181 : 11 : ib->inc_state = json_parse_manifest_incremental_init(context);
182 : :
816 rhaas@postgresql.org 183 : 11 : MemoryContextSwitchTo(oldcontext);
184 : :
185 : 11 : return ib;
186 : : }
187 : :
188 : : /*
189 : : * Before taking an incremental backup, the caller must supply the backup
190 : : * manifest from a prior backup. Each chunk of manifest data received
191 : : * from the client should be passed to this function.
192 : : */
193 : : void
194 : 33 : AppendIncrementalManifestData(IncrementalBackupInfo *ib, const char *data,
195 : : int len)
196 : : {
197 : : MemoryContext oldcontext;
198 : :
199 : : /* Switch to our memory context. */
200 : 33 : oldcontext = MemoryContextSwitchTo(ib->mcxt);
201 : :
734 andrew@dunslane.net 202 [ + + + + ]: 33 : if (ib->buf.len > MIN_CHUNK && ib->buf.len + len > MAX_CHUNK)
203 : : {
204 : : /*
205 : : * time for an incremental parse. We'll do all but the last MIN_CHUNK
206 : : * so that we have enough left for the final piece.
207 : : */
474 alvherre@alvh.no-ip. 208 : 11 : json_parse_manifest_incremental_chunk(ib->inc_state, ib->buf.data,
209 : 11 : ib->buf.len - MIN_CHUNK, false);
210 : : /* now remove what we just parsed */
734 andrew@dunslane.net 211 : 10 : memmove(ib->buf.data, ib->buf.data + (ib->buf.len - MIN_CHUNK),
212 : : MIN_CHUNK + 1);
213 : 10 : ib->buf.len = MIN_CHUNK;
214 : : }
215 : :
816 rhaas@postgresql.org 216 : 32 : appendBinaryStringInfo(&ib->buf, data, len);
217 : :
218 : : /* Switch back to previous memory context. */
219 : 32 : MemoryContextSwitchTo(oldcontext);
220 : 32 : }
221 : :
222 : : /*
223 : : * Finalize an IncrementalBackupInfo object after all manifest data has
224 : : * been supplied via calls to AppendIncrementalManifestData.
225 : : */
226 : : void
227 : 10 : FinalizeIncrementalManifest(IncrementalBackupInfo *ib)
228 : : {
229 : : MemoryContext oldcontext;
230 : :
231 : : /* Switch to our memory context. */
232 : 10 : oldcontext = MemoryContextSwitchTo(ib->mcxt);
233 : :
234 : : /* Parse the last chunk of the manifest */
474 alvherre@alvh.no-ip. 235 : 10 : json_parse_manifest_incremental_chunk(ib->inc_state, ib->buf.data,
236 : 10 : ib->buf.len, true);
237 : :
238 : : /* Done with the buffer, so release memory. */
816 rhaas@postgresql.org 239 : 10 : pfree(ib->buf.data);
240 : 10 : ib->buf.data = NULL;
241 : :
242 : : /* Done with inc_state, so release that memory too */
705 andrew@dunslane.net 243 : 10 : json_parse_manifest_incremental_shutdown(ib->inc_state);
244 : :
245 : : /* Switch back to previous memory context. */
816 rhaas@postgresql.org 246 : 10 : MemoryContextSwitchTo(oldcontext);
247 : 10 : }
248 : :
249 : : /*
250 : : * Prepare to take an incremental backup.
251 : : *
252 : : * Before this function is called, AppendIncrementalManifestData and
253 : : * FinalizeIncrementalManifest should have already been called to pass all
254 : : * the manifest data to this object.
255 : : *
256 : : * This function performs sanity checks on the data extracted from the
257 : : * manifest and figures out for which WAL ranges we need summaries, and
258 : : * whether those summaries are available. Then, it reads and combines the
259 : : * data from those summary files. It also updates the backup_state with the
260 : : * reference TLI and LSN for the prior backup.
261 : : */
262 : : void
263 : 10 : PrepareForIncrementalBackup(IncrementalBackupInfo *ib,
264 : : BackupState *backup_state)
265 : : {
266 : : MemoryContext oldcontext;
267 : : List *expectedTLEs;
268 : : List *all_wslist,
269 : 10 : *required_wslist = NIL;
270 : : ListCell *lc;
271 : : TimeLineHistoryEntry **tlep;
272 : : int num_wal_ranges;
273 : 10 : bool found_backup_start_tli = false;
274 : 10 : TimeLineID earliest_wal_range_tli = 0;
275 : 10 : XLogRecPtr earliest_wal_range_start_lsn = InvalidXLogRecPtr;
276 : 10 : TimeLineID latest_wal_range_tli = 0;
277 : :
278 [ - + ]: 10 : Assert(ib->buf.data == NULL);
279 : :
280 : : /* Switch to our memory context. */
281 : 10 : oldcontext = MemoryContextSwitchTo(ib->mcxt);
282 : :
283 : : /*
284 : : * A valid backup manifest must always contain at least one WAL range
285 : : * (usually exactly one, unless the backup spanned a timeline switch).
286 : : */
287 : 10 : num_wal_ranges = list_length(ib->manifest_wal_ranges);
288 [ - + ]: 10 : if (num_wal_ranges == 0)
816 rhaas@postgresql.org 289 [ # # ]:UBC 0 : ereport(ERROR,
290 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
291 : : errmsg("manifest contains no required WAL ranges")));
292 : :
293 : : /*
294 : : * Match up the TLIs that appear in the WAL ranges of the backup manifest
295 : : * with those that appear in this server's timeline history. We expect
296 : : * every backup_wal_range to match to a TimeLineHistoryEntry; if it does
297 : : * not, that's an error.
