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1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * blkreftable.c
4 : : * Block reference tables.
5 : : *
6 : : * A block reference table is used to keep track of which blocks have
7 : : * been modified by WAL records within a certain LSN range.
8 : : *
9 : : * For each relation fork, we keep track of all blocks that have appeared
10 : : * in block reference in the WAL. We also keep track of the "limit block",
11 : : * which is the smallest relation length in blocks known to have occurred
12 : : * during that range of WAL records. This should be set to 0 if the relation
13 : : * fork is created or destroyed, and to the post-truncation length if
14 : : * truncated.
15 : : *
16 : : * Whenever we set the limit block, we also forget about any modified blocks
17 : : * beyond that point. Those blocks don't exist any more. Such blocks can
18 : : * later be marked as modified again; if that happens, it means the relation
19 : : * was re-extended.
20 : : *
21 : : * Portions Copyright (c) 2010-2026, PostgreSQL Global Development Group
22 : : *
23 : : * src/common/blkreftable.c
24 : : *
25 : : *-------------------------------------------------------------------------
26 : : */
27 : :
28 : :
29 : : #ifndef FRONTEND
30 : : #include "postgres.h"
31 : : #else
32 : : #include "postgres_fe.h"
33 : : #endif
34 : :
35 : : #ifdef FRONTEND
36 : : #include "common/logging.h"
37 : : #endif
38 : :
39 : : #include "common/blkreftable.h"
40 : : #include "common/hashfn.h"
41 : : #include "port/pg_crc32c.h"
42 : :
43 : : /*
44 : : * A block reference table keeps track of the status of each relation
45 : : * fork individually.
46 : : */
47 : : typedef struct BlockRefTableKey
48 : : {
49 : : RelFileLocator rlocator;
50 : : ForkNumber forknum;
51 : : } BlockRefTableKey;
52 : :
53 : : /*
54 : : * We could need to store data either for a relation in which only a
55 : : * tiny fraction of the blocks have been modified or for a relation in
56 : : * which nearly every block has been modified, and we want a
57 : : * space-efficient representation in both cases. To accomplish this,
58 : : * we divide the relation into chunks of 2^16 blocks and choose between
59 : : * an array representation and a bitmap representation for each chunk.
60 : : *
61 : : * When the number of modified blocks in a given chunk is small, we
62 : : * essentially store an array of block numbers, but we need not store the
63 : : * entire block number: instead, we store each block number as a 2-byte
64 : : * offset from the start of the chunk.
65 : : *
66 : : * When the number of modified blocks in a given chunk is large, we switch
67 : : * to a bitmap representation.
68 : : *
69 : : * These same basic representational choices are used both when a block
70 : : * reference table is stored in memory and when it is serialized to disk.
71 : : *
72 : : * In the in-memory representation, we initially allocate each chunk with
73 : : * space for a number of entries given by INITIAL_ENTRIES_PER_CHUNK and
74 : : * increase that as necessary until we reach MAX_ENTRIES_PER_CHUNK.
75 : : * Any chunk whose allocated size reaches MAX_ENTRIES_PER_CHUNK is converted
76 : : * to a bitmap, and thus never needs to grow further.
77 : : */
78 : : #define BLOCKS_PER_CHUNK (1 << 16)
79 : : #define BLOCKS_PER_ENTRY (BITS_PER_BYTE * sizeof(uint16))
80 : : #define MAX_ENTRIES_PER_CHUNK (BLOCKS_PER_CHUNK / BLOCKS_PER_ENTRY)
81 : : #define INITIAL_ENTRIES_PER_CHUNK 16
82 : : typedef uint16 *BlockRefTableChunk;
83 : :
84 : : /*
85 : : * State for one relation fork.
86 : : *
87 : : * 'rlocator' and 'forknum' identify the relation fork to which this entry
88 : : * pertains.
89 : : *
90 : : * 'limit_block' is the shortest known length of the relation in blocks
91 : : * within the LSN range covered by a particular block reference table.
92 : : * It should be set to 0 if the relation fork is created or dropped. If the
93 : : * relation fork is truncated, it should be set to the number of blocks that
94 : : * remain after truncation.
95 : : *
96 : : * 'nchunks' is the allocated length of each of the three arrays that follow.
97 : : * We can only represent the status of block numbers less than nchunks *
98 : : * BLOCKS_PER_CHUNK.
99 : : *
100 : : * 'chunk_size' is an array storing the allocated size of each chunk.
101 : : *
102 : : * 'chunk_usage' is an array storing the number of elements used in each
103 : : * chunk. If that value is less than MAX_ENTRIES_PER_CHUNK, the corresponding
104 : : * chunk is used as an array; else the corresponding chunk is used as a bitmap.
105 : : * When used as a bitmap, the least significant bit of the first array element
106 : : * is the status of the lowest-numbered block covered by this chunk.
107 : : *
108 : : * 'chunk_data' is the array of chunks.
109 : : */
110 : : struct BlockRefTableEntry
111 : : {
112 : : BlockRefTableKey key;
113 : : BlockNumber limit_block;
114 : : char status;
115 : : uint32 nchunks;
116 : : uint16 *chunk_size;
117 : : uint16 *chunk_usage;
118 : : BlockRefTableChunk *chunk_data;
119 : : };
120 : :
121 : : /* Declare and define a hash table over type BlockRefTableEntry. */
122 : : #define SH_PREFIX blockreftable
123 : : #define SH_ELEMENT_TYPE BlockRefTableEntry
124 : : #define SH_KEY_TYPE BlockRefTableKey
125 : : #define SH_KEY key
126 : : #define SH_HASH_KEY(tb, key) \
127 : : hash_bytes((const unsigned char *) &key, sizeof(BlockRefTableKey))
128 : : #define SH_EQUAL(tb, a, b) (memcmp(&a, &b, sizeof(BlockRefTableKey)) == 0)
129 : : #define SH_SCOPE static inline
130 : : #ifdef FRONTEND
131 : : #define SH_RAW_ALLOCATOR pg_malloc0
132 : : #endif
133 : : #define SH_DEFINE
134 : : #define SH_DECLARE
135 : : #include "lib/simplehash.h"
136 : :
137 : : /*
138 : : * A block reference table is basically just the hash table, but we don't
139 : : * want to expose that to outside callers.
140 : : *
141 : : * We keep track of the memory context in use explicitly too, so that it's
142 : : * easy to place all of our allocations in the same context.
143 : : */
144 : : struct BlockRefTable
145 : : {
146 : : blockreftable_hash *hash;
147 : : #ifndef FRONTEND
148 : : MemoryContext mcxt;
149 : : #endif
150 : : };
151 : :
152 : : /*
153 : : * On-disk serialization format for block reference table entries.
154 : : */
155 : : typedef struct BlockRefTableSerializedEntry
156 : : {
157 : : RelFileLocator rlocator;
158 : : ForkNumber forknum;
159 : : BlockNumber limit_block;
160 : : uint32 nchunks;
161 : : } BlockRefTableSerializedEntry;
162 : :
163 : : /*
164 : : * Buffer size, so that we avoid doing many small I/Os.
165 : : */
166 : : #define BUFSIZE 65536
167 : :
168 : : /*
169 : : * Ad-hoc buffer for file I/O.
170 : : */
171 : : typedef struct BlockRefTableBuffer
172 : : {
173 : : io_callback_fn io_callback;
174 : : void *io_callback_arg;
175 : : char data[BUFSIZE];
176 : : int used;
177 : : int cursor;
178 : : pg_crc32c crc;
179 : : } BlockRefTableBuffer;
180 : :
181 : : /*
182 : : * State for keeping track of progress while incrementally reading a block
183 : : * table reference file from disk.
