Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * reinit.c
4 : * Reinitialization of unlogged relations
5 : *
6 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : * IDENTIFICATION
10 : * src/backend/storage/file/reinit.c
11 : *
12 : *-------------------------------------------------------------------------
13 : */
14 :
15 : #include "postgres.h"
16 :
17 : #include <unistd.h>
18 :
19 : #include "common/relpath.h"
20 : #include "postmaster/startup.h"
21 : #include "storage/copydir.h"
22 : #include "storage/fd.h"
23 : #include "storage/reinit.h"
24 : #include "utils/hsearch.h"
25 : #include "utils/memutils.h"
26 :
27 : static void ResetUnloggedRelationsInTablespaceDir(const char *tsdirname,
28 : int op);
29 : static void ResetUnloggedRelationsInDbspaceDir(const char *dbspacedirname,
30 : int op);
31 :
32 : typedef struct
33 : {
34 : RelFileNumber relnumber; /* hash key */
35 : } unlogged_relation_entry;
36 :
37 : /*
38 : * Reset unlogged relations from before the last restart.
39 : *
40 : * If op includes UNLOGGED_RELATION_CLEANUP, we remove all forks of any
41 : * relation with an "init" fork, except for the "init" fork itself.
42 : *
43 : * If op includes UNLOGGED_RELATION_INIT, we copy the "init" fork to the main
44 : * fork.
45 : */
46 : void
47 732 : ResetUnloggedRelations(int op)
48 : {
49 : char temp_path[MAXPGPATH + sizeof(PG_TBLSPC_DIR) + sizeof(TABLESPACE_VERSION_DIRECTORY)];
50 : DIR *spc_dir;
51 : struct dirent *spc_de;
52 : MemoryContext tmpctx,
53 : oldctx;
54 :
55 : /* Log it. */
56 732 : elog(DEBUG1, "resetting unlogged relations: cleanup %d init %d",
57 : (op & UNLOGGED_RELATION_CLEANUP) != 0,
58 : (op & UNLOGGED_RELATION_INIT) != 0);
59 :
60 : /*
61 : * Just to be sure we don't leak any memory, let's create a temporary
62 : * memory context for this operation.
63 : */
64 732 : tmpctx = AllocSetContextCreate(CurrentMemoryContext,
65 : "ResetUnloggedRelations",
66 : ALLOCSET_DEFAULT_SIZES);
67 732 : oldctx = MemoryContextSwitchTo(tmpctx);
68 :
69 : /* Prepare to report progress resetting unlogged relations. */
70 732 : begin_startup_progress_phase();
71 :
72 : /*
73 : * First process unlogged files in pg_default ($PGDATA/base)
74 : */
75 732 : ResetUnloggedRelationsInTablespaceDir("base", op);
76 :
77 : /*
78 : * Cycle through directories for all non-default tablespaces.
79 : */
80 732 : spc_dir = AllocateDir(PG_TBLSPC_DIR);
81 :
82 2370 : while ((spc_de = ReadDir(spc_dir, PG_TBLSPC_DIR)) != NULL)
83 : {
84 1638 : if (strcmp(spc_de->d_name, ".") == 0 ||
85 906 : strcmp(spc_de->d_name, "..") == 0)
86 1464 : continue;
87 :
88 174 : snprintf(temp_path, sizeof(temp_path), "%s/%s/%s",
89 174 : PG_TBLSPC_DIR, spc_de->d_name, TABLESPACE_VERSION_DIRECTORY);
90 174 : ResetUnloggedRelationsInTablespaceDir(temp_path, op);
91 : }
92 :
93 732 : FreeDir(spc_dir);
94 :
95 : /*
96 : * Restore memory context.
97 : */
98 732 : MemoryContextSwitchTo(oldctx);
99 732 : MemoryContextDelete(tmpctx);
100 732 : }
101 :
102 : /*
103 : * Process one tablespace directory for ResetUnloggedRelations
104 : */
105 : static void
106 906 : ResetUnloggedRelationsInTablespaceDir(const char *tsdirname, int op)
107 : {
108 : DIR *ts_dir;
109 : struct dirent *de;
110 : char dbspace_path[MAXPGPATH * 2];
111 :
112 906 : ts_dir = AllocateDir(tsdirname);
113 :
114 : /*
115 : * If we get ENOENT on a tablespace directory, log it and return. This
116 : * can happen if a previous DROP TABLESPACE crashed between removing the
117 : * tablespace directory and removing the symlink in pg_tblspc. We don't
118 : * really want to prevent database startup in that scenario, so let it
119 : * pass instead. Any other type of error will be reported by ReadDir
120 : * (causing a startup failure).