298 : : *
299 : : * This loop also decides which of the WAL ranges is the manifest is most
300 : : * ancient and which one is the newest, according to the timeline history
301 : : * of this server, and stores TLIs of those WAL ranges into
302 : : * earliest_wal_range_tli and latest_wal_range_tli. It also updates
303 : : * earliest_wal_range_start_lsn to the start LSN of the WAL range for
304 : : * earliest_wal_range_tli.
305 : : *
306 : : * Note that the return value of readTimeLineHistory puts the latest
307 : : * timeline at the beginning of the list, not the end. Hence, the earliest
308 : : * TLI is the one that occurs nearest the end of the list returned by
309 : : * readTimeLineHistory, and the latest TLI is the one that occurs closest
310 : : * to the beginning.
311 : : */
816 rhaas@postgresql.org 312 :CBC 10 : expectedTLEs = readTimeLineHistory(backup_state->starttli);
313 : 10 : tlep = palloc0(num_wal_ranges * sizeof(TimeLineHistoryEntry *));
12 alvherre@kurilemu.de 314 [ + + ]:GNC 20 : for (int i = 0; i < num_wal_ranges; ++i)
315 : : {
816 rhaas@postgresql.org 316 :CBC 10 : backup_wal_range *range = list_nth(ib->manifest_wal_ranges, i);
317 : 10 : bool saw_earliest_wal_range_tli = false;
318 : 10 : bool saw_latest_wal_range_tli = false;
319 : :
320 : : /* Search this server's history for this WAL range's TLI. */
321 [ + - + - : 11 : foreach(lc, expectedTLEs)
+ - ]
322 : : {
323 : 11 : TimeLineHistoryEntry *tle = lfirst(lc);
324 : :
325 [ + + ]: 11 : if (tle->tli == range->tli)
326 : : {
327 : 10 : tlep[i] = tle;
328 : 10 : break;
329 : : }
330 : :
331 [ - + ]: 1 : if (tle->tli == earliest_wal_range_tli)
816 rhaas@postgresql.org 332 :UBC 0 : saw_earliest_wal_range_tli = true;
816 rhaas@postgresql.org 333 [ - + ]:CBC 1 : if (tle->tli == latest_wal_range_tli)
816 rhaas@postgresql.org 334 :UBC 0 : saw_latest_wal_range_tli = true;
335 : : }
336 : :
337 : : /*
338 : : * An incremental backup can only be taken relative to a backup that
339 : : * represents a previous state of this server. If the backup requires
340 : : * WAL from a timeline that's not in our history, that definitely
341 : : * isn't the case.
342 : : */
816 rhaas@postgresql.org 343 [ - + ]:CBC 10 : if (tlep[i] == NULL)
816 rhaas@postgresql.org 344 [ # # ]:UBC 0 : ereport(ERROR,
345 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
346 : : errmsg("timeline %u found in manifest, but not in this server's history",
347 : : range->tli)));
348 : :
349 : : /*
350 : : * If we found this TLI in the server's history before encountering
351 : : * the latest TLI seen so far in the server's history, then this TLI
352 : : * is the latest one seen so far.
353 : : *
354 : : * If on the other hand we saw the earliest TLI seen so far before
355 : : * finding this TLI, this TLI is earlier than the earliest one seen so
356 : : * far. And if this is the first TLI for which we've searched, it's
357 : : * also the earliest one seen so far.
358 : : *
359 : : * On the first loop iteration, both things should necessarily be
360 : : * true.
361 : : */
816 rhaas@postgresql.org 362 [ + - ]:CBC 10 : if (!saw_latest_wal_range_tli)
363 : 10 : latest_wal_range_tli = range->tli;
364 [ - + - - ]: 10 : if (earliest_wal_range_tli == 0 || saw_earliest_wal_range_tli)
365 : : {
366 : 10 : earliest_wal_range_tli = range->tli;
367 : 10 : earliest_wal_range_start_lsn = range->start_lsn;
368 : : }
369 : : }
370 : :
371 : : /*
372 : : * Propagate information about the prior backup into the backup_label that
373 : : * will be generated for this backup.
374 : : */
375 : 10 : backup_state->istartpoint = earliest_wal_range_start_lsn;
376 : 10 : backup_state->istarttli = earliest_wal_range_tli;
377 : :
378 : : /*
379 : : * Sanity check start and end LSNs for the WAL ranges in the manifest.
380 : : *
381 : : * Commonly, there won't be any timeline switches during the prior backup
382 : : * at all, but if there are, they should happen at the same LSNs that this
383 : : * server switched timelines.
384 : : *
385 : : * Whether there are any timeline switches during the prior backup or not,
386 : : * the prior backup shouldn't require any WAL from a timeline prior to the
387 : : * start of that timeline. It also shouldn't require any WAL from later
388 : : * than the start of this backup.
389 : : *
390 : : * If any of these sanity checks fail, one possible explanation is that
391 : : * the user has generated WAL on the same timeline with the same LSNs more
392 : : * than once. For instance, if two standbys running on timeline 1 were
393 : : * both promoted and (due to a broken archiving setup) both selected new
394 : : * timeline ID 2, then it's possible that one of these checks might trip.