184 : : *
185 : : * total_chunks means the number of chunks for the RelFileLocator/ForkNumber
186 : : * combination that is currently being read, and consumed_chunks is the number
187 : : * of those that have been read. (We always read all the information for
188 : : * a single chunk at one time, so we don't need to be able to represent the
189 : : * state where a chunk has been partially read.)
190 : : *
191 : : * chunk_size is the array of chunk sizes. The length is given by total_chunks.
192 : : *
193 : : * chunk_data holds the current chunk.
194 : : *
195 : : * chunk_position helps us figure out how much progress we've made in returning
196 : : * the block numbers for the current chunk to the caller. If the chunk is a
197 : : * bitmap, it's the number of bits we've scanned; otherwise, it's the number
198 : : * of chunk entries we've scanned.
199 : : */
200 : : struct BlockRefTableReader
201 : : {
202 : : BlockRefTableBuffer buffer;
203 : : char *error_filename;
204 : : report_error_fn error_callback;
205 : : void *error_callback_arg;
206 : : uint32 total_chunks;
207 : : uint32 consumed_chunks;
208 : : uint16 *chunk_size;
209 : : uint16 chunk_data[MAX_ENTRIES_PER_CHUNK];
210 : : uint32 chunk_position;
211 : : };
212 : :
213 : : /*
214 : : * State for keeping track of progress while incrementally writing a block
215 : : * reference table file to disk.
216 : : */
217 : : struct BlockRefTableWriter
218 : : {
219 : : BlockRefTableBuffer buffer;
220 : : };
221 : :
222 : : /* Function prototypes. */
223 : : static int BlockRefTableComparator(const void *a, const void *b);
224 : : static void BlockRefTableFlush(BlockRefTableBuffer *buffer);
225 : : static void BlockRefTableRead(BlockRefTableReader *reader, void *data,
226 : : int length);
227 : : static void BlockRefTableWrite(BlockRefTableBuffer *buffer, void *data,
228 : : int length);
229 : : static void BlockRefTableFileTerminate(BlockRefTableBuffer *buffer);
230 : :
231 : : /*
232 : : * Create an empty block reference table.
233 : : */
234 : : BlockRefTable *
235 : 0 : CreateEmptyBlockRefTable(void)
236 : : {
237 : 0 : BlockRefTable *brtab = palloc_object(BlockRefTable);
238 : :
239 : : /*
240 : : * Even completely empty database has a few hundred relation forks, so it
241 : : * seems best to size the hash on the assumption that we're going to have
242 : : * at least a few thousand entries.
243 : : */
244 : : #ifdef FRONTEND
245 : 0 : brtab->hash = blockreftable_create(4096, NULL);
246 : : #else
247 : 0 : brtab->mcxt = CurrentMemoryContext;
248 : 0 : brtab->hash = blockreftable_create(brtab->mcxt, 4096, NULL);
249 : : #endif
250 : :
251 : 0 : return brtab;
252 : 0 : }
253 : :
254 : : /*
255 : : * Set the "limit block" for a relation fork and forget any modified blocks
256 : : * with equal or higher block numbers.
257 : : *
258 : : * The "limit block" is the shortest known length of the relation within the
259 : : * range of WAL records covered by this block reference table.
260 : : */
261 : : void
262 : 0 : BlockRefTableSetLimitBlock(BlockRefTable *brtab,
263 : : const RelFileLocator *rlocator,
264 : : ForkNumber forknum,
265 : : BlockNumber limit_block)
266 : : {
267 : 0 : BlockRefTableEntry *brtentry;
268 : 0 : BlockRefTableKey key = {0}; /* make sure any padding is zero */
269 : 0 : bool found;
270 : :
271 : 0 : memcpy(&key.rlocator, rlocator, sizeof(RelFileLocator));
272 : 0 : key.forknum = forknum;
273 : 0 : brtentry = blockreftable_insert(brtab->hash, key, &found);
274 : :
275 [ # # ]: 0 : if (!found)
276 : : {
277 : : /*
278 : : * We have no existing data about this relation fork, so just record
279 : : * the limit_block value supplied by the caller, and make sure other
280 : : * parts of the entry are properly initialized.
281 : : */
282 : 0 : brtentry->limit_block = limit_block;
283 : 0 : brtentry->nchunks = 0;
284 : 0 : brtentry->chunk_size = NULL;
285 : 0 : brtentry->chunk_usage = NULL;
286 : 0 : brtentry->chunk_data = NULL;
287 : 0 : return;
288 : : }
289 : :
290 : 0 : BlockRefTableEntrySetLimitBlock(brtentry, limit_block);
291 [ # # ]: 0 : }
292 : :
293 : : /*
294 : : * Mark a block in a given relation fork as known to have been modified.
295 : : */
296 : : void
297 : 0 : BlockRefTableMarkBlockModified(BlockRefTable *brtab,
298 : : const RelFileLocator *rlocator,
299 : : ForkNumber forknum,
300 : : BlockNumber blknum)
301 : : {
302 : 0 : BlockRefTableEntry *brtentry;
303 : 0 : BlockRefTableKey key = {0}; /* make sure any padding is zero */
304 : 0 : bool found;
305 : : #ifndef FRONTEND
306 : 0 : MemoryContext oldcontext = MemoryContextSwitchTo(brtab->mcxt);
307 : : #endif
308 : :
309 : 0 : memcpy(&key.rlocator, rlocator, sizeof(RelFileLocator));
310 : 0 : key.forknum = forknum;
311 : 0 : brtentry = blockreftable_insert(brtab->hash, key, &found);
312 : :
313 [ # # ]: 0 : if (!found)
314 : : {
315 : : /*
316 : : * We want to set the initial limit block value to something higher
317 : : * than any legal block number. InvalidBlockNumber fits the bill.
318 : : */
319 : 0 : brtentry->limit_block = InvalidBlockNumber;
320 : 0 : brtentry->nchunks = 0;
321 : 0 : brtentry->chunk_size = NULL;
322 : 0 : brtentry->chunk_usage = NULL;
323 : 0 : brtentry->chunk_data = NULL;
324 : 0 : }
325 : :
326 : 0 : BlockRefTableEntryMarkBlockModified(brtentry, forknum, blknum);
327 : :
328 : : #ifndef FRONTEND
329 : 0 : MemoryContextSwitchTo(oldcontext);
330 : : #endif
331 : 0 : }
332 : :
333 : : /*
334 : : * Get an entry from a block reference table.
335 : : *
336 : : * If the entry does not exist, this function returns NULL. Otherwise, it
337 : : * returns the entry and sets *limit_block to the value from the entry.
338 : : */
339 : : BlockRefTableEntry *
340 : 0 : BlockRefTableGetEntry(BlockRefTable *brtab, const RelFileLocator *rlocator,
341 : : ForkNumber forknum, BlockNumber *limit_block)
342 : : {
343 : 0 : BlockRefTableKey key = {0}; /* make sure any padding is zero */
344 : 0 : BlockRefTableEntry *entry;
345 : :
346 [ # # ]: 0 : Assert(limit_block != NULL);
347 : :
348 : 0 : memcpy(&key.rlocator, rlocator, sizeof(RelFileLocator));
349 : 0 : key.forknum = forknum;
350 : 0 : entry = blockreftable_lookup(brtab->hash, key);
351 : :
352 [ # # ]: 0 : if (entry != NULL)
353 : 0 : *limit_block = entry->limit_block;
354 : :
355 : 0 : return entry;
356 : 0 : }
357 : :
358 : : /*
359 : : * Get block numbers from a table entry.