121 : */
122 906 : if (ts_dir == NULL && errno == ENOENT)
123 : {
124 0 : ereport(LOG,
125 : (errcode_for_file_access(),
126 : errmsg("could not open directory \"%s\": %m",
127 : tsdirname)));
128 0 : return;
129 : }
130 :
131 5368 : while ((de = ReadDir(ts_dir, tsdirname)) != NULL)
132 : {
133 : /*
134 : * We're only interested in the per-database directories, which have
135 : * numeric names. Note that this code will also (properly) ignore "."
136 : * and "..".
137 : */
138 4462 : if (strspn(de->d_name, "0123456789") != strlen(de->d_name))
139 1942 : continue;
140 :
141 2520 : snprintf(dbspace_path, sizeof(dbspace_path), "%s/%s",
142 2520 : tsdirname, de->d_name);
143 :
144 2520 : if (op & UNLOGGED_RELATION_INIT)
145 1054 : ereport_startup_progress("resetting unlogged relations (init), elapsed time: %ld.%02d s, current path: %s",
146 : dbspace_path);
147 1466 : else if (op & UNLOGGED_RELATION_CLEANUP)
148 1466 : ereport_startup_progress("resetting unlogged relations (cleanup), elapsed time: %ld.%02d s, current path: %s",
149 : dbspace_path);
150 :
151 2520 : ResetUnloggedRelationsInDbspaceDir(dbspace_path, op);
152 : }
153 :
154 906 : FreeDir(ts_dir);
155 : }
156 :
157 : /*
158 : * Process one per-dbspace directory for ResetUnloggedRelations
159 : */
160 : static void
161 2520 : ResetUnloggedRelationsInDbspaceDir(const char *dbspacedirname, int op)
162 : {
163 : DIR *dbspace_dir;
164 : struct dirent *de;
165 : char rm_path[MAXPGPATH * 2];
166 :
167 : /* Caller must specify at least one operation. */
168 : Assert((op & (UNLOGGED_RELATION_CLEANUP | UNLOGGED_RELATION_INIT)) != 0);
169 :
170 : /*
171 : * Cleanup is a two-pass operation. First, we go through and identify all
172 : * the files with init forks. Then, we go through again and nuke
173 : * everything with the same OID except the init fork.
174 : */
175 2520 : if ((op & UNLOGGED_RELATION_CLEANUP) != 0)
176 : {
177 : HTAB *hash;
178 : HASHCTL ctl;
179 :
180 : /*
181 : * It's possible that someone could create a ton of unlogged relations
182 : * in the same database & tablespace, so we'd better use a hash table
183 : * rather than an array or linked list to keep track of which files
184 : * need to be reset. Otherwise, this cleanup operation would be
185 : * O(n^2).
186 : */
187 1466 : ctl.keysize = sizeof(Oid);
188 1466 : ctl.entrysize = sizeof(unlogged_relation_entry);
189 1466 : ctl.hcxt = CurrentMemoryContext;
190 1466 : hash = hash_create("unlogged relation OIDs", 32, &ctl,
191 : HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
192 :
193 : /* Scan the directory. */
194 1466 : dbspace_dir = AllocateDir(dbspacedirname);
195 421488 : while ((de = ReadDir(dbspace_dir, dbspacedirname)) != NULL)
196 : {
197 : ForkNumber forkNum;
198 : unsigned segno;
199 : unlogged_relation_entry ent;
200 :
201 : /* Skip anything that doesn't look like a relation data file. */
202 420022 : if (!parse_filename_for_nontemp_relation(de->d_name,
203 : &ent.relnumber,
204 : &forkNum, &segno))
205 420006 : continue;
206 :
207 : /* Also skip it unless this is the init fork. */
208 414330 : if (forkNum != INIT_FORKNUM)
209 414314 : continue;
210 :
211 : /*
212 : * Put the RelFileNumber into the hash table, if it isn't already.
213 : */
214 16 : (void) hash_search(hash, &ent, HASH_ENTER, NULL);
215 : }
216 :
217 : /* Done with the first pass. */
218 1466 : FreeDir(dbspace_dir);
219 :
220 : /*
221 : * If we didn't find any init forks, there's no point in continuing;
222 : * we can bail out now.
223 : */
224 1466 : if (hash_get_num_entries(hash) == 0)
225 : {
226 1458 : hash_destroy(hash);
227 1458 : return;
228 : }
229 :
230 : /*
231 : * Now, make a second pass and remove anything that matches.