395 : : *
396 : : * Note that there are lots of ways for the user to do something very bad
397 : : * without tripping any of these checks, and they are not intended to be
398 : : * comprehensive. It's pretty hard to see how we could be certain of
399 : : * anything here. However, if there's a problem staring us right in the
400 : : * face, it's best to report it, so we do.
401 : : */
12 alvherre@kurilemu.de 402 [ + + ]:GNC 20 : for (int i = 0; i < num_wal_ranges; ++i)
403 : : {
816 rhaas@postgresql.org 404 :CBC 10 : backup_wal_range *range = list_nth(ib->manifest_wal_ranges, i);
405 : :
406 [ + - ]: 10 : if (range->tli == earliest_wal_range_tli)
407 : : {
408 [ - + ]: 10 : if (range->start_lsn < tlep[i]->begin)
816 rhaas@postgresql.org 409 [ # # ]:UBC 0 : ereport(ERROR,
410 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
411 : : errmsg("manifest requires WAL from initial timeline %u starting at %X/%08X, but that timeline begins at %X/%08X",
412 : : range->tli,
413 : : LSN_FORMAT_ARGS(range->start_lsn),
414 : : LSN_FORMAT_ARGS(tlep[i]->begin))));
415 : : }
416 : : else
417 : : {
418 [ # # ]: 0 : if (range->start_lsn != tlep[i]->begin)
419 [ # # ]: 0 : ereport(ERROR,
420 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
421 : : errmsg("manifest requires WAL from continuation timeline %u starting at %X/%08X, but that timeline begins at %X/%08X",
422 : : range->tli,
423 : : LSN_FORMAT_ARGS(range->start_lsn),
424 : : LSN_FORMAT_ARGS(tlep[i]->begin))));
425 : : }
426 : :
816 rhaas@postgresql.org 427 [ + - ]:CBC 10 : if (range->tli == latest_wal_range_tli)
428 : : {
429 [ - + ]: 10 : if (range->end_lsn > backup_state->startpoint)
816 rhaas@postgresql.org 430 [ # # ]:UBC 0 : ereport(ERROR,
431 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
432 : : errmsg("manifest requires WAL from final timeline %u ending at %X/%08X, but this backup starts at %X/%08X",
433 : : range->tli,
434 : : LSN_FORMAT_ARGS(range->end_lsn),
435 : : LSN_FORMAT_ARGS(backup_state->startpoint)),
436 : : errhint("This can happen for incremental backups on a standby if there was little activity since the previous backup.")));
437 : : }
438 : : else
439 : : {
440 [ # # ]: 0 : if (range->end_lsn != tlep[i]->end)
441 [ # # ]: 0 : ereport(ERROR,
442 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
443 : : errmsg("manifest requires WAL from non-final timeline %u ending at %X/%08X, but this server switched timelines at %X/%08X",
444 : : range->tli,
445 : : LSN_FORMAT_ARGS(range->end_lsn),
446 : : LSN_FORMAT_ARGS(tlep[i]->end))));
447 : : }
448 : :
449 : : }
450 : :
451 : : /*
452 : : * Wait for WAL summarization to catch up to the backup start LSN. This
453 : : * will throw an error if the WAL summarizer appears to be stuck. If WAL
454 : : * summarization gets disabled while we're waiting, this will return
455 : : * immediately, and we'll error out further down if the WAL summaries are
456 : : * incomplete.
457 : : */
597 rhaas@postgresql.org 458 :CBC 10 : WaitForWalSummarization(backup_state->startpoint);
459 : :
460 : : /*
461 : : * Retrieve a list of all WAL summaries on any timeline that overlap with
462 : : * the LSN range of interest. We could instead call GetWalSummaries() once
463 : : * per timeline in the loop that follows, but that would involve reading
464 : : * the directory multiple times. It should be mildly faster - and perhaps
465 : : * a bit safer - to do it just once.
466 : : */
816 467 : 10 : all_wslist = GetWalSummaries(0, earliest_wal_range_start_lsn,
468 : : backup_state->startpoint);
469 : :
470 : : /*
471 : : * We need WAL summaries for everything that happened during the prior
472 : : * backup and everything that happened afterward up until the point where
473 : : * the current backup started.
474 : : */
475 [ + - + - : 11 : foreach(lc, expectedTLEs)
+ - ]
476 : : {
477 : 11 : TimeLineHistoryEntry *tle = lfirst(lc);
478 : 11 : XLogRecPtr tli_start_lsn = tle->begin;
479 : 11 : XLogRecPtr tli_end_lsn = tle->end;
480 : 11 : XLogRecPtr tli_missing_lsn = InvalidXLogRecPtr;
481 : : List *tli_wslist;
482 : :
483 : : /*
484 : : * Working through the history of this server from the current
485 : : * timeline backwards, we skip everything until we find the timeline
486 : : * where this backup started. Most of the time, this means we won't
487 : : * skip anything at all, as it's unlikely that the timeline has
488 : : * changed since the beginning of the backup moments ago.