360 : : *
361 : : * 'blocks' must point to enough space to hold at least 'nblocks' block
362 : : * numbers, and any block numbers we manage to get will be written there.
363 : : * The return value is the number of block numbers actually written.
364 : : *
365 : : * We do not return block numbers unless they are greater than or equal to
366 : : * start_blkno and strictly less than stop_blkno.
367 : : */
368 : : int
369 : 0 : BlockRefTableEntryGetBlocks(BlockRefTableEntry *entry,
370 : : BlockNumber start_blkno,
371 : : BlockNumber stop_blkno,
372 : : BlockNumber *blocks,
373 : : int nblocks)
374 : : {
375 : 0 : uint32 start_chunkno;
376 : 0 : uint32 stop_chunkno;
377 : 0 : uint32 chunkno;
378 : 0 : int nresults = 0;
379 : :
380 [ # # ]: 0 : Assert(entry != NULL);
381 : :
382 : : /*
383 : : * Figure out which chunks could potentially contain blocks of interest.
384 : : *
385 : : * We need to be careful about overflow here, because stop_blkno could be
386 : : * InvalidBlockNumber or something very close to it.
387 : : */
388 : 0 : start_chunkno = start_blkno / BLOCKS_PER_CHUNK;
389 : 0 : stop_chunkno = stop_blkno / BLOCKS_PER_CHUNK;
390 [ # # ]: 0 : if ((stop_blkno % BLOCKS_PER_CHUNK) != 0)
391 : 0 : ++stop_chunkno;
392 [ # # ]: 0 : if (stop_chunkno > entry->nchunks)
393 : 0 : stop_chunkno = entry->nchunks;
394 : :
395 : : /*
396 : : * Loop over chunks.
397 : : */
398 [ # # ]: 0 : for (chunkno = start_chunkno; chunkno < stop_chunkno; ++chunkno)
399 : : {
400 : 0 : uint16 chunk_usage = entry->chunk_usage[chunkno];
401 : 0 : BlockRefTableChunk chunk_data = entry->chunk_data[chunkno];
402 : 0 : unsigned start_offset = 0;
403 : 0 : unsigned stop_offset = BLOCKS_PER_CHUNK;
404 : :
405 : : /*
406 : : * If the start and/or stop block number falls within this chunk, the
407 : : * whole chunk may not be of interest. Figure out which portion we
408 : : * care about, if it's not the whole thing.
409 : : */
410 [ # # ]: 0 : if (chunkno == start_chunkno)
411 : 0 : start_offset = start_blkno % BLOCKS_PER_CHUNK;
412 [ # # ]: 0 : if (chunkno == stop_chunkno - 1)
413 : : {
414 [ # # ]: 0 : Assert(stop_blkno > chunkno * BLOCKS_PER_CHUNK);
415 : 0 : stop_offset = stop_blkno - (chunkno * BLOCKS_PER_CHUNK);
416 [ # # ]: 0 : Assert(stop_offset <= BLOCKS_PER_CHUNK);
417 : 0 : }
418 : :
419 : : /*
420 : : * Handling differs depending on whether this is an array of offsets
421 : : * or a bitmap.
422 : : */
423 [ # # ]: 0 : if (chunk_usage == MAX_ENTRIES_PER_CHUNK)
424 : : {
425 : 0 : unsigned i;
426 : :
427 : : /* It's a bitmap, so test every relevant bit. */
428 [ # # ]: 0 : for (i = start_offset; i < stop_offset; ++i)
429 : : {
430 : 0 : uint16 w = chunk_data[i / BLOCKS_PER_ENTRY];
431 : :
432 [ # # ]: 0 : if ((w & (1 << (i % BLOCKS_PER_ENTRY))) != 0)
433 : : {
434 : 0 : BlockNumber blkno = chunkno * BLOCKS_PER_CHUNK + i;
435 : :
436 : 0 : blocks[nresults++] = blkno;
437 : :
438 : : /* Early exit if we run out of output space. */
439 [ # # ]: 0 : if (nresults == nblocks)
440 : 0 : return nresults;
441 [ # # ]: 0 : }
442 [ # # ]: 0 : }
443 [ # # ]: 0 : }
444 : : else
445 : : {
446 : 0 : unsigned i;
447 : :
448 : : /* It's an array of offsets, so check each one. */
449 [ # # ]: 0 : for (i = 0; i < chunk_usage; ++i)
450 : : {
451 : 0 : uint16 offset = chunk_data[i];
452 : :
453 [ # # # # ]: 0 : if (offset >= start_offset && offset < stop_offset)
454 : : {
455 : 0 : BlockNumber blkno = chunkno * BLOCKS_PER_CHUNK + offset;
456 : :
457 : 0 : blocks[nresults++] = blkno;
458 : :
459 : : /* Early exit if we run out of output space. */
460 [ # # ]: 0 : if (nresults == nblocks)
461 : 0 : return nresults;
462 [ # # ]: 0 : }
463 [ # # ]: 0 : }
464 [ # # ]: 0 : }
465 [ # # ]: 0 : }
466 : :
467 : 0 : return nresults;
468 : 0 : }
469 : :
470 : : /*
471 : : * Serialize a block reference table to a file.
472 : : */
473 : : void
474 : 0 : WriteBlockRefTable(BlockRefTable *brtab,
475 : : io_callback_fn write_callback,
476 : : void *write_callback_arg)
477 : : {
478 : 0 : BlockRefTableSerializedEntry *sdata = NULL;
479 : 0 : BlockRefTableBuffer buffer;
480 : 0 : uint32 magic = BLOCKREFTABLE_MAGIC;
481 : :
482 : : /* Prepare buffer. */
483 : 0 : memset(&buffer, 0, sizeof(BlockRefTableBuffer));
484 : 0 : buffer.io_callback = write_callback;
485 : 0 : buffer.io_callback_arg = write_callback_arg;
486 : 0 : INIT_CRC32C(buffer.crc);
487 : :
488 : : /* Write magic number. */
489 : 0 : BlockRefTableWrite(&buffer, &magic, sizeof(uint32));
490 : :
491 : : /* Write the entries, assuming there are some. */
492 [ # # ]: 0 : if (brtab->hash->members > 0)
493 : : {
494 : 0 : unsigned i = 0;
495 : 0 : blockreftable_iterator it;
496 : 0 : BlockRefTableEntry *brtentry;
497 : :
498 : : /* Extract entries into serializable format and sort them. */
499 : 0 : sdata =
500 : 0 : palloc_array(BlockRefTableSerializedEntry, brtab->hash->members);
501 : 0 : blockreftable_start_iterate(brtab->hash, &it);
502 [ # # ]: 0 : while ((brtentry = blockreftable_iterate(brtab->hash, &it)) != NULL)
503 : : {
504 : 0 : BlockRefTableSerializedEntry *sentry = &sdata[i++];
505 : :
506 : 0 : sentry->rlocator = brtentry->key.rlocator;
507 : 0 : sentry->forknum = brtentry->key.forknum;
508 : 0 : sentry->limit_block = brtentry->limit_block;
509 : 0 : sentry->nchunks = brtentry->nchunks;
510 : :
511 : : /* trim trailing zero entries */
512 [ # # # # ]: 0 : while (sentry->nchunks > 0 &&
513 : 0 : brtentry->chunk_usage[sentry->nchunks - 1] == 0)
514 : 0 : sentry->nchunks--;
515 : 0 : }
516 [ # # ]: 0 : Assert(i == brtab->hash->members);
517 : 0 : qsort(sdata, i, sizeof(BlockRefTableSerializedEntry),
518 : : BlockRefTableComparator);
519 : :
520 : : /* Loop over entries in sorted order and serialize each one. */
521 [ # # ]: 0 : for (i = 0; i < brtab->hash->members; ++i)
522 : : {
523 : 0 : BlockRefTableSerializedEntry *sentry = &sdata[i];
524 : 0 : BlockRefTableKey key = {0}; /* make sure any padding is zero */
525 : 0 : unsigned j;
526 : :
527 : : /* Write the serialized entry itself. */
528 : 0 : BlockRefTableWrite(&buffer, sentry,
529 : : sizeof(BlockRefTableSerializedEntry));
530 : :
531 : : /* Look up the original entry so we can access the chunks. */
532 : 0 : memcpy(&key.rlocator, &sentry->rlocator, sizeof(RelFileLocator));
533 : 0 : key.forknum = sentry->forknum;
534 : 0 : brtentry = blockreftable_lookup(brtab->hash, key);
535 [ # # ]: 0 : Assert(brtentry != NULL);
536 : :
537 : : /* Write the untruncated portion of the chunk length array. */
538 [ # # ]: 0 : if (sentry->nchunks != 0)
539 : 0 : BlockRefTableWrite(&buffer, brtentry->chunk_usage,
540 : 0 : sentry->nchunks * sizeof(uint16));
541 : :
542 : : /* Write the contents of each chunk. */
543 [ # # ]: 0 : for (j = 0; j < brtentry->nchunks; ++j)
544 : : {
545 [ # # ]: 0 : if (brtentry->chunk_usage[j] == 0)
546 : 0 : continue;
547 : 0 : BlockRefTableWrite(&buffer, brtentry->chunk_data[j],
548 : 0 : brtentry->chunk_usage[j] * sizeof(uint16));
549 : 0 : }
550 : 0 : }
551 : 0 : }
552 : :
553 : : /* Write out appropriate terminator and CRC and flush buffer. */
554 : 0 : BlockRefTableFileTerminate(&buffer);
555 : 0 : }
556 : :
557 : : /*
558 : : * Prepare to incrementally read a block reference table file.
