Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * xloginsert.c
4 : * Functions for constructing WAL records
5 : *
6 : * Constructing a WAL record begins with a call to XLogBeginInsert,
7 : * followed by a number of XLogRegister* calls. The registered data is
8 : * collected in private working memory, and finally assembled into a chain
9 : * of XLogRecData structs by a call to XLogRecordAssemble(). See
10 : * access/transam/README for details.
11 : *
12 : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
13 : * Portions Copyright (c) 1994, Regents of the University of California
14 : *
15 : * src/backend/access/transam/xloginsert.c
16 : *
17 : *-------------------------------------------------------------------------
18 : */
19 :
20 : #include "postgres.h"
21 :
22 : #ifdef USE_LZ4
23 : #include <lz4.h>
24 : #endif
25 :
26 : #ifdef USE_ZSTD
27 : #include <zstd.h>
28 : #endif
29 :
30 : #include "access/xact.h"
31 : #include "access/xlog.h"
32 : #include "access/xlog_internal.h"
33 : #include "access/xloginsert.h"
34 : #include "catalog/pg_control.h"
35 : #include "common/pg_lzcompress.h"
36 : #include "miscadmin.h"
37 : #include "pg_trace.h"
38 : #include "replication/origin.h"
39 : #include "storage/bufmgr.h"
40 : #include "storage/proc.h"
41 : #include "utils/memutils.h"
42 :
43 : /*
44 : * Guess the maximum buffer size required to store a compressed version of
45 : * backup block image.
46 : */
47 : #ifdef USE_LZ4
48 : #define LZ4_MAX_BLCKSZ LZ4_COMPRESSBOUND(BLCKSZ)
49 : #else
50 : #define LZ4_MAX_BLCKSZ 0
51 : #endif
52 :
53 : #ifdef USE_ZSTD
54 : #define ZSTD_MAX_BLCKSZ ZSTD_COMPRESSBOUND(BLCKSZ)
55 : #else
56 : #define ZSTD_MAX_BLCKSZ 0
57 : #endif
58 :
59 : #define PGLZ_MAX_BLCKSZ PGLZ_MAX_OUTPUT(BLCKSZ)
60 :
61 : /* Buffer size required to store a compressed version of backup block image */
62 : #define COMPRESS_BUFSIZE Max(Max(PGLZ_MAX_BLCKSZ, LZ4_MAX_BLCKSZ), ZSTD_MAX_BLCKSZ)
63 :
64 : /*
65 : * For each block reference registered with XLogRegisterBuffer, we fill in
66 : * a registered_buffer struct.
67 : */
68 : typedef struct
69 : {
70 : bool in_use; /* is this slot in use? */
71 : uint8 flags; /* REGBUF_* flags */
72 : RelFileLocator rlocator; /* identifies the relation and block */
73 : ForkNumber forkno;
74 : BlockNumber block;
75 : Page page; /* page content */
76 : uint32 rdata_len; /* total length of data in rdata chain */
77 : XLogRecData *rdata_head; /* head of the chain of data registered with
78 : * this block */
79 : XLogRecData *rdata_tail; /* last entry in the chain, or &rdata_head if
80 : * empty */
81 :
82 : XLogRecData bkp_rdatas[2]; /* temporary rdatas used to hold references to
83 : * backup block data in XLogRecordAssemble() */
84 :
85 : /* buffer to store a compressed version of backup block image */
86 : char compressed_page[COMPRESS_BUFSIZE];
87 : } registered_buffer;
88 :
89 : static registered_buffer *registered_buffers;
90 : static int max_registered_buffers; /* allocated size */
91 : static int max_registered_block_id = 0; /* highest block_id + 1 currently
92 : * registered */
93 :
94 : /*
95 : * A chain of XLogRecDatas to hold the "main data" of a WAL record, registered
96 : * with XLogRegisterData(...).
97 : */
98 : static XLogRecData *mainrdata_head;
99 : static XLogRecData *mainrdata_last = (XLogRecData *) &mainrdata_head;
100 : static uint64 mainrdata_len; /* total # of bytes in chain */
101 :
102 : /* flags for the in-progress insertion */
103 : static uint8 curinsert_flags = 0;
104 :
105 : /*
106 : * These are used to hold the record header while constructing a record.
107 : * 'hdr_scratch' is not a plain variable, but is palloc'd at initialization,
108 : * because we want it to be MAXALIGNed and padding bytes zeroed.
109 : *
110 : * For simplicity, it's allocated large enough to hold the headers for any
111 : * WAL record.
112 : */
113 : static XLogRecData hdr_rdt;
114 : static char *hdr_scratch = NULL;
115 :
116 : #define SizeOfXlogOrigin (sizeof(RepOriginId) + sizeof(char))
117 : #define SizeOfXLogTransactionId (sizeof(TransactionId) + sizeof(char))
118 :
119 : #define HEADER_SCRATCH_SIZE \
120 : (SizeOfXLogRecord + \
121 : MaxSizeOfXLogRecordBlockHeader * (XLR_MAX_BLOCK_ID + 1) + \
122 : SizeOfXLogRecordDataHeaderLong + SizeOfXlogOrigin + \
123 : SizeOfXLogTransactionId)
124 :
125 : /*
126 : * An array of XLogRecData structs, to hold registered data.
127 : */
128 : static XLogRecData *rdatas;
129 : static int num_rdatas; /* entries currently used */
130 : static int max_rdatas; /* allocated size */
131 :
132 : static bool begininsert_called = false;
133 :
134 : /* Memory context to hold the registered buffer and data references. */
135 : static MemoryContext xloginsert_cxt;
136 :
137 : static XLogRecData *XLogRecordAssemble(RmgrId rmid, uint8 info,
138 : XLogRecPtr RedoRecPtr, bool doPageWrites,
139 : XLogRecPtr *fpw_lsn, int *num_fpi,
140 : bool *topxid_included);
141 : static bool XLogCompressBackupBlock(char *page, uint16 hole_offset,
142 : uint16 hole_length, char *dest, uint16 *dlen);
143 :
144 : /*
145 : * Begin constructing a WAL record. This must be called before the
146 : * XLogRegister* functions and XLogInsert().
147 : */
148 : void
149 26493980 : XLogBeginInsert(void)
150 : {
151 : Assert(max_registered_block_id == 0);
152 : Assert(mainrdata_last == (XLogRecData *) &mainrdata_head);
153 : Assert(mainrdata_len == 0);
154 :
155 : /* cross-check on whether we should be here or not */
156 26493980 : if (!XLogInsertAllowed())
157 0 : elog(ERROR, "cannot make new WAL entries during recovery");
158 :
159 26493980 : if (begininsert_called)
160 0 : elog(ERROR, "XLogBeginInsert was already called");
161 :
162 26493980 : begininsert_called = true;
163 26493980 : }
164 :
165 : /*
166 : * Ensure that there are enough buffer and data slots in the working area,
167 : * for subsequent XLogRegisterBuffer, XLogRegisterData and XLogRegisterBufData
168 : * calls.
169 : *
170 : * There is always space for a small number of buffers and data chunks, enough
171 : * for most record types. This function is for the exceptional cases that need
172 : * more.