232 : */
233 8 : dbspace_dir = AllocateDir(dbspacedirname);
234 1874 : while ((de = ReadDir(dbspace_dir, dbspacedirname)) != NULL)
235 : {
236 : ForkNumber forkNum;
237 : unsigned segno;
238 : unlogged_relation_entry ent;
239 :
240 : /* Skip anything that doesn't look like a relation data file. */
241 1866 : if (!parse_filename_for_nontemp_relation(de->d_name,
242 : &ent.relnumber,
243 : &forkNum, &segno))
244 44 : continue;
245 :
246 : /* We never remove the init fork. */
247 1838 : if (forkNum == INIT_FORKNUM)
248 16 : continue;
249 :
250 : /*
251 : * See whether the OID portion of the name shows up in the hash
252 : * table. If so, nuke it!
253 : */
254 1822 : if (hash_search(hash, &ent, HASH_FIND, NULL))
255 : {
256 14 : snprintf(rm_path, sizeof(rm_path), "%s/%s",
257 14 : dbspacedirname, de->d_name);
258 14 : if (unlink(rm_path) < 0)
259 0 : ereport(ERROR,
260 : (errcode_for_file_access(),
261 : errmsg("could not remove file \"%s\": %m",
262 : rm_path)));
263 : else
264 14 : elog(DEBUG2, "unlinked file \"%s\"", rm_path);
265 : }
266 : }
267 :
268 : /* Cleanup is complete. */
269 8 : FreeDir(dbspace_dir);
270 8 : hash_destroy(hash);
271 : }
272 :
273 : /*
274 : * Initialization happens after cleanup is complete: we copy each init
275 : * fork file to the corresponding main fork file. Note that if we are
276 : * asked to do both cleanup and init, we may never get here: if the
277 : * cleanup code determines that there are no init forks in this dbspace,
278 : * it will return before we get to this point.
279 : */
280 1062 : if ((op & UNLOGGED_RELATION_INIT) != 0)
281 : {
282 : /* Scan the directory. */
283 1054 : dbspace_dir = AllocateDir(dbspacedirname);
284 296450 : while ((de = ReadDir(dbspace_dir, dbspacedirname)) != NULL)
285 : {
286 : ForkNumber forkNum;
287 : RelFileNumber relNumber;
288 : unsigned segno;
289 : char srcpath[MAXPGPATH * 2];
290 : char dstpath[MAXPGPATH];
291 :
292 : /* Skip anything that doesn't look like a relation data file. */
293 295396 : if (!parse_filename_for_nontemp_relation(de->d_name, &relNumber,
294 : &forkNum, &segno))
295 295382 : continue;
296 :
297 : /* Also skip it unless this is the init fork. */
298 291306 : if (forkNum != INIT_FORKNUM)
299 291292 : continue;
300 :
301 : /* Construct source pathname. */
302 14 : snprintf(srcpath, sizeof(srcpath), "%s/%s",
303 14 : dbspacedirname, de->d_name);
304 :
305 : /* Construct destination pathname. */
306 14 : if (segno == 0)
307 14 : snprintf(dstpath, sizeof(dstpath), "%s/%u",
308 : dbspacedirname, relNumber);
309 : else
310 0 : snprintf(dstpath, sizeof(dstpath), "%s/%u.%u",
311 : dbspacedirname, relNumber, segno);
312 :
313 : /* OK, we're ready to perform the actual copy. */
314 14 : elog(DEBUG2, "copying %s to %s", srcpath, dstpath);
315 14 : copy_file(srcpath, dstpath);
316 : }
317 :
318 1054 : FreeDir(dbspace_dir);
319 :
320 : /*
321 : * copy_file() above has already called pg_flush_data() on the files
322 : * it created. Now we need to fsync those files, because a checkpoint
323 : * won't do it for us while we're in recovery. We do this in a
324 : * separate pass to allow the kernel to perform all the flushes
325 : * (especially the metadata ones) at once.