559 : : *
560 : : * 'read_callback' is a function that can be called to read data from the
561 : : * underlying file (or other data source) into our internal buffer.
562 : : *
563 : : * 'read_callback_arg' is an opaque argument to be passed to read_callback.
564 : : *
565 : : * 'error_filename' is the filename that should be included in error messages
566 : : * if the file is found to be malformed. The value is not copied, so the
567 : : * caller should ensure that it remains valid until done with this
568 : : * BlockRefTableReader.
569 : : *
570 : : * 'error_callback' is a function to be called if the file is found to be
571 : : * malformed. This is not used for I/O errors, which must be handled internally
572 : : * by read_callback.
573 : : *
574 : : * 'error_callback_arg' is an opaque argument to be passed to error_callback.
575 : : */
576 : : BlockRefTableReader *
577 : 0 : CreateBlockRefTableReader(io_callback_fn read_callback,
578 : : void *read_callback_arg,
579 : : char *error_filename,
580 : : report_error_fn error_callback,
581 : : void *error_callback_arg)
582 : : {
583 : 0 : BlockRefTableReader *reader;
584 : 0 : uint32 magic;
585 : :
586 : : /* Initialize data structure. */
587 : 0 : reader = palloc0_object(BlockRefTableReader);
588 : 0 : reader->buffer.io_callback = read_callback;
589 : 0 : reader->buffer.io_callback_arg = read_callback_arg;
590 : 0 : reader->error_filename = error_filename;
591 : 0 : reader->error_callback = error_callback;
592 : 0 : reader->error_callback_arg = error_callback_arg;
593 : 0 : INIT_CRC32C(reader->buffer.crc);
594 : :
595 : : /* Verify magic number. */
596 : 0 : BlockRefTableRead(reader, &magic, sizeof(uint32));
597 [ # # ]: 0 : if (magic != BLOCKREFTABLE_MAGIC)
598 : 0 : error_callback(error_callback_arg,
599 : : "file \"%s\" has wrong magic number: expected %u, found %u",
600 : 0 : error_filename,
601 : 0 : BLOCKREFTABLE_MAGIC, magic);
602 : :
603 : 0 : return reader;
604 : 0 : }
605 : :
606 : : /*
607 : : * Read next relation fork covered by this block reference table file.
608 : : *
609 : : * After calling this function, you must call BlockRefTableReaderGetBlocks
610 : : * until it returns 0 before calling it again.
611 : : */
612 : : bool
613 : 0 : BlockRefTableReaderNextRelation(BlockRefTableReader *reader,
614 : : RelFileLocator *rlocator,
615 : : ForkNumber *forknum,
616 : : BlockNumber *limit_block)
617 : : {
618 : 0 : BlockRefTableSerializedEntry sentry;
619 : 0 : BlockRefTableSerializedEntry zentry = {0};
620 : :
621 : : /*
622 : : * Sanity check: caller must read all blocks from all chunks before moving
623 : : * on to the next relation.
624 : : */
625 [ # # ]: 0 : Assert(reader->total_chunks == reader->consumed_chunks);
626 : :
627 : : /* Read serialized entry. */
628 : 0 : BlockRefTableRead(reader, &sentry,
629 : : sizeof(BlockRefTableSerializedEntry));
630 : :
631 : : /*
632 : : * If we just read the sentinel entry indicating that we've reached the
633 : : * end, read and check the CRC.
634 : : */
635 [ # # ]: 0 : if (memcmp(&sentry, &zentry, sizeof(BlockRefTableSerializedEntry)) == 0)
636 : : {
637 : 0 : pg_crc32c expected_crc;
638 : 0 : pg_crc32c actual_crc;
639 : :
640 : : /*
641 : : * We want to know the CRC of the file excluding the 4-byte CRC
642 : : * itself, so copy the current value of the CRC accumulator before
643 : : * reading those bytes, and use the copy to finalize the calculation.
644 : : */
645 : 0 : expected_crc = reader->buffer.crc;
646 : 0 : FIN_CRC32C(expected_crc);
647 : :
648 : : /* Now we can read the actual value. */
649 : 0 : BlockRefTableRead(reader, &actual_crc, sizeof(pg_crc32c));
650 : :
651 : : /* Throw an error if there is a mismatch. */
652 [ # # ]: 0 : if (!EQ_CRC32C(expected_crc, actual_crc))
653 : 0 : reader->error_callback(reader->error_callback_arg,
654 : : "file \"%s\" has wrong checksum: expected %08X, found %08X",
655 : 0 : reader->error_filename, expected_crc, actual_crc);
656 : :
657 : 0 : return false;
658 : 0 : }
659 : :
660 : : /* Read chunk size array. */
661 [ # # ]: 0 : if (reader->chunk_size != NULL)
662 : 0 : pfree(reader->chunk_size);
663 : 0 : reader->chunk_size = palloc_array(uint16, sentry.nchunks);
664 : 0 : BlockRefTableRead(reader, reader->chunk_size,
665 : 0 : sentry.nchunks * sizeof(uint16));
666 : :
667 : : /* Set up for chunk scan. */
668 : 0 : reader->total_chunks = sentry.nchunks;
669 : 0 : reader->consumed_chunks = 0;
670 : :
671 : : /* Return data to caller. */
672 : 0 : memcpy(rlocator, &sentry.rlocator, sizeof(RelFileLocator));
673 : 0 : *forknum = sentry.forknum;
674 : 0 : *limit_block = sentry.limit_block;
675 : 0 : return true;
676 : 0 : }
677 : :
678 : : /*
679 : : * Get modified blocks associated with the relation fork returned by
680 : : * the most recent call to BlockRefTableReaderNextRelation.