173 : */
174 : void
175 120694 : XLogEnsureRecordSpace(int max_block_id, int ndatas)
176 : {
177 : int nbuffers;
178 :
179 : /*
180 : * This must be called before entering a critical section, because
181 : * allocating memory inside a critical section can fail. repalloc() will
182 : * check the same, but better to check it here too so that we fail
183 : * consistently even if the arrays happen to be large enough already.
184 : */
185 : Assert(CritSectionCount == 0);
186 :
187 : /* the minimum values can't be decreased */
188 120694 : if (max_block_id < XLR_NORMAL_MAX_BLOCK_ID)
189 4198 : max_block_id = XLR_NORMAL_MAX_BLOCK_ID;
190 120694 : if (ndatas < XLR_NORMAL_RDATAS)
191 120642 : ndatas = XLR_NORMAL_RDATAS;
192 :
193 120694 : if (max_block_id > XLR_MAX_BLOCK_ID)
194 0 : elog(ERROR, "maximum number of WAL record block references exceeded");
195 120694 : nbuffers = max_block_id + 1;
196 :
197 120694 : if (nbuffers > max_registered_buffers)
198 : {
199 3028 : registered_buffers = (registered_buffer *)
200 3028 : repalloc(registered_buffers, sizeof(registered_buffer) * nbuffers);
201 :
202 : /*
203 : * At least the padding bytes in the structs must be zeroed, because
204 : * they are included in WAL data, but initialize it all for tidiness.
205 : */
206 3028 : MemSet(®istered_buffers[max_registered_buffers], 0,
207 : (nbuffers - max_registered_buffers) * sizeof(registered_buffer));
208 3028 : max_registered_buffers = nbuffers;
209 : }
210 :
211 120694 : if (ndatas > max_rdatas)
212 : {
213 32 : rdatas = (XLogRecData *) repalloc(rdatas, sizeof(XLogRecData) * ndatas);
214 32 : max_rdatas = ndatas;
215 : }
216 120694 : }
217 :
218 : /*
219 : * Reset WAL record construction buffers.
220 : */
221 : void
222 26548242 : XLogResetInsertion(void)
223 : {
224 : int i;
225 :
226 53670084 : for (i = 0; i < max_registered_block_id; i++)
227 27121842 : registered_buffers[i].in_use = false;
228 :
229 26548242 : num_rdatas = 0;
230 26548242 : max_registered_block_id = 0;
231 26548242 : mainrdata_len = 0;
232 26548242 : mainrdata_last = (XLogRecData *) &mainrdata_head;
233 26548242 : curinsert_flags = 0;
234 26548242 : begininsert_called = false;
235 26548242 : }
236 :
237 : /*
238 : * Register a reference to a buffer with the WAL record being constructed.
239 : * This must be called for every page that the WAL-logged operation modifies.
240 : */
241 : void
242 26794922 : XLogRegisterBuffer(uint8 block_id, Buffer buffer, uint8 flags)
243 : {
244 : registered_buffer *regbuf;
245 :
246 : /* NO_IMAGE doesn't make sense with FORCE_IMAGE */
247 : Assert(!((flags & REGBUF_FORCE_IMAGE) && (flags & (REGBUF_NO_IMAGE))));
248 : Assert(begininsert_called);
249 :
250 : /*
251 : * Ordinarily, buffer should be exclusive-locked and marked dirty before
252 : * we get here, otherwise we could end up violating one of the rules in
253 : * access/transam/README.
254 : *
255 : * Some callers intentionally register a clean page and never update that
256 : * page's LSN; in that case they can pass the flag REGBUF_NO_CHANGE to
257 : * bypass these checks.
258 : */
259 : #ifdef USE_ASSERT_CHECKING
260 : if (!(flags & REGBUF_NO_CHANGE))
261 : Assert(BufferIsExclusiveLocked(buffer) && BufferIsDirty(buffer));
262 : #endif
263 :
264 26794922 : if (block_id >= max_registered_block_id)
265 : {
266 26083154 : if (block_id >= max_registered_buffers)
267 0 : elog(ERROR, "too many registered buffers");
268 26083154 : max_registered_block_id = block_id + 1;
269 : }
270 :
271 26794922 : regbuf = ®istered_buffers[block_id];
272 :
273 26794922 : BufferGetTag(buffer, ®buf->rlocator, ®buf->forkno, ®buf->block);
274 26794922 : regbuf->page = BufferGetPage(buffer);
275 26794922 : regbuf->flags = flags;
276 26794922 : regbuf->rdata_tail = (XLogRecData *) ®buf->rdata_head;
277 26794922 : regbuf->rdata_len = 0;
278 :
279 : /*
280 : * Check that this page hasn't already been registered with some other
281 : * block_id.
282 : */
283 : #ifdef USE_ASSERT_CHECKING
284 : {
285 : int i;
286 :
287 : for (i = 0; i < max_registered_block_id; i++)
288 : {
289 : registered_buffer *regbuf_old = ®istered_buffers[i];
290 :
291 : if (i == block_id || !regbuf_old->in_use)
292 : continue;
293 :
294 : Assert(!RelFileLocatorEquals(regbuf_old->rlocator, regbuf->rlocator) ||
295 : regbuf_old->forkno != regbuf->forkno ||
296 : regbuf_old->block != regbuf->block);
297 : }
298 : }
299 : #endif
300 :
301 26794922 : regbuf->in_use = true;
302 26794922 : }
303 :
304 : /*
305 : * Like XLogRegisterBuffer, but for registering a block that's not in the
306 : * shared buffer pool (i.e. when you don't have a Buffer for it).
307 : */
308 : void
309 305638 : XLogRegisterBlock(uint8 block_id, RelFileLocator *rlocator, ForkNumber forknum,
310 : BlockNumber blknum, Page page, uint8 flags)
311 : {
312 : registered_buffer *regbuf;
313 :
314 : Assert(begininsert_called);
315 :
316 305638 : if (block_id >= max_registered_block_id)
317 305638 : max_registered_block_id = block_id + 1;
318 :
319 305638 : if (block_id >= max_registered_buffers)
320 0 : elog(ERROR, "too many registered buffers");
321 :
322 305638 : regbuf = ®istered_buffers[block_id];
323 :
324 305638 : regbuf->rlocator = *rlocator;
325 305638 : regbuf->forkno = forknum;
326 305638 : regbuf->block = blknum;
327 305638 : regbuf->page = page;
328 305638 : regbuf->flags = flags;
329 305638 : regbuf->rdata_tail = (XLogRecData *) ®buf->rdata_head;
330 305638 : regbuf->rdata_len = 0;
331 :
332 : /*
333 : * Check that this page hasn't already been registered with some other
334 : * block_id.
335 : */
336 : #ifdef USE_ASSERT_CHECKING
337 : {
338 : int i;
339 :
340 : for (i = 0; i < max_registered_block_id; i++)
341 : {
342 : registered_buffer *regbuf_old = ®istered_buffers[i];
343 :
344 : if (i == block_id || !regbuf_old->in_use)
345 : continue;
346 :
347 : Assert(!RelFileLocatorEquals(regbuf_old->rlocator, regbuf->rlocator) ||
348 : regbuf_old->forkno != regbuf->forkno ||
349 : regbuf_old->block != regbuf->block);
350 : }
351 : }
352 : #endif
353 :
354 305638 : regbuf->in_use = true;
355 305638 : }
356 :
357 : /*
358 : * Add data to the WAL record that's being constructed.