326 : */
327 1054 : dbspace_dir = AllocateDir(dbspacedirname);
328 296464 : while ((de = ReadDir(dbspace_dir, dbspacedirname)) != NULL)
329 : {
330 : RelFileNumber relNumber;
331 : ForkNumber forkNum;
332 : unsigned segno;
333 : char mainpath[MAXPGPATH];
334 :
335 : /* Skip anything that doesn't look like a relation data file. */
336 295410 : if (!parse_filename_for_nontemp_relation(de->d_name, &relNumber,
337 : &forkNum, &segno))
338 295396 : continue;
339 :
340 : /* Also skip it unless this is the init fork. */
341 291320 : if (forkNum != INIT_FORKNUM)
342 291306 : continue;
343 :
344 : /* Construct main fork pathname. */
345 14 : if (segno == 0)
346 14 : snprintf(mainpath, sizeof(mainpath), "%s/%u",
347 : dbspacedirname, relNumber);
348 : else
349 0 : snprintf(mainpath, sizeof(mainpath), "%s/%u.%u",
350 : dbspacedirname, relNumber, segno);
351 :
352 14 : fsync_fname(mainpath, false);
353 : }
354 :
355 1054 : FreeDir(dbspace_dir);
356 :
357 : /*
358 : * Lastly, fsync the database directory itself, ensuring the
359 : * filesystem remembers the file creations and deletions we've done.
360 : * We don't bother with this during a call that does only
361 : * UNLOGGED_RELATION_CLEANUP, because if recovery crashes before we
362 : * get to doing UNLOGGED_RELATION_INIT, we'll redo the cleanup step
363 : * too at the next startup attempt.
364 : */
365 1054 : fsync_fname(dbspacedirname, true);
366 : }
367 : }
368 :
369 : /*
370 : * Basic parsing of putative relation filenames.
371 : *
372 : * This function returns true if the file appears to be in the correct format
373 : * for a non-temporary relation and false otherwise.
374 : *
375 : * If it returns true, it sets *relnumber, *fork, and *segno to the values
376 : * extracted from the filename. If it returns false, these values are set to
377 : * InvalidRelFileNumber, InvalidForkNumber, and 0, respectively.
378 : */
379 : bool
380 1640982 : parse_filename_for_nontemp_relation(const char *name, RelFileNumber *relnumber,
381 : ForkNumber *fork, unsigned *segno)
382 : {
383 : unsigned long n,
384 : s;
385 : ForkNumber f;
386 : char *endp;
387 :
388 1640982 : *relnumber = InvalidRelFileNumber;
389 1640982 : *fork = InvalidForkNumber;
390 1640982 : *segno = 0;
391 :
392 : /*
393 : * Relation filenames should begin with a digit that is not a zero. By
394 : * rejecting cases involving leading zeroes, the caller can assume that
395 : * there's only one possible string of characters that could have produced
396 : * any given value for *relnumber.
397 : *
398 : * (To be clear, we don't expect files with names like 0017.3 to exist at
399 : * all -- but if 0017.3 does exist, it's a non-relation file, not part of
400 : * the main fork for relfilenode 17.)
401 : */
402 1640982 : if (name[0] < '1' || name[0] > '9')
403 19178 : return false;
404 :
405 : /*
406 : * Parse the leading digit string. If the value is out of range, we
407 : * conclude that this isn't a relation file at all.
408 : */
409 1621804 : errno = 0;
410 1621804 : n = strtoul(name, &endp, 10);
411 1621804 : if (errno || name == endp || n <= 0 || n > PG_UINT32_MAX)
412 0 : return false;
413 1621804 : name = endp;
414 :
415 : /* Check for a fork name. */
416 1621804 : if (*name != '_')
417 1222824 : f = MAIN_FORKNUM;
418 : else
419 : {
420 : int forkchar;
421 :
422 398980 : forkchar = forkname_chars(name + 1, &f);
423 398980 : if (forkchar <= 0)
424 0 : return false;
425 398980 : name += forkchar + 1;
426 : }
427 :
428 : /* Check for a segment number. */
429 1621804 : if (*name != '.')
430 1621804 : s = 0;
431 : else
432 : {
433 : /* Reject leading zeroes, just like we do for RelFileNumber. */
434 0 : if (name[1] < '1' || name[1] > '9')
435 0 : return false;
436 :
437 0 : errno = 0;
438 0 : s = strtoul(name + 1, &endp, 10);
439 0 : if (errno || name + 1 == endp || s <= 0 || s > PG_UINT32_MAX)
440 0 : return false;
441 0 : name = endp;
442 : }
443 :
444 : /* Now we should be at the end. */
445 1621804 : if (*name != '\0')
446 0 : return false;
447 :
448 : /* Set out parameters and return. */
449 1621804 : *relnumber = (RelFileNumber) n;
450 1621804 : *fork = f;
451 1621804 : *segno = (unsigned) s;
452 1621804 : return true;
453 : }
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