681 : : *
682 : : * On return, block numbers will be written into the 'blocks' array, whose
683 : : * length should be passed via 'nblocks'. The return value is the number of
684 : : * entries actually written into the 'blocks' array, which may be less than
685 : : * 'nblocks' if we run out of modified blocks in the relation fork before
686 : : * we run out of room in the array.
687 : : */
688 : : unsigned
689 : 0 : BlockRefTableReaderGetBlocks(BlockRefTableReader *reader,
690 : : BlockNumber *blocks,
691 : : int nblocks)
692 : : {
693 : 0 : unsigned blocks_found = 0;
694 : :
695 : : /* Must provide space for at least one block number to be returned. */
696 [ # # ]: 0 : Assert(nblocks > 0);
697 : :
698 : : /* Loop collecting blocks to return to caller. */
699 : 0 : for (;;)
700 : : {
701 : 0 : uint16 next_chunk_size;
702 : :
703 : : /*
704 : : * If we've read at least one chunk, maybe it contains some block
705 : : * numbers that could satisfy caller's request.
706 : : */
707 [ # # ]: 0 : if (reader->consumed_chunks > 0)
708 : : {
709 : 0 : uint32 chunkno = reader->consumed_chunks - 1;
710 : 0 : uint16 chunk_size = reader->chunk_size[chunkno];
711 : :
712 [ # # ]: 0 : if (chunk_size == MAX_ENTRIES_PER_CHUNK)
713 : : {
714 : : /* Bitmap format, so search for bits that are set. */
715 [ # # # # ]: 0 : while (reader->chunk_position < BLOCKS_PER_CHUNK &&
716 : 0 : blocks_found < nblocks)
717 : : {
718 : 0 : uint16 chunkoffset = reader->chunk_position;
719 : 0 : uint16 w;
720 : :
721 : 0 : w = reader->chunk_data[chunkoffset / BLOCKS_PER_ENTRY];
722 [ # # ]: 0 : if ((w & (1u << (chunkoffset % BLOCKS_PER_ENTRY))) != 0)
723 : 0 : blocks[blocks_found++] =
724 : 0 : chunkno * BLOCKS_PER_CHUNK + chunkoffset;
725 : 0 : ++reader->chunk_position;
726 : 0 : }
727 : 0 : }
728 : : else
729 : : {
730 : : /* Not in bitmap format, so each entry is a 2-byte offset. */
731 [ # # # # ]: 0 : while (reader->chunk_position < chunk_size &&
732 : 0 : blocks_found < nblocks)
733 : : {
734 : 0 : blocks[blocks_found++] = chunkno * BLOCKS_PER_CHUNK
735 : 0 : + reader->chunk_data[reader->chunk_position];
736 : 0 : ++reader->chunk_position;
737 : : }
738 : : }
739 : 0 : }
740 : :
741 : : /* We found enough blocks, so we're done. */
742 [ # # ]: 0 : if (blocks_found >= nblocks)
743 : 0 : break;
744 : :
745 : : /*
746 : : * We didn't find enough blocks, so we must need the next chunk. If
747 : : * there are none left, though, then we're done anyway.
748 : : */
749 [ # # ]: 0 : if (reader->consumed_chunks == reader->total_chunks)
750 : 0 : break;
751 : :
752 : : /*
753 : : * Read data for next chunk and reset scan position to beginning of
754 : : * chunk. Note that the next chunk might be empty, in which case we
755 : : * consume the chunk without actually consuming any bytes from the
756 : : * underlying file.
757 : : */
758 : 0 : next_chunk_size = reader->chunk_size[reader->consumed_chunks];
759 [ # # ]: 0 : if (next_chunk_size > 0)
760 : 0 : BlockRefTableRead(reader, reader->chunk_data,
761 : 0 : next_chunk_size * sizeof(uint16));
762 : 0 : ++reader->consumed_chunks;
763 : 0 : reader->chunk_position = 0;
764 [ # # # ]: 0 : }
765 : :
766 : 0 : return blocks_found;
767 : 0 : }
768 : :
769 : : /*
770 : : * Release memory used while reading a block reference table from a file.
771 : : */
772 : : void
773 : 0 : DestroyBlockRefTableReader(BlockRefTableReader *reader)
774 : : {
775 [ # # ]: 0 : if (reader->chunk_size != NULL)
776 : : {
777 : 0 : pfree(reader->chunk_size);
778 : 0 : reader->chunk_size = NULL;
779 : 0 : }
780 : 0 : pfree(reader);
781 : 0 : }
782 : :
783 : : /*
784 : : * Prepare to write a block reference table file incrementally.
785 : : *
786 : : * Caller must be able to supply BlockRefTableEntry objects sorted in the
787 : : * appropriate order.
788 : : */
789 : : BlockRefTableWriter *
790 : 0 : CreateBlockRefTableWriter(io_callback_fn write_callback,
791 : : void *write_callback_arg)
792 : : {
793 : 0 : BlockRefTableWriter *writer;
794 : 0 : uint32 magic = BLOCKREFTABLE_MAGIC;
795 : :
796 : : /* Prepare buffer and CRC check and save callbacks. */
797 : 0 : writer = palloc0_object(BlockRefTableWriter);
798 : 0 : writer->buffer.io_callback = write_callback;
799 : 0 : writer->buffer.io_callback_arg = write_callback_arg;
800 : 0 : INIT_CRC32C(writer->buffer.crc);
801 : :
802 : : /* Write magic number. */
803 : 0 : BlockRefTableWrite(&writer->buffer, &magic, sizeof(uint32));
804 : :
805 : 0 : return writer;
806 : 0 : }
807 : :
808 : : /*
809 : : * Append one entry to a block reference table file.
810 : : *
811 : : * Note that entries must be written in the proper order, that is, sorted by
812 : : * tablespace, then database, then relfilenumber, then fork number. Caller
813 : : * is responsible for supplying data in the correct order. If that seems hard,
814 : : * use an in-memory BlockRefTable instead.
815 : : */
816 : : void
817 : 0 : BlockRefTableWriteEntry(BlockRefTableWriter *writer, BlockRefTableEntry *entry)
818 : : {
819 : 0 : BlockRefTableSerializedEntry sentry;
820 : 0 : unsigned j;
821 : :
822 : : /* Convert to serialized entry format. */
823 : 0 : sentry.rlocator = entry->key.rlocator;
824 : 0 : sentry.forknum = entry->key.forknum;
825 : 0 : sentry.limit_block = entry->limit_block;
826 : 0 : sentry.nchunks = entry->nchunks;
827 : :
828 : : /* Trim trailing zero entries. */
829 [ # # # # ]: 0 : while (sentry.nchunks > 0 && entry->chunk_usage[sentry.nchunks - 1] == 0)
830 : 0 : sentry.nchunks--;
831 : :
832 : : /* Write the serialized entry itself. */
833 : 0 : BlockRefTableWrite(&writer->buffer, &sentry,
834 : : sizeof(BlockRefTableSerializedEntry));
835 : :
836 : : /* Write the untruncated portion of the chunk length array. */
837 [ # # ]: 0 : if (sentry.nchunks != 0)
838 : 0 : BlockRefTableWrite(&writer->buffer, entry->chunk_usage,
839 : 0 : sentry.nchunks * sizeof(uint16));
840 : :
841 : : /* Write the contents of each chunk. */
842 [ # # ]: 0 : for (j = 0; j < entry->nchunks; ++j)
843 : : {
844 [ # # ]: 0 : if (entry->chunk_usage[j] == 0)
845 : 0 : continue;
846 : 0 : BlockRefTableWrite(&writer->buffer, entry->chunk_data[j],
847 : 0 : entry->chunk_usage[j] * sizeof(uint16));
848 : 0 : }
849 : 0 : }
850 : :
851 : : /*
852 : : * Finalize an incremental write of a block reference table file.