359 : *
360 : * The data is appended to the "main chunk", available at replay with
361 : * XLogRecGetData().
362 : */
363 : void
364 27297114 : XLogRegisterData(char *data, uint32 len)
365 : {
366 : XLogRecData *rdata;
367 :
368 : Assert(begininsert_called);
369 :
370 27297114 : if (num_rdatas >= max_rdatas)
371 0 : ereport(ERROR,
372 : (errmsg_internal("too much WAL data"),
373 : errdetail_internal("%d out of %d data segments are already in use.",
374 : num_rdatas, max_rdatas)));
375 27297114 : rdata = &rdatas[num_rdatas++];
376 :
377 27297114 : rdata->data = data;
378 27297114 : rdata->len = len;
379 :
380 : /*
381 : * we use the mainrdata_last pointer to track the end of the chain, so no
382 : * need to clear 'next' here.
383 : */
384 :
385 27297114 : mainrdata_last->next = rdata;
386 27297114 : mainrdata_last = rdata;
387 :
388 27297114 : mainrdata_len += len;
389 27297114 : }
390 :
391 : /*
392 : * Add buffer-specific data to the WAL record that's being constructed.
393 : *
394 : * Block_id must reference a block previously registered with
395 : * XLogRegisterBuffer(). If this is called more than once for the same
396 : * block_id, the data is appended.
397 : *
398 : * The maximum amount of data that can be registered per block is 65535
399 : * bytes. That should be plenty; if you need more than BLCKSZ bytes to
400 : * reconstruct the changes to the page, you might as well just log a full
401 : * copy of it. (the "main data" that's not associated with a block is not
402 : * limited)
403 : */
404 : void
405 37096776 : XLogRegisterBufData(uint8 block_id, char *data, uint32 len)
406 : {
407 : registered_buffer *regbuf;
408 : XLogRecData *rdata;
409 :
410 : Assert(begininsert_called);
411 :
412 : /* find the registered buffer struct */
413 37096776 : regbuf = ®istered_buffers[block_id];
414 37096776 : if (!regbuf->in_use)
415 0 : elog(ERROR, "no block with id %d registered with WAL insertion",
416 : block_id);
417 :
418 : /*
419 : * Check against max_rdatas and ensure we do not register more data per
420 : * buffer than can be handled by the physical data format; i.e. that
421 : * regbuf->rdata_len does not grow beyond what
422 : * XLogRecordBlockHeader->data_length can hold.
423 : */
424 37096776 : if (num_rdatas >= max_rdatas)
425 0 : ereport(ERROR,
426 : (errmsg_internal("too much WAL data"),
427 : errdetail_internal("%d out of %d data segments are already in use.",
428 : num_rdatas, max_rdatas)));
429 37096776 : if (regbuf->rdata_len + len > UINT16_MAX || len > UINT16_MAX)
430 0 : ereport(ERROR,
431 : (errmsg_internal("too much WAL data"),
432 : errdetail_internal("Registering more than maximum %u bytes allowed to block %u: current %u bytes, adding %u bytes.",
433 : UINT16_MAX, block_id, regbuf->rdata_len, len)));
434 :
435 37096776 : rdata = &rdatas[num_rdatas++];
436 :
437 37096776 : rdata->data = data;
438 37096776 : rdata->len = len;
439 :
440 37096776 : regbuf->rdata_tail->next = rdata;
441 37096776 : regbuf->rdata_tail = rdata;
442 37096776 : regbuf->rdata_len += len;
443 37096776 : }
444 :
445 : /*
446 : * Set insert status flags for the upcoming WAL record.
447 : *
448 : * The flags that can be used here are:
449 : * - XLOG_INCLUDE_ORIGIN, to determine if the replication origin should be
450 : * included in the record.
451 : * - XLOG_MARK_UNIMPORTANT, to signal that the record is not important for
452 : * durability, which allows to avoid triggering WAL archiving and other
453 : * background activity.
454 : */
455 : void
456 17332930 : XLogSetRecordFlags(uint8 flags)
457 : {
458 : Assert(begininsert_called);
459 17332930 : curinsert_flags |= flags;
460 17332930 : }
461 :
462 : /*
463 : * Insert an XLOG record having the specified RMID and info bytes, with the
464 : * body of the record being the data and buffer references registered earlier
465 : * with XLogRegister* calls.
466 : *
467 : * Returns XLOG pointer to end of record (beginning of next record).
468 : * This can be used as LSN for data pages affected by the logged action.
469 : * (LSN is the XLOG point up to which the XLOG must be flushed to disk
470 : * before the data page can be written out. This implements the basic
471 : * WAL rule "write the log before the data".)
472 : */
473 : XLogRecPtr
474 26493980 : XLogInsert(RmgrId rmid, uint8 info)
475 : {
476 : XLogRecPtr EndPos;
477 :
478 : /* XLogBeginInsert() must have been called. */
479 26493980 : if (!begininsert_called)
480 0 : elog(ERROR, "XLogBeginInsert was not called");
481 :
482 : /*
483 : * The caller can set rmgr bits, XLR_SPECIAL_REL_UPDATE and
484 : * XLR_CHECK_CONSISTENCY; the rest are reserved for use by me.
485 : */
486 26493980 : if ((info & ~(XLR_RMGR_INFO_MASK |
487 : XLR_SPECIAL_REL_UPDATE |
488 : XLR_CHECK_CONSISTENCY)) != 0)
489 0 : elog(PANIC, "invalid xlog info mask %02X", info);
490 :
491 : TRACE_POSTGRESQL_WAL_INSERT(rmid, info);
492 :
493 : /*
494 : * In bootstrap mode, we don't actually log anything but XLOG resources;
495 : * return a phony record pointer.
496 : */
497 26493980 : if (IsBootstrapProcessingMode() && rmid != RM_XLOG_ID)
498 : {
499 981120 : XLogResetInsertion();
500 981120 : EndPos = SizeOfXLogLongPHD; /* start of 1st chkpt record */
501 981120 : return EndPos;
502 : }
503 :
504 : do
505 : {
506 : XLogRecPtr RedoRecPtr;
507 : bool doPageWrites;
508 25524148 : bool topxid_included = false;
509 : XLogRecPtr fpw_lsn;
510 : XLogRecData *rdt;
511 25524148 : int num_fpi = 0;
512 :
513 : /*
514 : * Get values needed to decide whether to do full-page writes. Since
515 : * we don't yet have an insertion lock, these could change under us,
516 : * but XLogInsertRecord will recheck them once it has a lock.
517 : */
518 25524148 : GetFullPageWriteInfo(&RedoRecPtr, &doPageWrites);
519 :
520 25524148 : rdt = XLogRecordAssemble(rmid, info, RedoRecPtr, doPageWrites,
521 : &fpw_lsn, &num_fpi, &topxid_included);
522 :
523 25524148 : EndPos = XLogInsertRecord(rdt, fpw_lsn, curinsert_flags, num_fpi,
524 : topxid_included);
525 25524148 : } while (EndPos == InvalidXLogRecPtr);
526 :
527 25512860 : XLogResetInsertion();
528 :
529 25512860 : return EndPos;
530 : }
531 :
532 : /*
533 : * Assemble a WAL record from the registered data and buffers into an
534 : * XLogRecData chain, ready for insertion with XLogInsertRecord().