489 : : */
490 [ + + ]: 11 : if (tle->tli == backup_state->starttli)
491 : : {
492 : 10 : found_backup_start_tli = true;
493 : 10 : tli_end_lsn = backup_state->startpoint;
494 : : }
495 [ - + ]: 1 : else if (!found_backup_start_tli)
816 rhaas@postgresql.org 496 :UBC 0 : continue;
497 : :
498 : : /*
499 : : * Find the summaries that overlap the LSN range of interest for this
500 : : * timeline. If this is the earliest timeline involved, the range of
501 : : * interest begins with the start LSN of the prior backup; otherwise,
502 : : * it begins at the LSN at which this timeline came into existence. If
503 : : * this is the latest TLI involved, the range of interest ends at the
504 : : * start LSN of the current backup; otherwise, it ends at the point
505 : : * where we switched from this timeline to the next one.
506 : : */
816 rhaas@postgresql.org 507 [ + + ]:CBC 11 : if (tle->tli == earliest_wal_range_tli)
508 : 10 : tli_start_lsn = earliest_wal_range_start_lsn;
509 : 11 : tli_wslist = FilterWalSummaries(all_wslist, tle->tli,
510 : : tli_start_lsn, tli_end_lsn);
511 : :
512 : : /*
513 : : * There is no guarantee that the WAL summaries we found cover the
514 : : * entire range of LSNs for which summaries are required, or indeed
515 : : * that we found any WAL summaries at all. Check whether we have a
516 : : * problem of that sort.
517 : : */
518 [ - + ]: 11 : if (!WalSummariesAreComplete(tli_wslist, tli_start_lsn, tli_end_lsn,
519 : : &tli_missing_lsn))
520 : : {
129 alvherre@kurilemu.de 521 [ # # ]:UNC 0 : if (!XLogRecPtrIsValid(tli_missing_lsn))
816 rhaas@postgresql.org 522 [ # # ]:UBC 0 : ereport(ERROR,
523 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
524 : : errmsg("WAL summaries are required on timeline %u from %X/%08X to %X/%08X, but no summaries for that timeline and LSN range exist",
525 : : tle->tli,
526 : : LSN_FORMAT_ARGS(tli_start_lsn),
527 : : LSN_FORMAT_ARGS(tli_end_lsn))));
528 : : else
529 [ # # ]: 0 : ereport(ERROR,
530 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
531 : : errmsg("WAL summaries are required on timeline %u from %X/%08X to %X/%08X, but the summaries for that timeline and LSN range are incomplete",
532 : : tle->tli,
533 : : LSN_FORMAT_ARGS(tli_start_lsn),
534 : : LSN_FORMAT_ARGS(tli_end_lsn)),
535 : : errdetail("The first unsummarized LSN in this range is %X/%08X.",
536 : : LSN_FORMAT_ARGS(tli_missing_lsn))));
537 : : }
538 : :
539 : : /*
540 : : * Remember that we need to read these summaries.
541 : : *
542 : : * Technically, it's possible that this could read more files than
543 : : * required, since tli_wslist in theory could contain redundant
544 : : * summaries. For instance, if we have a summary from 0/10000000 to
545 : : * 0/20000000 and also one from 0/00000000 to 0/30000000, then the
546 : : * latter subsumes the former and the former could be ignored.
547 : : *
548 : : * We ignore this possibility because the WAL summarizer only tries to
549 : : * generate summaries that do not overlap. If somehow they exist,
550 : : * we'll do a bit of extra work but the results should still be
551 : : * correct.
552 : : */
816 rhaas@postgresql.org 553 :CBC 11 : required_wslist = list_concat(required_wslist, tli_wslist);
554 : :
555 : : /*
556 : : * Timelines earlier than the one in which the prior backup began are
557 : : * not relevant.
558 : : */
559 [ + + ]: 11 : if (tle->tli == earliest_wal_range_tli)
560 : 10 : break;
561 : : }
562 : :
563 : : /*
564 : : * Read all of the required block reference table files and merge all of
565 : : * the data into a single in-memory block reference table.
566 : : *
567 : : * See the comments for struct IncrementalBackupInfo for some thoughts on
568 : : * memory usage.
569 : : */
570 : 10 : ib->brtab = CreateEmptyBlockRefTable();
571 [ + - + + : 28 : foreach(lc, required_wslist)
+ + ]
572 : : {
573 : 18 : WalSummaryFile *ws = lfirst(lc);
574 : : WalSummaryIO wsio;
575 : : BlockRefTableReader *reader;
576 : : RelFileLocator rlocator;
577 : : ForkNumber forknum;
578 : : BlockNumber limit_block;
579 : : BlockNumber blocks[BLOCKS_PER_READ];
580 : :
581 : 18 : wsio.file = OpenWalSummaryFile(ws, false);
582 : 18 : wsio.filepos = 0;
583 [ + + ]: 18 : ereport(DEBUG1,
584 : : (errmsg_internal("reading WAL summary file \"%s\"",
585 : : FilePathName(wsio.file))));
586 : 18 : reader = CreateBlockRefTableReader(ReadWalSummary, &wsio,
587 : : FilePathName(wsio.file),
588 : : ReportWalSummaryError, NULL);
589 [ + + ]: 372 : while (BlockRefTableReaderNextRelation(reader, &rlocator, &forknum,
590 : : &limit_block))
591 : : {
592 : 354 : BlockRefTableSetLimitBlock(ib->brtab, &rlocator,
593 : : forknum, limit_block);
594 : :
595 : : while (1)
596 : 256 : {
597 : : unsigned int nblocks;
598 : :
599 : 610 : nblocks = BlockRefTableReaderGetBlocks(reader, blocks,
600 : : BLOCKS_PER_READ);
601 [ + + ]: 610 : if (nblocks == 0)
602 : 354 : break;
603 : :
12 alvherre@kurilemu.de 604 [ + + ]:GNC 1188 : for (unsigned int i = 0; i < nblocks; ++i)
816 rhaas@postgresql.org 605 :CBC 932 : BlockRefTableMarkBlockModified(ib->brtab, &rlocator,
606 : : forknum, blocks[i]);
607 : : }
608 : : }
609 : 18 : DestroyBlockRefTableReader(reader);
610 : 18 : FileClose(wsio.file);
611 : : }
612 : :
613 : : /* Switch back to previous memory context. */
614 : 10 : MemoryContextSwitchTo(oldcontext);
615 : 10 : }
616 : :
617 : : /*
618 : : * Get the pathname that should be used when a file is sent incrementally.