853 : : */
854 : : void
855 : 0 : DestroyBlockRefTableWriter(BlockRefTableWriter *writer)
856 : : {
857 : 0 : BlockRefTableFileTerminate(&writer->buffer);
858 : 0 : pfree(writer);
859 : 0 : }
860 : :
861 : : /*
862 : : * Allocate a standalone BlockRefTableEntry.
863 : : *
864 : : * When we're manipulating a full in-memory BlockRefTable, the entries are
865 : : * part of the hash table and are allocated by simplehash. This routine is
866 : : * used by callers that want to write out a BlockRefTable to a file without
867 : : * needing to store the whole thing in memory at once.
868 : : *
869 : : * Entries allocated by this function can be manipulated using the functions
870 : : * BlockRefTableEntrySetLimitBlock and BlockRefTableEntryMarkBlockModified
871 : : * and then written using BlockRefTableWriteEntry and freed using
872 : : * BlockRefTableFreeEntry.
873 : : */
874 : : BlockRefTableEntry *
875 : 0 : CreateBlockRefTableEntry(RelFileLocator rlocator, ForkNumber forknum)
876 : : {
877 : 0 : BlockRefTableEntry *entry = palloc0_object(BlockRefTableEntry);
878 : :
879 : 0 : memcpy(&entry->key.rlocator, &rlocator, sizeof(RelFileLocator));
880 : 0 : entry->key.forknum = forknum;
881 : 0 : entry->limit_block = InvalidBlockNumber;
882 : :
883 : 0 : return entry;
884 : 0 : }
885 : :
886 : : /*
887 : : * Update a BlockRefTableEntry with a new value for the "limit block" and
888 : : * forget any equal-or-higher-numbered modified blocks.
889 : : *
890 : : * The "limit block" is the shortest known length of the relation within the
891 : : * range of WAL records covered by this block reference table.
892 : : */
893 : : void
894 : 0 : BlockRefTableEntrySetLimitBlock(BlockRefTableEntry *entry,
895 : : BlockNumber limit_block)
896 : : {
897 : 0 : unsigned chunkno;
898 : 0 : unsigned limit_chunkno;
899 : 0 : unsigned limit_chunkoffset;
900 : 0 : BlockRefTableChunk limit_chunk;
901 : :
902 : : /* If we already have an equal or lower limit block, do nothing. */
903 [ # # ]: 0 : if (limit_block >= entry->limit_block)
904 : 0 : return;
905 : :
906 : : /* Record the new limit block value. */
907 : 0 : entry->limit_block = limit_block;
908 : :
909 : : /*
910 : : * Figure out which chunk would store the state of the new limit block,
911 : : * and which offset within that chunk.
912 : : */
913 : 0 : limit_chunkno = limit_block / BLOCKS_PER_CHUNK;
914 : 0 : limit_chunkoffset = limit_block % BLOCKS_PER_CHUNK;
915 : :
916 : : /*
917 : : * If the number of chunks is not large enough for any blocks with equal
918 : : * or higher block numbers to exist, then there is nothing further to do.
919 : : */
920 [ # # ]: 0 : if (limit_chunkno >= entry->nchunks)
921 : 0 : return;
922 : :
923 : : /* Discard entire contents of any higher-numbered chunks. */
924 [ # # ]: 0 : for (chunkno = limit_chunkno + 1; chunkno < entry->nchunks; ++chunkno)
925 : 0 : entry->chunk_usage[chunkno] = 0;
926 : :
927 : : /*
928 : : * Next, we need to discard any offsets within the chunk that would
929 : : * contain the limit_block. We must handle this differently depending on
930 : : * whether the chunk that would contain limit_block is a bitmap or an
931 : : * array of offsets.
932 : : */
933 : 0 : limit_chunk = entry->chunk_data[limit_chunkno];
934 [ # # ]: 0 : if (entry->chunk_usage[limit_chunkno] == MAX_ENTRIES_PER_CHUNK)
935 : : {
936 : 0 : unsigned chunkoffset;
937 : :
938 : : /* It's a bitmap. Unset bits. */
939 [ # # ]: 0 : for (chunkoffset = limit_chunkoffset; chunkoffset < BLOCKS_PER_CHUNK;
940 : 0 : ++chunkoffset)
941 : 0 : limit_chunk[chunkoffset / BLOCKS_PER_ENTRY] &=
942 : 0 : ~(1 << (chunkoffset % BLOCKS_PER_ENTRY));
943 : 0 : }
944 : : else
945 : : {
946 : 0 : unsigned i,
947 : 0 : j = 0;
948 : :
949 : : /* It's an offset array. Filter out large offsets. */
950 [ # # ]: 0 : for (i = 0; i < entry->chunk_usage[limit_chunkno]; ++i)
951 : : {
952 [ # # ]: 0 : Assert(j <= i);
953 [ # # ]: 0 : if (limit_chunk[i] < limit_chunkoffset)
954 : 0 : limit_chunk[j++] = limit_chunk[i];
955 : 0 : }
956 [ # # ]: 0 : Assert(j <= entry->chunk_usage[limit_chunkno]);
957 : 0 : entry->chunk_usage[limit_chunkno] = j;
958 : 0 : }
959 [ # # ]: 0 : }
960 : :
961 : : /*
962 : : * Mark a block in a given BlockRefTableEntry as known to have been modified.
963 : : */
964 : : void
965 : 0 : BlockRefTableEntryMarkBlockModified(BlockRefTableEntry *entry,
966 : : ForkNumber forknum,
967 : : BlockNumber blknum)
968 : : {
969 : 0 : unsigned chunkno;
970 : 0 : unsigned chunkoffset;
971 : 0 : unsigned i;
972 : :
973 : : /*
974 : : * Which chunk should store the state of this block? And what is the
975 : : * offset of this block relative to the start of that chunk?
976 : : */
977 : 0 : chunkno = blknum / BLOCKS_PER_CHUNK;
978 : 0 : chunkoffset = blknum % BLOCKS_PER_CHUNK;
979 : :
980 : : /*
981 : : * If 'nchunks' isn't big enough for us to be able to represent the state
982 : : * of this block, we need to enlarge our arrays.
983 : : */
984 [ # # ]: 0 : if (chunkno >= entry->nchunks)
985 : : {
986 : 0 : unsigned max_chunks;
987 : 0 : unsigned extra_chunks;
988 : :
989 : : /*
990 : : * New array size is a power of 2, at least 16, big enough so that
991 : : * chunkno will be a valid array index.