535 : *
536 : * The record header fields are filled in, except for the xl_prev field. The
537 : * calculated CRC does not include the record header yet.
538 : *
539 : * If there are any registered buffers, and a full-page image was not taken
540 : * of all of them, *fpw_lsn is set to the lowest LSN among such pages. This
541 : * signals that the assembled record is only good for insertion on the
542 : * assumption that the RedoRecPtr and doPageWrites values were up-to-date.
543 : *
544 : * *topxid_included is set if the topmost transaction ID is logged with the
545 : * current subtransaction.
546 : */
547 : static XLogRecData *
548 25524148 : XLogRecordAssemble(RmgrId rmid, uint8 info,
549 : XLogRecPtr RedoRecPtr, bool doPageWrites,
550 : XLogRecPtr *fpw_lsn, int *num_fpi, bool *topxid_included)
551 : {
552 : XLogRecData *rdt;
553 25524148 : uint64 total_len = 0;
554 : int block_id;
555 : pg_crc32c rdata_crc;
556 25524148 : registered_buffer *prev_regbuf = NULL;
557 : XLogRecData *rdt_datas_last;
558 : XLogRecord *rechdr;
559 25524148 : char *scratch = hdr_scratch;
560 :
561 : /*
562 : * Note: this function can be called multiple times for the same record.
563 : * All the modifications we do to the rdata chains below must handle that.
564 : */
565 :
566 : /* The record begins with the fixed-size header */
567 25524148 : rechdr = (XLogRecord *) scratch;
568 25524148 : scratch += SizeOfXLogRecord;
569 :
570 25524148 : hdr_rdt.next = NULL;
571 25524148 : rdt_datas_last = &hdr_rdt;
572 25524148 : hdr_rdt.data = hdr_scratch;
573 :
574 : /*
575 : * Enforce consistency checks for this record if user is looking for it.
576 : * Do this before at the beginning of this routine to give the possibility
577 : * for callers of XLogInsert() to pass XLR_CHECK_CONSISTENCY directly for
578 : * a record.
579 : */
580 25524148 : if (wal_consistency_checking[rmid])
581 6450 : info |= XLR_CHECK_CONSISTENCY;
582 :
583 : /*
584 : * Make an rdata chain containing all the data portions of all block
585 : * references. This includes the data for full-page images. Also append
586 : * the headers for the block references in the scratch buffer.
587 : */
588 25524148 : *fpw_lsn = InvalidXLogRecPtr;
589 51707202 : for (block_id = 0; block_id < max_registered_block_id; block_id++)
590 : {
591 26183054 : registered_buffer *regbuf = ®istered_buffers[block_id];
592 : bool needs_backup;
593 : bool needs_data;
594 : XLogRecordBlockHeader bkpb;
595 : XLogRecordBlockImageHeader bimg;
596 26183054 : XLogRecordBlockCompressHeader cbimg = {0};
597 : bool samerel;
598 26183054 : bool is_compressed = false;
599 : bool include_image;
600 :
601 26183054 : if (!regbuf->in_use)
602 21282 : continue;
603 :
604 : /* Determine if this block needs to be backed up */
605 26161772 : if (regbuf->flags & REGBUF_FORCE_IMAGE)
606 524802 : needs_backup = true;
607 25636970 : else if (regbuf->flags & REGBUF_NO_IMAGE)
608 436228 : needs_backup = false;
609 25200742 : else if (!doPageWrites)
610 453988 : needs_backup = false;
611 : else
612 : {
613 : /*
614 : * We assume page LSN is first data on *every* page that can be
615 : * passed to XLogInsert, whether it has the standard page layout
616 : * or not.
617 : */
618 24746754 : XLogRecPtr page_lsn = PageGetLSN(regbuf->page);
619 :
620 24746754 : needs_backup = (page_lsn <= RedoRecPtr);
621 24746754 : if (!needs_backup)
622 : {
623 24679374 : if (*fpw_lsn == InvalidXLogRecPtr || page_lsn < *fpw_lsn)
624 23903886 : *fpw_lsn = page_lsn;
625 : }
626 : }
627 :
628 : /* Determine if the buffer data needs to included */
629 26161772 : if (regbuf->rdata_len == 0)
630 5014282 : needs_data = false;
631 21147490 : else if ((regbuf->flags & REGBUF_KEEP_DATA) != 0)
632 584170 : needs_data = true;
633 : else
634 20563320 : needs_data = !needs_backup;
635 :
636 26161772 : bkpb.id = block_id;
637 26161772 : bkpb.fork_flags = regbuf->forkno;
638 26161772 : bkpb.data_length = 0;
639 :
640 26161772 : if ((regbuf->flags & REGBUF_WILL_INIT) == REGBUF_WILL_INIT)
641 384750 : bkpb.fork_flags |= BKPBLOCK_WILL_INIT;
642 :
643 : /*
644 : * If needs_backup is true or WAL checking is enabled for current
645 : * resource manager, log a full-page write for the current block.
646 : */
647 26161772 : include_image = needs_backup || (info & XLR_CHECK_CONSISTENCY) != 0;
648 :
649 26161772 : if (include_image)
650 : {
651 602622 : Page page = regbuf->page;
652 602622 : uint16 compressed_len = 0;
653 :
654 : /*
655 : * The page needs to be backed up, so calculate its hole length
656 : * and offset.
657 : */
658 602622 : if (regbuf->flags & REGBUF_STANDARD)
659 : {
660 : /* Assume we can omit data between pd_lower and pd_upper */
661 388042 : uint16 lower = ((PageHeader) page)->pd_lower;
662 388042 : uint16 upper = ((PageHeader) page)->pd_upper;
663 :
664 388042 : if (lower >= SizeOfPageHeaderData &&
665 386198 : upper > lower &&
666 : upper <= BLCKSZ)
667 : {
668 386198 : bimg.hole_offset = lower;
669 386198 : cbimg.hole_length = upper - lower;
670 : }
671 : else
672 : {
673 : /* No "hole" to remove */
674 1844 : bimg.hole_offset = 0;
675 1844 : cbimg.hole_length = 0;
676 : }
677 : }
678 : else
679 : {
680 : /* Not a standard page header, don't try to eliminate "hole" */
681 214580 : bimg.hole_offset = 0;
682 214580 : cbimg.hole_length = 0;
683 : }
684 :
685 : /*
686 : * Try to compress a block image if wal_compression is enabled
687 : */
688 602622 : if (wal_compression != WAL_COMPRESSION_NONE)
689 : {
690 : is_compressed =
691 0 : XLogCompressBackupBlock(page, bimg.hole_offset,
692 0 : cbimg.hole_length,
693 0 : regbuf->compressed_page,
694 : &compressed_len);
695 : }
696 :
697 : /*
698 : * Fill in the remaining fields in the XLogRecordBlockHeader
699 : * struct
700 : */
701 602622 : bkpb.fork_flags |= BKPBLOCK_HAS_IMAGE;
702 :
703 : /* Report a full page image constructed for the WAL record */
704 602622 : *num_fpi += 1;
705 :
706 : /*
707 : * Construct XLogRecData entries for the page content.