619 : : *
620 : : * The result is a palloc'd string.
621 : : */
622 : : char *
623 : 1605 : GetIncrementalFilePath(Oid dboid, Oid spcoid, RelFileNumber relfilenumber,
624 : : ForkNumber forknum, unsigned segno)
625 : : {
626 : : RelPathStr path;
627 : : char *lastslash;
628 : : char *ipath;
629 : :
742 heikki.linnakangas@i 630 : 1605 : path = GetRelationPath(dboid, spcoid, relfilenumber, INVALID_PROC_NUMBER,
631 : : forknum);
632 : :
383 andres@anarazel.de 633 : 1605 : lastslash = strrchr(path.str, '/');
816 rhaas@postgresql.org 634 [ - + ]: 1605 : Assert(lastslash != NULL);
635 : 1605 : *lastslash = '\0';
636 : :
637 [ - + ]: 1605 : if (segno > 0)
383 andres@anarazel.de 638 :UBC 0 : ipath = psprintf("%s/INCREMENTAL.%s.%u", path.str, lastslash + 1, segno);
639 : : else
383 andres@anarazel.de 640 :CBC 1605 : ipath = psprintf("%s/INCREMENTAL.%s", path.str, lastslash + 1);
641 : :
816 rhaas@postgresql.org 642 : 1605 : return ipath;
643 : : }
644 : :
645 : : /*
646 : : * How should we back up a particular file as part of an incremental backup?
647 : : *
648 : : * If the return value is BACK_UP_FILE_FULLY, caller should back up the whole
649 : : * file just as if this were not an incremental backup. The contents of the
650 : : * relative_block_numbers array are unspecified in this case.
651 : : *
652 : : * If the return value is BACK_UP_FILE_INCREMENTALLY, caller should include
653 : : * an incremental file in the backup instead of the entire file. On return,
654 : : * *num_blocks_required will be set to the number of blocks that need to be
655 : : * sent, and the actual block numbers will have been stored in
656 : : * relative_block_numbers, which should be an array of at least RELSEG_SIZE.
657 : : * In addition, *truncation_block_length will be set to the value that should
658 : : * be included in the incremental file.
659 : : */
660 : : FileBackupMethod
661 : 10145 : GetFileBackupMethod(IncrementalBackupInfo *ib, const char *path,
662 : : Oid dboid, Oid spcoid,
663 : : RelFileNumber relfilenumber, ForkNumber forknum,
664 : : unsigned segno, size_t size,
665 : : unsigned *num_blocks_required,
666 : : BlockNumber *relative_block_numbers,
667 : : unsigned *truncation_block_length)
668 : : {
669 : : BlockNumber limit_block;
670 : : BlockNumber start_blkno;
671 : : BlockNumber stop_blkno;
672 : : RelFileLocator rlocator;
673 : : BlockRefTableEntry *brtentry;
674 : : unsigned i;
675 : : unsigned nblocks;
676 : :
677 : : /* Should only be called after PrepareForIncrementalBackup. */
678 [ - + ]: 10145 : Assert(ib->buf.data == NULL);
679 : :
680 : : /*
681 : : * dboid could be InvalidOid if shared rel, but spcoid and relfilenumber
682 : : * should have legal values.
683 : : */
684 [ - + ]: 10145 : Assert(OidIsValid(spcoid));
685 [ - + ]: 10145 : Assert(RelFileNumberIsValid(relfilenumber));
686 : :
687 : : /*
688 : : * If the file size is too large or not a multiple of BLCKSZ, then
689 : : * something weird is happening, so give up and send the whole file.
690 : : */
691 [ + - - + ]: 10145 : if ((size % BLCKSZ) != 0 || size / BLCKSZ > RELSEG_SIZE)
816 rhaas@postgresql.org 692 :UBC 0 : return BACK_UP_FILE_FULLY;
693 : :
694 : : /*
695 : : * The free-space map fork is not properly WAL-logged, so we need to
696 : : * backup the entire file every time.
697 : : */
816 rhaas@postgresql.org 698 [ + + ]:CBC 10145 : if (forknum == FSM_FORKNUM)
699 : 1238 : return BACK_UP_FILE_FULLY;
700 : :
701 : : /*
702 : : * If this file was not part of the prior backup, back it up fully.
703 : : *
704 : : * If this file was created after the prior backup and before the start of
705 : : * the current backup, then the WAL summary information will tell us to
706 : : * back up the whole file. However, if this file was created after the
707 : : * start of the current backup, then the WAL summary won't know anything
708 : : * about it. Without this logic, we would erroneously conclude that it was
709 : : * OK to send it incrementally.