992 : : */
993 [ # # ]: 0 : max_chunks = Max(16, entry->nchunks);
994 [ # # ]: 0 : while (max_chunks < chunkno + 1)
995 : 0 : max_chunks *= 2;
996 : 0 : extra_chunks = max_chunks - entry->nchunks;
997 : :
998 [ # # ]: 0 : if (entry->nchunks == 0)
999 : : {
1000 : 0 : entry->chunk_size = palloc0_array(uint16, max_chunks);
1001 : 0 : entry->chunk_usage = palloc0_array(uint16, max_chunks);
1002 : 0 : entry->chunk_data = palloc0_array(BlockRefTableChunk, max_chunks);
1003 : 0 : }
1004 : : else
1005 : : {
1006 : 0 : entry->chunk_size = repalloc(entry->chunk_size,
1007 : 0 : sizeof(uint16) * max_chunks);
1008 : 0 : memset(&entry->chunk_size[entry->nchunks], 0,
1009 : : extra_chunks * sizeof(uint16));
1010 : 0 : entry->chunk_usage = repalloc(entry->chunk_usage,
1011 : 0 : sizeof(uint16) * max_chunks);
1012 : 0 : memset(&entry->chunk_usage[entry->nchunks], 0,
1013 : : extra_chunks * sizeof(uint16));
1014 : 0 : entry->chunk_data = repalloc(entry->chunk_data,
1015 : 0 : sizeof(BlockRefTableChunk) * max_chunks);
1016 : 0 : memset(&entry->chunk_data[entry->nchunks], 0,
1017 : : extra_chunks * sizeof(BlockRefTableChunk));
1018 : : }
1019 : 0 : entry->nchunks = max_chunks;
1020 : 0 : }
1021 : :
1022 : : /*
1023 : : * If the chunk that covers this block number doesn't exist yet, create it
1024 : : * as an array and add the appropriate offset to it. We make it pretty
1025 : : * small initially, because there might only be 1 or a few block
1026 : : * references in this chunk and we don't want to use up too much memory.
1027 : : */
1028 [ # # ]: 0 : if (entry->chunk_size[chunkno] == 0)
1029 : : {
1030 : 0 : entry->chunk_data[chunkno] =
1031 : 0 : palloc_array(uint16, INITIAL_ENTRIES_PER_CHUNK);
1032 : 0 : entry->chunk_size[chunkno] = INITIAL_ENTRIES_PER_CHUNK;
1033 : 0 : entry->chunk_data[chunkno][0] = chunkoffset;
1034 : 0 : entry->chunk_usage[chunkno] = 1;
1035 : 0 : return;
1036 : : }
1037 : :
1038 : : /*
1039 : : * If the number of entries in this chunk is already maximum, it must be a
1040 : : * bitmap. Just set the appropriate bit.
1041 : : */
1042 [ # # ]: 0 : if (entry->chunk_usage[chunkno] == MAX_ENTRIES_PER_CHUNK)
1043 : : {
1044 : 0 : BlockRefTableChunk chunk = entry->chunk_data[chunkno];
1045 : :
1046 : 0 : chunk[chunkoffset / BLOCKS_PER_ENTRY] |=
1047 : 0 : 1 << (chunkoffset % BLOCKS_PER_ENTRY);
1048 : : return;
1049 : 0 : }
1050 : :
1051 : : /*
1052 : : * There is an existing chunk and it's in array format. Let's find out
1053 : : * whether it already has an entry for this block. If so, we do not need
1054 : : * to do anything.
1055 : : */
1056 [ # # ]: 0 : for (i = 0; i < entry->chunk_usage[chunkno]; ++i)
1057 : : {
1058 [ # # ]: 0 : if (entry->chunk_data[chunkno][i] == chunkoffset)
1059 : 0 : return;
1060 : 0 : }
1061 : :
1062 : : /*
1063 : : * If the number of entries currently used is one less than the maximum,
1064 : : * it's time to convert to bitmap format.
1065 : : */
1066 [ # # ]: 0 : if (entry->chunk_usage[chunkno] == MAX_ENTRIES_PER_CHUNK - 1)
1067 : : {
1068 : 0 : BlockRefTableChunk newchunk;
1069 : 0 : unsigned j;
1070 : :
1071 : : /* Allocate a new chunk. */
1072 : 0 : newchunk = palloc0(MAX_ENTRIES_PER_CHUNK * sizeof(uint16));
1073 : :
1074 : : /* Set the bit for each existing entry. */
1075 [ # # ]: 0 : for (j = 0; j < entry->chunk_usage[chunkno]; ++j)
1076 : : {
1077 : 0 : unsigned coff = entry->chunk_data[chunkno][j];
1078 : :
1079 : 0 : newchunk[coff / BLOCKS_PER_ENTRY] |=
1080 : 0 : 1 << (coff % BLOCKS_PER_ENTRY);
1081 : 0 : }
1082 : :
1083 : : /* Set the bit for the new entry. */
1084 : 0 : newchunk[chunkoffset / BLOCKS_PER_ENTRY] |=
1085 : 0 : 1 << (chunkoffset % BLOCKS_PER_ENTRY);
1086 : :
1087 : : /* Swap the new chunk into place and update metadata. */
1088 : 0 : pfree(entry->chunk_data[chunkno]);
1089 : 0 : entry->chunk_data[chunkno] = newchunk;
1090 : 0 : entry->chunk_size[chunkno] = MAX_ENTRIES_PER_CHUNK;
1091 : 0 : entry->chunk_usage[chunkno] = MAX_ENTRIES_PER_CHUNK;
1092 : : return;
1093 : 0 : }
1094 : :
1095 : : /*
1096 : : * OK, we currently have an array, and we don't need to convert to a
1097 : : * bitmap, but we do need to add a new element. If there's not enough
1098 : : * room, we'll have to expand the array.
1099 : : */
1100 [ # # ]: 0 : if (entry->chunk_usage[chunkno] == entry->chunk_size[chunkno])
1101 : : {
1102 : 0 : unsigned newsize = entry->chunk_size[chunkno] * 2;
1103 : :
1104 [ # # ]: 0 : Assert(newsize <= MAX_ENTRIES_PER_CHUNK);
1105 : 0 : entry->chunk_data[chunkno] = repalloc(entry->chunk_data[chunkno],
1106 : 0 : newsize * sizeof(uint16));
1107 : 0 : entry->chunk_size[chunkno] = newsize;
1108 : 0 : }
1109 : :
1110 : : /* Now we can add the new entry. */
1111 : 0 : entry->chunk_data[chunkno][entry->chunk_usage[chunkno]] =
1112 : 0 : chunkoffset;
1113 : 0 : entry->chunk_usage[chunkno]++;
1114 [ # # ]: 0 : }
1115 : :
1116 : : /*
1117 : : * Release memory for a BlockRefTableEntry that was created by
1118 : : * CreateBlockRefTableEntry.
1119 : : */
1120 : : void
1121 : 0 : BlockRefTableFreeEntry(BlockRefTableEntry *entry)
1122 : : {
1123 [ # # ]: 0 : if (entry->chunk_size != NULL)
1124 : : {
1125 : 0 : pfree(entry->chunk_size);
1126 : 0 : entry->chunk_size = NULL;
1127 : 0 : }
1128 : :
1129 [ # # ]: 0 : if (entry->chunk_usage != NULL)
1130 : : {
1131 : 0 : pfree(entry->chunk_usage);
1132 : 0 : entry->chunk_usage = NULL;
1133 : 0 : }
1134 : :
1135 [ # # ]: 0 : if (entry->chunk_data != NULL)
1136 : : {
1137 : 0 : pfree(entry->chunk_data);
1138 : 0 : entry->chunk_data = NULL;
1139 : 0 : }
1140 : :
1141 : 0 : pfree(entry);
1142 : 0 : }
1143 : :
1144 : : /*
1145 : : * Comparator for BlockRefTableSerializedEntry objects.
1146 : : *
1147 : : * We make the tablespace OID the first column of the sort key to match
1148 : : * the on-disk tree structure.