708 : */
709 602622 : rdt_datas_last->next = ®buf->bkp_rdatas[0];
710 602622 : rdt_datas_last = rdt_datas_last->next;
711 :
712 602622 : bimg.bimg_info = (cbimg.hole_length == 0) ? 0 : BKPIMAGE_HAS_HOLE;
713 :
714 : /*
715 : * If WAL consistency checking is enabled for the resource manager
716 : * of this WAL record, a full-page image is included in the record
717 : * for the block modified. During redo, the full-page is replayed
718 : * only if BKPIMAGE_APPLY is set.
719 : */
720 602622 : if (needs_backup)
721 592182 : bimg.bimg_info |= BKPIMAGE_APPLY;
722 :
723 602622 : if (is_compressed)
724 : {
725 : /* The current compression is stored in the WAL record */
726 0 : bimg.length = compressed_len;
727 :
728 : /* Set the compression method used for this block */
729 0 : switch ((WalCompression) wal_compression)
730 : {
731 0 : case WAL_COMPRESSION_PGLZ:
732 0 : bimg.bimg_info |= BKPIMAGE_COMPRESS_PGLZ;
733 0 : break;
734 :
735 0 : case WAL_COMPRESSION_LZ4:
736 : #ifdef USE_LZ4
737 0 : bimg.bimg_info |= BKPIMAGE_COMPRESS_LZ4;
738 : #else
739 : elog(ERROR, "LZ4 is not supported by this build");
740 : #endif
741 0 : break;
742 :
743 0 : case WAL_COMPRESSION_ZSTD:
744 : #ifdef USE_ZSTD
745 : bimg.bimg_info |= BKPIMAGE_COMPRESS_ZSTD;
746 : #else
747 0 : elog(ERROR, "zstd is not supported by this build");
748 : #endif
749 : break;
750 :
751 0 : case WAL_COMPRESSION_NONE:
752 : Assert(false); /* cannot happen */
753 0 : break;
754 : /* no default case, so that compiler will warn */
755 : }
756 :
757 0 : rdt_datas_last->data = regbuf->compressed_page;
758 0 : rdt_datas_last->len = compressed_len;
759 : }
760 : else
761 : {
762 602622 : bimg.length = BLCKSZ - cbimg.hole_length;
763 :
764 602622 : if (cbimg.hole_length == 0)
765 : {
766 216424 : rdt_datas_last->data = page;
767 216424 : rdt_datas_last->len = BLCKSZ;
768 : }
769 : else
770 : {
771 : /* must skip the hole */
772 386198 : rdt_datas_last->data = page;
773 386198 : rdt_datas_last->len = bimg.hole_offset;
774 :
775 386198 : rdt_datas_last->next = ®buf->bkp_rdatas[1];
776 386198 : rdt_datas_last = rdt_datas_last->next;
777 :
778 386198 : rdt_datas_last->data =
779 386198 : page + (bimg.hole_offset + cbimg.hole_length);
780 386198 : rdt_datas_last->len =
781 386198 : BLCKSZ - (bimg.hole_offset + cbimg.hole_length);
782 : }
783 : }
784 :
785 602622 : total_len += bimg.length;
786 : }
787 :
788 26161772 : if (needs_data)
789 : {
790 : /*
791 : * When copying to XLogRecordBlockHeader, the length is narrowed
792 : * to an uint16. Double-check that it is still correct.
793 : */
794 : Assert(regbuf->rdata_len <= UINT16_MAX);
795 :
796 : /*
797 : * Link the caller-supplied rdata chain for this buffer to the
798 : * overall list.
799 : */
800 21106754 : bkpb.fork_flags |= BKPBLOCK_HAS_DATA;
801 21106754 : bkpb.data_length = (uint16) regbuf->rdata_len;
802 21106754 : total_len += regbuf->rdata_len;
803 :
804 21106754 : rdt_datas_last->next = regbuf->rdata_head;
805 21106754 : rdt_datas_last = regbuf->rdata_tail;
806 : }
807 :
808 26161772 : if (prev_regbuf && RelFileLocatorEquals(regbuf->rlocator, prev_regbuf->rlocator))
809 : {
810 1312334 : samerel = true;
811 1312334 : bkpb.fork_flags |= BKPBLOCK_SAME_REL;
812 : }
813 : else
814 24849438 : samerel = false;
815 26161772 : prev_regbuf = regbuf;
816 :
817 : /* Ok, copy the header to the scratch buffer */
818 26161772 : memcpy(scratch, &bkpb, SizeOfXLogRecordBlockHeader);
819 26161772 : scratch += SizeOfXLogRecordBlockHeader;
820 26161772 : if (include_image)
821 : {
822 602622 : memcpy(scratch, &bimg, SizeOfXLogRecordBlockImageHeader);
823 602622 : scratch += SizeOfXLogRecordBlockImageHeader;
824 602622 : if (cbimg.hole_length != 0 && is_compressed)
825 : {
826 0 : memcpy(scratch, &cbimg,
827 : SizeOfXLogRecordBlockCompressHeader);
828 0 : scratch += SizeOfXLogRecordBlockCompressHeader;
829 : }
830 : }
831 26161772 : if (!samerel)
832 : {
833 24849438 : memcpy(scratch, ®buf->rlocator, sizeof(RelFileLocator));
834 24849438 : scratch += sizeof(RelFileLocator);
835 : }
836 26161772 : memcpy(scratch, ®buf->block, sizeof(BlockNumber));
837 26161772 : scratch += sizeof(BlockNumber);
838 : }
839 :
840 : /* followed by the record's origin, if any */
841 25524148 : if ((curinsert_flags & XLOG_INCLUDE_ORIGIN) &&
842 16251338 : replorigin_session_origin != InvalidRepOriginId)
843 : {
844 300724 : *(scratch++) = (char) XLR_BLOCK_ID_ORIGIN;
845 300724 : memcpy(scratch, &replorigin_session_origin, sizeof(replorigin_session_origin));
846 300724 : scratch += sizeof(replorigin_session_origin);
847 : }
848 :
849 : /* followed by toplevel XID, if not already included in previous record */
850 25524148 : if (IsSubxactTopXidLogPending())
851 : {
852 438 : TransactionId xid = GetTopTransactionIdIfAny();
853 :
854 : /* Set the flag that the top xid is included in the WAL */
855 438 : *topxid_included = true;
856 :
857 438 : *(scratch++) = (char) XLR_BLOCK_ID_TOPLEVEL_XID;
858 438 : memcpy(scratch, &xid, sizeof(TransactionId));
859 438 : scratch += sizeof(TransactionId);
860 : }
861 :
862 : /* followed by main data, if any */
863 25524148 : if (mainrdata_len > 0)
864 : {
865 24977396 : if (mainrdata_len > 255)
866 : {
867 : uint32 mainrdata_len_4b;
868 :
869 54810 : if (mainrdata_len > PG_UINT32_MAX)
870 0 : ereport(ERROR,
871 : (errmsg_internal("too much WAL data"),
872 : errdetail_internal("Main data length is %llu bytes for a maximum of %u bytes.",
873 : (unsigned long long) mainrdata_len,
874 : PG_UINT32_MAX)));
875 :
876 54810 : mainrdata_len_4b = (uint32) mainrdata_len;
877 54810 : *(scratch++) = (char) XLR_BLOCK_ID_DATA_LONG;
878 54810 : memcpy(scratch, &mainrdata_len_4b, sizeof(uint32));
879 54810 : scratch += sizeof(uint32);
880 : }
881 : else
882 : {
883 24922586 : *(scratch++) = (char) XLR_BLOCK_ID_DATA_SHORT;
884 24922586 : *(scratch++) = (uint8) mainrdata_len;
885 : }
886 24977396 : rdt_datas_last->next = mainrdata_head;
887 24977396 : rdt_datas_last = mainrdata_last;
888 24977396 : total_len += mainrdata_len;
889 : }
890 25524148 : rdt_datas_last->next = NULL;
891 :
892 25524148 : hdr_rdt.len = (scratch - hdr_scratch);
893 25524148 : total_len += hdr_rdt.len;
894 :
895 : /*
896 : * Calculate CRC of the data
897 : *
898 : * Note that the record header isn't added into the CRC initially since we
899 : * don't know the prev-link yet. Thus, the CRC will represent the CRC of
900 : * the whole record in the order: rdata, then backup blocks, then record
901 : * header.