710 : : *
711 : : * Note that the file could have existed at the time of the prior backup,
712 : : * gotten deleted, and then a new file with the same name could have been
713 : : * created. In that case, this logic won't prevent the file from being
714 : : * backed up incrementally. But, if the deletion happened before the start
715 : : * of the current backup, the limit block will be 0, inducing a full
716 : : * backup. If the deletion happened after the start of the current backup,
717 : : * reconstruction will erroneously combine blocks from the current
718 : : * lifespan of the file with blocks from the previous lifespan -- but in
719 : : * this type of case, WAL replay to reach backup consistency should remove
720 : : * and recreate the file anyway, so the initial bogus contents should not
721 : : * matter.
722 : : */
723 [ + + ]: 8907 : if (backup_file_lookup(ib->manifest_files, path) == NULL)
724 : : {
725 : : char *ipath;
726 : :
727 : 1605 : ipath = GetIncrementalFilePath(dboid, spcoid, relfilenumber,
728 : : forknum, segno);
729 [ + + ]: 1605 : if (backup_file_lookup(ib->manifest_files, ipath) == NULL)
730 : 274 : return BACK_UP_FILE_FULLY;
731 : : }
732 : :
733 : : /*
734 : : * Look up the special block reference table entry for the database as a
735 : : * whole.
736 : : */
737 : 8633 : rlocator.spcOid = spcoid;
738 : 8633 : rlocator.dbOid = dboid;
741 739 : 8633 : rlocator.relNumber = 0;
740 [ + + ]: 8633 : if (BlockRefTableGetEntry(ib->brtab, &rlocator, MAIN_FORKNUM,
741 : : &limit_block) != NULL)
742 : : {
743 : : /*
744 : : * According to the WAL summary, this database OID/tablespace OID
745 : : * pairing has been created since the previous backup. So, everything
746 : : * in it must be backed up fully.
747 : : */
748 : 261 : return BACK_UP_FILE_FULLY;
749 : : }
750 : :
751 : : /* Look up the block reference table entry for this relfilenode. */
816 752 : 8372 : rlocator.relNumber = relfilenumber;
753 : 8372 : brtentry = BlockRefTableGetEntry(ib->brtab, &rlocator, forknum,
754 : : &limit_block);
755 : :
756 : : /*
757 : : * If there is no entry, then there have been no WAL-logged changes to the
758 : : * relation since the predecessor backup was taken, so we can back it up
759 : : * incrementally and need not include any modified blocks.
760 : : *
761 : : * However, if the file is zero-length, we should do a full backup,
762 : : * because an incremental file is always more than zero length, and it's
763 : : * silly to take an incremental backup when a full backup would be
764 : : * smaller.
765 : : */
766 [ + + ]: 8372 : if (brtentry == NULL)
767 : : {
768 [ + + ]: 8335 : if (size == 0)
769 : 1700 : return BACK_UP_FILE_FULLY;
770 : 6635 : *num_blocks_required = 0;
771 : 6635 : *truncation_block_length = size / BLCKSZ;
772 : 6635 : return BACK_UP_FILE_INCREMENTALLY;
773 : : }
774 : :
775 : : /*
776 : : * If the limit_block is less than or equal to the point where this
777 : : * segment starts, send the whole file.
778 : : */
779 [ - + ]: 37 : if (limit_block <= segno * RELSEG_SIZE)
816 rhaas@postgresql.org 780 :UBC 0 : return BACK_UP_FILE_FULLY;
781 : :
782 : : /*
783 : : * Get relevant entries from the block reference table entry.
784 : : *
785 : : * We shouldn't overflow computing the start or stop block numbers, but if
786 : : * it manages to happen somehow, detect it and throw an error.
787 : : */
816 rhaas@postgresql.org 788 :CBC 37 : start_blkno = segno * RELSEG_SIZE;
789 : 37 : stop_blkno = start_blkno + (size / BLCKSZ);
790 [ + - - + ]: 37 : if (start_blkno / RELSEG_SIZE != segno || stop_blkno < start_blkno)
816 rhaas@postgresql.org 791 [ # # ]:UBC 0 : ereport(ERROR,
792 : : errcode(ERRCODE_INTERNAL_ERROR),
793 : : errmsg_internal("overflow computing block number bounds for segment %u with size %zu",
794 : : segno, size));
795 : :
796 : : /*
797 : : * This will write *absolute* block numbers into the output array, but
798 : : * we'll transpose them below.
799 : : */
816 rhaas@postgresql.org 800 :CBC 37 : nblocks = BlockRefTableEntryGetBlocks(brtentry, start_blkno, stop_blkno,
801 : : relative_block_numbers, RELSEG_SIZE);
802 [ - + ]: 37 : Assert(nblocks <= RELSEG_SIZE);
803 : :
804 : : /*
805 : : * If we're going to have to send nearly all of the blocks, then just send
806 : : * the whole file, because that won't require much extra storage or
807 : : * transfer and will speed up and simplify backup restoration. It's not
808 : : * clear what threshold is most appropriate here and perhaps it ought to
809 : : * be configurable, but for now we're just going to say that if we'd need
810 : : * to send 90% of the blocks anyway, give up and send the whole file.
811 : : *
812 : : * NB: If you change the threshold here, at least make sure to back up the
813 : : * file fully when every single block must be sent, because there's
814 : : * nothing good about sending an incremental file in that case.