1149 : : */
1150 : : static int
1151 : 0 : BlockRefTableComparator(const void *a, const void *b)
1152 : : {
1153 : 0 : const BlockRefTableSerializedEntry *sa = a;
1154 : 0 : const BlockRefTableSerializedEntry *sb = b;
1155 : :
1156 [ # # ]: 0 : if (sa->rlocator.spcOid > sb->rlocator.spcOid)
1157 : 0 : return 1;
1158 [ # # ]: 0 : if (sa->rlocator.spcOid < sb->rlocator.spcOid)
1159 : 0 : return -1;
1160 : :
1161 [ # # ]: 0 : if (sa->rlocator.dbOid > sb->rlocator.dbOid)
1162 : 0 : return 1;
1163 [ # # ]: 0 : if (sa->rlocator.dbOid < sb->rlocator.dbOid)
1164 : 0 : return -1;
1165 : :
1166 [ # # ]: 0 : if (sa->rlocator.relNumber > sb->rlocator.relNumber)
1167 : 0 : return 1;
1168 [ # # ]: 0 : if (sa->rlocator.relNumber < sb->rlocator.relNumber)
1169 : 0 : return -1;
1170 : :
1171 [ # # ]: 0 : if (sa->forknum > sb->forknum)
1172 : 0 : return 1;
1173 [ # # ]: 0 : if (sa->forknum < sb->forknum)
1174 : 0 : return -1;
1175 : :
1176 : 0 : return 0;
1177 : 0 : }
1178 : :
1179 : : /*
1180 : : * Flush any buffered data out of a BlockRefTableBuffer.
1181 : : */
1182 : : static void
1183 : 0 : BlockRefTableFlush(BlockRefTableBuffer *buffer)
1184 : : {
1185 : 0 : buffer->io_callback(buffer->io_callback_arg, buffer->data, buffer->used);
1186 : 0 : buffer->used = 0;
1187 : 0 : }
1188 : :
1189 : : /*
1190 : : * Read data from a BlockRefTableBuffer, and update the running CRC
1191 : : * calculation for the returned data (but not any data that we may have
1192 : : * buffered but not yet actually returned).
1193 : : */
1194 : : static void
1195 : 0 : BlockRefTableRead(BlockRefTableReader *reader, void *data, int length)
1196 : : {
1197 : 0 : BlockRefTableBuffer *buffer = &reader->buffer;
1198 : :
1199 : : /* Loop until read is fully satisfied. */
1200 [ # # ]: 0 : while (length > 0)
1201 : : {
1202 [ # # ]: 0 : if (buffer->cursor < buffer->used)
1203 : : {
1204 : : /*
1205 : : * If any buffered data is available, use that to satisfy as much
1206 : : * of the request as possible.
1207 : : */
1208 [ # # ]: 0 : int bytes_to_copy = Min(length, buffer->used - buffer->cursor);
1209 : :
1210 : 0 : memcpy(data, &buffer->data[buffer->cursor], bytes_to_copy);
1211 : 0 : COMP_CRC32C(buffer->crc, &buffer->data[buffer->cursor],
1212 : : bytes_to_copy);
1213 : 0 : buffer->cursor += bytes_to_copy;
1214 : 0 : data = ((char *) data) + bytes_to_copy;
1215 : 0 : length -= bytes_to_copy;
1216 : 0 : }
1217 [ # # ]: 0 : else if (length >= BUFSIZE)
1218 : : {
1219 : : /*
1220 : : * If the request length is long, read directly into caller's
1221 : : * buffer.
1222 : : */
1223 : 0 : int bytes_read;
1224 : :
1225 : 0 : bytes_read = buffer->io_callback(buffer->io_callback_arg,
1226 : 0 : data, length);
1227 : 0 : COMP_CRC32C(buffer->crc, data, bytes_read);
1228 : 0 : data = ((char *) data) + bytes_read;
1229 : 0 : length -= bytes_read;
1230 : :
1231 : : /* If we didn't get anything, that's bad. */
1232 [ # # ]: 0 : if (bytes_read == 0)
1233 : 0 : reader->error_callback(reader->error_callback_arg,
1234 : : "file \"%s\" ends unexpectedly",
1235 : 0 : reader->error_filename);
1236 : 0 : }
1237 : : else
1238 : : {
1239 : : /*
1240 : : * Refill our buffer.
1241 : : */
1242 : 0 : buffer->used = buffer->io_callback(buffer->io_callback_arg,
1243 : 0 : buffer->data, BUFSIZE);
1244 : 0 : buffer->cursor = 0;
1245 : :
1246 : : /* If we didn't get anything, that's bad. */
1247 [ # # ]: 0 : if (buffer->used == 0)
1248 : 0 : reader->error_callback(reader->error_callback_arg,
1249 : : "file \"%s\" ends unexpectedly",
1250 : 0 : reader->error_filename);
1251 : : }
1252 : : }
1253 : 0 : }
1254 : :
1255 : : /*
1256 : : * Supply data to a BlockRefTableBuffer for write to the underlying File,
1257 : : * and update the running CRC calculation for that data.
1258 : : */
1259 : : static void
1260 : 0 : BlockRefTableWrite(BlockRefTableBuffer *buffer, void *data, int length)
1261 : : {
1262 : : /* Update running CRC calculation. */
1263 : 0 : COMP_CRC32C(buffer->crc, data, length);
1264 : :
1265 : : /* If the new data can't fit into the buffer, flush the buffer. */
1266 [ # # ]: 0 : if (buffer->used + length > BUFSIZE)
1267 : : {
1268 : 0 : buffer->io_callback(buffer->io_callback_arg, buffer->data,
1269 : 0 : buffer->used);
1270 : 0 : buffer->used = 0;
1271 : 0 : }
1272 : :
1273 : : /* If the new data would fill the buffer, or more, write it directly. */
1274 [ # # ]: 0 : if (length >= BUFSIZE)
1275 : : {
1276 : 0 : buffer->io_callback(buffer->io_callback_arg, data, length);
1277 : 0 : return;
1278 : : }
1279 : :
1280 : : /* Otherwise, copy the new data into the buffer. */
1281 : 0 : memcpy(&buffer->data[buffer->used], data, length);
1282 : 0 : buffer->used += length;
1283 [ # # ]: 0 : Assert(buffer->used <= BUFSIZE);
1284 : 0 : }
1285 : :
1286 : : /*
1287 : : * Generate the sentinel and CRC required at the end of a block reference
1288 : : * table file and flush them out of our internal buffer.
1289 : : */
1290 : : static void
1291 : 0 : BlockRefTableFileTerminate(BlockRefTableBuffer *buffer)
1292 : : {
1293 : 0 : BlockRefTableSerializedEntry zentry = {0};
1294 : 0 : pg_crc32c crc;
1295 : :
1296 : : /* Write a sentinel indicating that there are no more entries. */
1297 : 0 : BlockRefTableWrite(buffer, &zentry,
1298 : : sizeof(BlockRefTableSerializedEntry));
1299 : :
1300 : : /*
1301 : : * Writing the checksum will perturb the ongoing checksum calculation, so
1302 : : * copy the state first and finalize the computation using the copy.
1303 : : */
1304 : 0 : crc = buffer->crc;
1305 : 0 : FIN_CRC32C(crc);
1306 : 0 : BlockRefTableWrite(buffer, &crc, sizeof(pg_crc32c));
1307 : :
1308 : : /* Flush any leftover data out of our buffer. */
1309 : 0 : BlockRefTableFlush(buffer);
1310 : 0 : }
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