902 : */
903 25524148 : INIT_CRC32C(rdata_crc);
904 25524148 : COMP_CRC32C(rdata_crc, hdr_scratch + SizeOfXLogRecord, hdr_rdt.len - SizeOfXLogRecord);
905 88040002 : for (rdt = hdr_rdt.next; rdt != NULL; rdt = rdt->next)
906 62515854 : COMP_CRC32C(rdata_crc, rdt->data, rdt->len);
907 :
908 : /*
909 : * Ensure that the XLogRecord is not too large.
910 : *
911 : * XLogReader machinery is only able to handle records up to a certain
912 : * size (ignoring machine resource limitations), so make sure that we will
913 : * not emit records larger than the sizes advertised to be supported.
914 : */
915 25524148 : if (total_len > XLogRecordMaxSize)
916 0 : ereport(ERROR,
917 : (errmsg_internal("oversized WAL record"),
918 : errdetail_internal("WAL record would be %llu bytes (of maximum %u bytes); rmid %u flags %u.",
919 : (unsigned long long) total_len, XLogRecordMaxSize, rmid, info)));
920 :
921 : /*
922 : * Fill in the fields in the record header. Prev-link is filled in later,
923 : * once we know where in the WAL the record will be inserted. The CRC does
924 : * not include the record header yet.
925 : */
926 25524148 : rechdr->xl_xid = GetCurrentTransactionIdIfAny();
927 25524148 : rechdr->xl_tot_len = (uint32) total_len;
928 25524148 : rechdr->xl_info = info;
929 25524148 : rechdr->xl_rmid = rmid;
930 25524148 : rechdr->xl_prev = InvalidXLogRecPtr;
931 25524148 : rechdr->xl_crc = rdata_crc;
932 :
933 25524148 : return &hdr_rdt;
934 : }
935 :
936 : /*
937 : * Create a compressed version of a backup block image.
938 : *
939 : * Returns false if compression fails (i.e., compressed result is actually
940 : * bigger than original). Otherwise, returns true and sets 'dlen' to
941 : * the length of compressed block image.
942 : */
943 : static bool
944 0 : XLogCompressBackupBlock(char *page, uint16 hole_offset, uint16 hole_length,
945 : char *dest, uint16 *dlen)
946 : {
947 0 : int32 orig_len = BLCKSZ - hole_length;
948 0 : int32 len = -1;
949 0 : int32 extra_bytes = 0;
950 : char *source;
951 : PGAlignedBlock tmp;
952 :
953 0 : if (hole_length != 0)
954 : {
955 : /* must skip the hole */
956 0 : source = tmp.data;
957 0 : memcpy(source, page, hole_offset);
958 0 : memcpy(source + hole_offset,
959 0 : page + (hole_offset + hole_length),
960 0 : BLCKSZ - (hole_length + hole_offset));
961 :
962 : /*
963 : * Extra data needs to be stored in WAL record for the compressed
964 : * version of block image if the hole exists.
965 : */
966 0 : extra_bytes = SizeOfXLogRecordBlockCompressHeader;
967 : }
968 : else
969 0 : source = page;
970 :
971 0 : switch ((WalCompression) wal_compression)
972 : {
973 0 : case WAL_COMPRESSION_PGLZ:
974 0 : len = pglz_compress(source, orig_len, dest, PGLZ_strategy_default);
975 0 : break;
976 :
977 0 : case WAL_COMPRESSION_LZ4:
978 : #ifdef USE_LZ4
979 0 : len = LZ4_compress_default(source, dest, orig_len,
980 : COMPRESS_BUFSIZE);
981 0 : if (len <= 0)
982 0 : len = -1; /* failure */
983 : #else
984 : elog(ERROR, "LZ4 is not supported by this build");
985 : #endif
986 0 : break;
987 :
988 0 : case WAL_COMPRESSION_ZSTD:
989 : #ifdef USE_ZSTD
990 : len = ZSTD_compress(dest, COMPRESS_BUFSIZE, source, orig_len,
991 : ZSTD_CLEVEL_DEFAULT);
992 : if (ZSTD_isError(len))
993 : len = -1; /* failure */
994 : #else
995 0 : elog(ERROR, "zstd is not supported by this build");
996 : #endif
997 : break;
998 :
999 0 : case WAL_COMPRESSION_NONE:
1000 : Assert(false); /* cannot happen */
1001 0 : break;
1002 : /* no default case, so that compiler will warn */
1003 : }
1004 :
1005 : /*
1006 : * We recheck the actual size even if compression reports success and see
1007 : * if the number of bytes saved by compression is larger than the length
1008 : * of extra data needed for the compressed version of block image.
1009 : */
1010 0 : if (len >= 0 &&
1011 0 : len + extra_bytes < orig_len)
1012 : {
1013 0 : *dlen = (uint16) len; /* successful compression */
1014 0 : return true;
1015 : }
1016 0 : return false;
1017 : }
1018 :
1019 : /*
1020 : * Determine whether the buffer referenced has to be backed up.
1021 : *
1022 : * Since we don't yet have the insert lock, fullPageWrites and runningBackups
1023 : * (which forces full-page writes) could change later, so the result should
1024 : * be used for optimization purposes only.
1025 : */
1026 : bool
1027 259538 : XLogCheckBufferNeedsBackup(Buffer buffer)
1028 : {
1029 : XLogRecPtr RedoRecPtr;
1030 : bool doPageWrites;
1031 : Page page;
1032 :
1033 259538 : GetFullPageWriteInfo(&RedoRecPtr, &doPageWrites);
1034 :
1035 259538 : page = BufferGetPage(buffer);
1036 :
1037 259538 : if (doPageWrites && PageGetLSN(page) <= RedoRecPtr)
1038 966 : return true; /* buffer requires backup */
1039 :
1040 258572 : return false; /* buffer does not need to be backed up */
1041 : }
1042 :
1043 : /*
1044 : * Write a backup block if needed when we are setting a hint. Note that
1045 : * this may be called for a variety of page types, not just heaps.
1046 : *
1047 : * Callable while holding just share lock on the buffer content.
1048 : *
1049 : * We can't use the plain backup block mechanism since that relies on the
1050 : * Buffer being exclusively locked. Since some modifications (setting LSN, hint
1051 : * bits) are allowed in a sharelocked buffer that can lead to wal checksum
1052 : * failures. So instead we copy the page and insert the copied data as normal
1053 : * record data.