815 : : */
816 [ + + ]: 37 : if (nblocks * BLCKSZ > size * 0.9)
817 : 10 : return BACK_UP_FILE_FULLY;
818 : :
819 : : /*
820 : : * Looks like we can send an incremental file, so sort the block numbers
821 : : * and then transpose them from absolute block numbers to relative block
822 : : * numbers if necessary.
823 : : *
824 : : * NB: If the block reference table was using the bitmap representation
825 : : * for a given chunk, the block numbers in that chunk will already be
826 : : * sorted, but when the array-of-offsets representation is used, we can
827 : : * receive block numbers here out of order.
828 : : */
703 tmunro@postgresql.or 829 : 27 : qsort(relative_block_numbers, nblocks, sizeof(BlockNumber),
830 : : compare_block_numbers);
831 [ - + ]: 27 : if (start_blkno != 0)
832 : : {
703 tmunro@postgresql.or 833 [ # # ]:UBC 0 : for (i = 0; i < nblocks; ++i)
834 : 0 : relative_block_numbers[i] -= start_blkno;
835 : : }
816 rhaas@postgresql.org 836 :CBC 27 : *num_blocks_required = nblocks;
837 : :
838 : : /*
839 : : * The truncation block length is the minimum length of the reconstructed
840 : : * file. Any block numbers below this threshold that are not present in
841 : : * the backup need to be fetched from the prior backup. At or above this
842 : : * threshold, blocks should only be included in the result if they are
843 : : * present in the backup. (This may require inserting zero blocks if the
844 : : * blocks included in the backup are non-consecutive.)
845 : : */
846 : 27 : *truncation_block_length = size / BLCKSZ;
847 [ + + ]: 27 : if (BlockNumberIsValid(limit_block))
848 : : {
849 : 1 : unsigned relative_limit = limit_block - segno * RELSEG_SIZE;
850 : :
851 : : /*
852 : : * We can't set a truncation_block_length in excess of the limit block
853 : : * number (relativized to the current segment). To do so would be to
854 : : * treat blocks from older backups as valid current contents even if
855 : : * they were subsequently truncated away.
856 : : */
857 [ - + ]: 1 : if (*truncation_block_length < relative_limit)
816 rhaas@postgresql.org 858 :UBC 0 : *truncation_block_length = relative_limit;
859 : :
860 : : /*
861 : : * We also can't set a truncation_block_length in excess of the
862 : : * segment size, since the reconstructed file can't be larger than
863 : : * that.
864 : : */
55 rhaas@postgresql.org 865 [ - + ]:CBC 1 : if (*truncation_block_length > RELSEG_SIZE)
55 rhaas@postgresql.org 866 :UBC 0 : *truncation_block_length = RELSEG_SIZE;
867 : : }
868 : :
869 : : /* Send it incrementally. */
816 rhaas@postgresql.org 870 :CBC 27 : return BACK_UP_FILE_INCREMENTALLY;
871 : : }
872 : :
873 : : /*
874 : : * Compute the size for a header of an incremental file containing a given
875 : : * number of blocks. The header is rounded to a multiple of BLCKSZ, but
876 : : * only if the file will store some block data.
877 : : */
878 : : size_t
709 tomas.vondra@postgre 879 : 6662 : GetIncrementalHeaderSize(unsigned num_blocks_required)
880 : : {
881 : : size_t result;
882 : :
883 : : /* Make sure we're not going to overflow. */
884 [ - + ]: 6662 : Assert(num_blocks_required <= RELSEG_SIZE);
885 : :
886 : : /*
887 : : * Three four byte quantities (magic number, truncation block length,
888 : : * block count) followed by block numbers.
889 : : */
890 : 6662 : result = 3 * sizeof(uint32) + (sizeof(BlockNumber) * num_blocks_required);
891 : :
892 : : /*
893 : : * Round the header size to a multiple of BLCKSZ - when not a multiple of
894 : : * BLCKSZ, add the missing fraction of a block. But do this only if the
895 : : * file will store data for some blocks, otherwise keep it small.
896 : : */
897 [ + + + - ]: 6662 : if ((num_blocks_required > 0) && (result % BLCKSZ != 0))
898 : 26 : result += BLCKSZ - (result % BLCKSZ);
899 : :
900 : 6662 : return result;
901 : : }
902 : :
903 : : /*
904 : : * Compute the size for an incremental file containing a given number of blocks.
905 : : */
906 : : size_t
816 rhaas@postgresql.org 907 : 6662 : GetIncrementalFileSize(unsigned num_blocks_required)
908 : : {
909 : : size_t result;
910 : :
911 : : /* Make sure we're not going to overflow. */
912 [ - + ]: 6662 : Assert(num_blocks_required <= RELSEG_SIZE);
913 : :
914 : : /*
915 : : * Header with three four byte quantities (magic number, truncation block
916 : : * length, block count) followed by block numbers, rounded to a multiple
917 : : * of BLCKSZ (for files with block data), followed by block contents.
918 : : */
709 tomas.vondra@postgre 919 : 6662 : result = GetIncrementalHeaderSize(num_blocks_required);
920 : 6662 : result += BLCKSZ * num_blocks_required;
921 : :
816 rhaas@postgresql.org 922 : 6662 : return result;
923 : : }
924 : :
925 : : /*
926 : : * Helper function for filemap hash table.