1054 : *
1055 : * We only need to do something if page has not yet been full page written in
1056 : * this checkpoint round. The LSN of the inserted wal record is returned if we
1057 : * had to write, InvalidXLogRecPtr otherwise.
1058 : *
1059 : * It is possible that multiple concurrent backends could attempt to write WAL
1060 : * records. In that case, multiple copies of the same block would be recorded
1061 : * in separate WAL records by different backends, though that is still OK from
1062 : * a correctness perspective.
1063 : */
1064 : XLogRecPtr
1065 73184 : XLogSaveBufferForHint(Buffer buffer, bool buffer_std)
1066 : {
1067 73184 : XLogRecPtr recptr = InvalidXLogRecPtr;
1068 : XLogRecPtr lsn;
1069 : XLogRecPtr RedoRecPtr;
1070 :
1071 : /*
1072 : * Ensure no checkpoint can change our view of RedoRecPtr.
1073 : */
1074 : Assert((MyProc->delayChkptFlags & DELAY_CHKPT_START) != 0);
1075 :
1076 : /*
1077 : * Update RedoRecPtr so that we can make the right decision
1078 : */
1079 73184 : RedoRecPtr = GetRedoRecPtr();
1080 :
1081 : /*
1082 : * We assume page LSN is first data on *every* page that can be passed to
1083 : * XLogInsert, whether it has the standard page layout or not. Since we're
1084 : * only holding a share-lock on the page, we must take the buffer header
1085 : * lock when we look at the LSN.
1086 : */
1087 73184 : lsn = BufferGetLSNAtomic(buffer);
1088 :
1089 73184 : if (lsn <= RedoRecPtr)
1090 : {
1091 11338 : int flags = 0;
1092 : PGAlignedBlock copied_buffer;
1093 11338 : char *origdata = (char *) BufferGetBlock(buffer);
1094 : RelFileLocator rlocator;
1095 : ForkNumber forkno;
1096 : BlockNumber blkno;
1097 :
1098 : /*
1099 : * Copy buffer so we don't have to worry about concurrent hint bit or
1100 : * lsn updates. We assume pd_lower/upper cannot be changed without an
1101 : * exclusive lock, so the contents bkp are not racy.
1102 : */
1103 11338 : if (buffer_std)
1104 : {
1105 : /* Assume we can omit data between pd_lower and pd_upper */
1106 8588 : Page page = BufferGetPage(buffer);
1107 8588 : uint16 lower = ((PageHeader) page)->pd_lower;
1108 8588 : uint16 upper = ((PageHeader) page)->pd_upper;
1109 :
1110 8588 : memcpy(copied_buffer.data, origdata, lower);
1111 8588 : memcpy(copied_buffer.data + upper, origdata + upper, BLCKSZ - upper);
1112 : }
1113 : else
1114 2750 : memcpy(copied_buffer.data, origdata, BLCKSZ);
1115 :
1116 11338 : XLogBeginInsert();
1117 :
1118 11338 : if (buffer_std)
1119 8588 : flags |= REGBUF_STANDARD;
1120 :
1121 11338 : BufferGetTag(buffer, &rlocator, &forkno, &blkno);
1122 11338 : XLogRegisterBlock(0, &rlocator, forkno, blkno, copied_buffer.data, flags);
1123 :
1124 11338 : recptr = XLogInsert(RM_XLOG_ID, XLOG_FPI_FOR_HINT);
1125 : }
1126 :
1127 73184 : return recptr;
1128 : }
1129 :
1130 : /*
1131 : * Write a WAL record containing a full image of a page. Caller is responsible
1132 : * for writing the page to disk after calling this routine.
1133 : *
1134 : * Note: If you're using this function, you should be building pages in private
1135 : * memory and writing them directly to smgr. If you're using buffers, call
1136 : * log_newpage_buffer instead.
1137 : *
1138 : * If the page follows the standard page layout, with a PageHeader and unused
1139 : * space between pd_lower and pd_upper, set 'page_std' to true. That allows
1140 : * the unused space to be left out from the WAL record, making it smaller.
1141 : */
1142 : XLogRecPtr
1143 226828 : log_newpage(RelFileLocator *rlocator, ForkNumber forknum, BlockNumber blkno,
1144 : Page page, bool page_std)
1145 : {
1146 : int flags;
1147 : XLogRecPtr recptr;
1148 :
1149 226828 : flags = REGBUF_FORCE_IMAGE;
1150 226828 : if (page_std)
1151 226762 : flags |= REGBUF_STANDARD;
1152 :
1153 226828 : XLogBeginInsert();
1154 226828 : XLogRegisterBlock(0, rlocator, forknum, blkno, page, flags);
1155 226828 : recptr = XLogInsert(RM_XLOG_ID, XLOG_FPI);
1156 :
1157 : /*
1158 : * The page may be uninitialized. If so, we can't set the LSN because that
1159 : * would corrupt the page.
1160 : */
1161 226828 : if (!PageIsNew(page))
1162 : {
1163 226820 : PageSetLSN(page, recptr);
1164 : }
1165 :
1166 226828 : return recptr;
1167 : }
1168 :
1169 : /*
1170 : * Like log_newpage(), but allows logging multiple pages in one operation.
1171 : * It is more efficient than calling log_newpage() for each page separately,
1172 : * because we can write multiple pages in a single WAL record.
1173 : */
1174 : void
1175 33846 : log_newpages(RelFileLocator *rlocator, ForkNumber forknum, int num_pages,
1176 : BlockNumber *blknos, Page *pages, bool page_std)
1177 : {
1178 : int flags;
1179 : XLogRecPtr recptr;
1180 : int i;
1181 : int j;
1182 :
1183 33846 : flags = REGBUF_FORCE_IMAGE;
1184 33846 : if (page_std)
1185 33762 : flags |= REGBUF_STANDARD;
1186 :
1187 : /*
1188 : * Iterate over all the pages. They are collected into batches of
1189 : * XLR_MAX_BLOCK_ID pages, and a single WAL-record is written for each
1190 : * batch.
1191 : */
1192 33846 : XLogEnsureRecordSpace(XLR_MAX_BLOCK_ID - 1, 0);
1193 :
1194 33846 : i = 0;
1195 67692 : while (i < num_pages)
1196 : {
1197 33846 : int batch_start = i;
1198 : int nbatch;
1199 :
1200 33846 : XLogBeginInsert();
1201 :
1202 33846 : nbatch = 0;
1203 101318 : while (nbatch < XLR_MAX_BLOCK_ID && i < num_pages)
1204 : {
1205 67472 : XLogRegisterBlock(nbatch, rlocator, forknum, blknos[i], pages[i], flags);
1206 67472 : i++;
1207 67472 : nbatch++;
1208 : }
1209 :
1210 33846 : recptr = XLogInsert(RM_XLOG_ID, XLOG_FPI);
1211 :
1212 101318 : for (j = batch_start; j < i; j++)
1213 : {
1214 : /*
1215 : * The page may be uninitialized. If so, we can't set the LSN
1216 : * because that would corrupt the page.
1217 : */
1218 67472 : if (!PageIsNew(pages[j]))
1219 : {
1220 67468 : PageSetLSN(pages[j], recptr);
1221 : }
1222 : }
1223 : }
1224 33846 : }
1225 :
1226 : /*
1227 : * Write a WAL record containing a full image of a page.
1228 : *
1229 : * Caller should initialize the buffer and mark it dirty before calling this
1230 : * function. This function will set the page LSN.
1231 : *
1232 : * If the page follows the standard page layout, with a PageHeader and unused
1233 : * space between pd_lower and pd_upper, set 'page_std' to true. That allows
1234 : * the unused space to be left out from the WAL record, making it smaller.
1235 : */
1236 : XLogRecPtr
1237 221476 : log_newpage_buffer(Buffer buffer, bool page_std)
1238 : {
1239 221476 : Page page = BufferGetPage(buffer);
1240 : RelFileLocator rlocator;
1241 : ForkNumber forknum;
1242 : BlockNumber blkno;
1243 :
1244 : /* Shared buffers should be modified in a critical section. */
1245 : Assert(CritSectionCount > 0);
1246 :
1247 221476 : BufferGetTag(buffer, &rlocator, &forknum, &blkno);
1248 :
1249 221476 : return log_newpage(&rlocator, forknum, blkno, page, page_std);
1250 : }
1251 :
1252 : /*
1253 : * WAL-log a range of blocks in a relation.
1254 : *
1255 : * An image of all pages with block numbers 'startblk' <= X < 'endblk' is
1256 : * written to the WAL. If the range is large, this is done in multiple WAL
1257 : * records.
1258 : *
1259 : * If all page follows the standard page layout, with a PageHeader and unused
1260 : * space between pd_lower and pd_upper, set 'page_std' to true. That allows
1261 : * the unused space to be left out from the WAL records, making them smaller.
1262 : *
1263 : * NOTE: This function acquires exclusive-locks on the pages. Typically, this
1264 : * is used on a newly-built relation, and the caller is holding a
1265 : * AccessExclusiveLock on it, so no other backend can be accessing it at the
1266 : * same time. If that's not the case, you must ensure that this does not
1267 : * cause a deadlock through some other means.
1268 : */
1269 : void
1270 82356 : log_newpage_range(Relation rel, ForkNumber forknum,
1271 : BlockNumber startblk, BlockNumber endblk,
1272 : bool page_std)
1273 : {
1274 : int flags;
1275 : BlockNumber blkno;
1276 :
1277 82356 : flags = REGBUF_FORCE_IMAGE;
1278 82356 : if (page_std)
1279 908 : flags |= REGBUF_STANDARD;
1280 :
1281 : /*
1282 : * Iterate over all the pages in the range. They are collected into
1283 : * batches of XLR_MAX_BLOCK_ID pages, and a single WAL-record is written
1284 : * for each batch.
1285 : */
1286 82356 : XLogEnsureRecordSpace(XLR_MAX_BLOCK_ID - 1, 0);
1287 :
1288 82356 : blkno = startblk;
1289 144814 : while (blkno < endblk)
1290 : {
1291 : Buffer bufpack[XLR_MAX_BLOCK_ID];
1292 : XLogRecPtr recptr;
1293 : int nbufs;
1294 : int i;
1295 :
1296 62458 : CHECK_FOR_INTERRUPTS();
1297 :
1298 : /* Collect a batch of blocks. */
1299 62458 : nbufs = 0;
1300 290910 : while (nbufs < XLR_MAX_BLOCK_ID && blkno < endblk)
1301 : {
1302 228452 : Buffer buf = ReadBufferExtended(rel, forknum, blkno,
1303 : RBM_NORMAL, NULL);
1304 :
1305 228452 : LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
1306 :
1307 : /*
1308 : * Completely empty pages are not WAL-logged. Writing a WAL record
1309 : * would change the LSN, and we don't want that. We want the page
1310 : * to stay empty.
1311 : */
1312 228452 : if (!PageIsNew(BufferGetPage(buf)))
1313 227548 : bufpack[nbufs++] = buf;
1314 : else
1315 904 : UnlockReleaseBuffer(buf);
1316 228452 : blkno++;
1317 : }
1318 :
1319 : /* Nothing more to do if all remaining blocks were empty. */
1320 62458 : if (nbufs == 0)
1321 0 : break;
1322 :
1323 : /* Write WAL record for this batch. */
1324 62458 : XLogBeginInsert();
1325 :
1326 62458 : START_CRIT_SECTION();
1327 290006 : for (i = 0; i < nbufs; i++)
1328 : {
1329 227548 : MarkBufferDirty(bufpack[i]);
1330 227548 : XLogRegisterBuffer(i, bufpack[i], flags);
1331 : }
1332 :
1333 62458 : recptr = XLogInsert(RM_XLOG_ID, XLOG_FPI);
1334 :
1335 290006 : for (i = 0; i < nbufs; i++)
1336 : {
1337 227548 : PageSetLSN(BufferGetPage(bufpack[i]), recptr);
1338 227548 : UnlockReleaseBuffer(bufpack[i]);
1339 : }
1340 62458 : END_CRIT_SECTION();
1341 : }
1342 82356 : }
1343 :
1344 : /*
1345 : * Allocate working buffers needed for WAL record construction.
1346 : */
1347 : void
1348 29798 : InitXLogInsert(void)
1349 : {
1350 : #ifdef USE_ASSERT_CHECKING
1351 :
1352 : /*
1353 : * Check that any records assembled can be decoded. This is capped based
1354 : * on what XLogReader would require at its maximum bound. The XLOG_BLCKSZ
1355 : * addend covers the larger allocate_recordbuf() demand. This code path
1356 : * is called once per backend, more than enough for this check.
1357 : */
1358 : size_t max_required =
1359 : DecodeXLogRecordRequiredSpace(XLogRecordMaxSize + XLOG_BLCKSZ);
1360 :
1361 : Assert(AllocSizeIsValid(max_required));
1362 : #endif
1363 :
1364 : /* Initialize the working areas */
1365 29798 : if (xloginsert_cxt == NULL)
1366 : {
1367 29798 : xloginsert_cxt = AllocSetContextCreate(TopMemoryContext,
1368 : "WAL record construction",
1369 : ALLOCSET_DEFAULT_SIZES);
1370 : }
1371 :
1372 29798 : if (registered_buffers == NULL)
1373 : {
1374 29798 : registered_buffers = (registered_buffer *)
1375 29798 : MemoryContextAllocZero(xloginsert_cxt,
1376 : sizeof(registered_buffer) * (XLR_NORMAL_MAX_BLOCK_ID + 1));
1377 29798 : max_registered_buffers = XLR_NORMAL_MAX_BLOCK_ID + 1;
1378 : }
1379 29798 : if (rdatas == NULL)
1380 : {
1381 29798 : rdatas = MemoryContextAlloc(xloginsert_cxt,
1382 : sizeof(XLogRecData) * XLR_NORMAL_RDATAS);
1383 29798 : max_rdatas = XLR_NORMAL_RDATAS;
1384 : }
1385 :
1386 : /*
1387 : * Allocate a buffer to hold the header information for a WAL record.
1388 : */
1389 29798 : if (hdr_scratch == NULL)
1390 29798 : hdr_scratch = MemoryContextAllocZero(xloginsert_cxt,
1391 : HEADER_SCRATCH_SIZE);
1392 29798 : }
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