927 : : */
928 : : static uint32
929 : 21152 : hash_string_pointer(const char *s)
930 : : {
48 peter@eisentraut.org 931 :GNC 21152 : const unsigned char *ss = (const unsigned char *) s;
932 : :
816 rhaas@postgresql.org 933 :CBC 21152 : return hash_bytes(ss, strlen(s));
934 : : }
935 : :
936 : : /*
937 : : * This callback to validate the manifest version for incremental backup.
938 : : */
939 : : static void
732 940 : 11 : manifest_process_version(JsonManifestParseContext *context,
941 : : int manifest_version)
942 : : {
943 : : /* Incremental backups don't work with manifest version 1 */
944 [ - + ]: 11 : if (manifest_version == 1)
732 rhaas@postgresql.org 945 :UBC 0 : context->error_cb(context,
946 : : "backup manifest version 1 does not support incremental backup");
732 rhaas@postgresql.org 947 :CBC 11 : }
948 : :
949 : : /*
950 : : * This callback to validate the manifest system identifier against the current
951 : : * database server.
952 : : */
953 : : static void
954 : 11 : manifest_process_system_identifier(JsonManifestParseContext *context,
955 : : uint64 manifest_system_identifier)
956 : : {
957 : : uint64 system_identifier;
958 : :
959 : : /* Get system identifier of current system */
960 : 11 : system_identifier = GetSystemIdentifier();
961 : :
962 [ + + ]: 11 : if (manifest_system_identifier != system_identifier)
963 : 1 : context->error_cb(context,
964 : : "system identifier in backup manifest is %" PRIu64 ", but database system identifier is %" PRIu64,
965 : : manifest_system_identifier,
966 : : system_identifier);
967 : 10 : }
968 : :
969 : : /*
970 : : * This callback is invoked for each file mentioned in the backup manifest.
971 : : *
972 : : * We store the path to each file and the size of each file for sanity-checking
973 : : * purposes. For further details, see comments for IncrementalBackupInfo.
974 : : */
975 : : static void
816 976 : 10328 : manifest_process_file(JsonManifestParseContext *context,
977 : : const char *pathname, uint64 size,
978 : : pg_checksum_type checksum_type,
979 : : int checksum_length,
980 : : uint8 *checksum_payload)
981 : : {
982 : 10328 : IncrementalBackupInfo *ib = context->private_data;
983 : : backup_file_entry *entry;
984 : : bool found;
985 : :
986 : 10328 : entry = backup_file_insert(ib->manifest_files, pathname, &found);
987 [ + - ]: 10328 : if (!found)
988 : : {
989 : 10328 : entry->path = MemoryContextStrdup(ib->manifest_files->ctx,
990 : : pathname);
991 : 10328 : entry->size = size;
992 : : }
993 : 10328 : }
994 : :
995 : : /*
996 : : * This callback is invoked for each WAL range mentioned in the backup
997 : : * manifest.
998 : : *
999 : : * We're just interested in learning the oldest LSN and the corresponding TLI
1000 : : * that appear in any WAL range.
1001 : : */
1002 : : static void
1003 : 10 : manifest_process_wal_range(JsonManifestParseContext *context,
1004 : : TimeLineID tli, XLogRecPtr start_lsn,
1005 : : XLogRecPtr end_lsn)
1006 : : {
1007 : 10 : IncrementalBackupInfo *ib = context->private_data;
95 michael@paquier.xyz 1008 :GNC 10 : backup_wal_range *range = palloc_object(backup_wal_range);
1009 : :
816 rhaas@postgresql.org 1010 :CBC 10 : range->tli = tli;
1011 : 10 : range->start_lsn = start_lsn;
1012 : 10 : range->end_lsn = end_lsn;
1013 : 10 : ib->manifest_wal_ranges = lappend(ib->manifest_wal_ranges, range);
1014 : 10 : }
1015 : :
1016 : : /*
1017 : : * This callback is invoked if an error occurs while parsing the backup
1018 : : * manifest.
1019 : : */
1020 : : static void
1021 : 1 : manifest_report_error(JsonManifestParseContext *context, const char *fmt,...)
1022 : : {
1023 : : StringInfoData errbuf;
1024 : :
1025 : 1 : initStringInfo(&errbuf);
1026 : :
1027 : : for (;;)
816 rhaas@postgresql.org 1028 :UBC 0 : {
1029 : : va_list ap;
1030 : : int needed;
1031 : :
816 rhaas@postgresql.org 1032 :CBC 1 : va_start(ap, fmt);
1033 : 1 : needed = appendStringInfoVA(&errbuf, fmt, ap);
1034 : 1 : va_end(ap);
1035 [ + - ]: 1 : if (needed == 0)
1036 : 1 : break;
816 rhaas@postgresql.org 1037 :UBC 0 : enlargeStringInfo(&errbuf, needed);
1038 : : }
1039 : :
816 rhaas@postgresql.org 1040 [ + - ]:CBC 1 : ereport(ERROR,
1041 : : errmsg_internal("%s", errbuf.data));
1042 : : }
1043 : :
1044 : : /*
1045 : : * Quicksort comparator for block numbers.
1046 : : */
1047 : : static int
1048 : 15 : compare_block_numbers(const void *a, const void *b)
1049 : : {
48 peter@eisentraut.org 1050 :GNC 15 : BlockNumber aa = *(const BlockNumber *) a;
1051 : 15 : BlockNumber bb = *(const BlockNumber *) b;
1052 : :
758 nathan@postgresql.or 1053 :CBC 15 : return pg_cmp_u32(aa, bb);
1054 : : }
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