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1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * hio.c
4 : : * POSTGRES heap access method input/output code.
5 : : *
6 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
7 : : * Portions Copyright (c) 1994, Regents of the University of California
8 : : *
9 : : *
10 : : * IDENTIFICATION
11 : : * src/backend/access/heap/hio.c
12 : : *
13 : : *-------------------------------------------------------------------------
14 : : */
15 : :
16 : : #include "postgres.h"
17 : :
18 : : #include "access/heapam.h"
19 : : #include "access/hio.h"
20 : : #include "access/htup_details.h"
21 : : #include "access/visibilitymap.h"
22 : : #include "storage/bufmgr.h"
23 : : #include "storage/freespace.h"
24 : : #include "storage/lmgr.h"
25 : :
26 : :
27 : : /*
28 : : * RelationPutHeapTuple - place tuple at specified page
29 : : *
30 : : * !!! EREPORT(ERROR) IS DISALLOWED HERE !!! Must PANIC on failure!!!
31 : : *
32 : : * Note - caller must hold BUFFER_LOCK_EXCLUSIVE on the buffer.
33 : : */
34 : : void
35 : 15772306 : RelationPutHeapTuple(Relation relation,
36 : : Buffer buffer,
37 : : HeapTuple tuple,
38 : : bool token)
39 : : {
40 : : Page pageHeader;
41 : : OffsetNumber offnum;
42 : :
43 : : /*
44 : : * A tuple that's being inserted speculatively should already have its
45 : : * token set.
46 : : */
47 : : Assert(!token || HeapTupleHeaderIsSpeculative(tuple->t_data));
48 : :
49 : : /*
50 : : * Do not allow tuples with invalid combinations of hint bits to be placed
51 : : * on a page. This combination is detected as corruption by the
52 : : * contrib/amcheck logic, so if you disable this assertion, make
53 : : * corresponding changes there.
54 : : */
55 : : Assert(!((tuple->t_data->t_infomask & HEAP_XMAX_COMMITTED) &&
56 : : (tuple->t_data->t_infomask & HEAP_XMAX_IS_MULTI)));
57 : :
58 : : /* Add the tuple to the page */
59 : 15772306 : pageHeader = BufferGetPage(buffer);
60 : :
61 : 15772306 : offnum = PageAddItem(pageHeader, tuple->t_data, tuple->t_len, InvalidOffsetNumber, false, true);
62 [ - + ]: 15772306 : if (offnum == InvalidOffsetNumber)
63 [ # # ]: 0 : elog(PANIC, "failed to add tuple to page");
64 : :
65 : : /* Update tuple->t_self to the actual position where it was stored */
66 : 15772306 : ItemPointerSet(&(tuple->t_self), BufferGetBlockNumber(buffer), offnum);
67 : :
68 : : /*
69 : : * Insert the correct position into CTID of the stored tuple, too (unless
70 : : * this is a speculative insertion, in which case the token is held in
71 : : * CTID field instead)
72 : : */
73 [ + + ]: 15772306 : if (!token)
74 : : {
75 : 15770076 : ItemId itemId = PageGetItemId(pageHeader, offnum);
76 : 15770076 : HeapTupleHeader item = (HeapTupleHeader) PageGetItem(pageHeader, itemId);
77 : :
78 : 15770076 : item->t_ctid = tuple->t_self;
79 : : }
80 : 15772306 : }
81 : :
82 : : /*
83 : : * Read in a buffer in mode, using bulk-insert strategy if bistate isn't NULL.
84 : : */
85 : : static Buffer
86 : 12057638 : ReadBufferBI(Relation relation, BlockNumber targetBlock,
87 : : ReadBufferMode mode, BulkInsertState bistate)
88 : : {
89 : : Buffer buffer;
90 : :
91 : : /* If not bulk-insert, exactly like ReadBuffer */
92 [ + + ]: 12057638 : if (!bistate)
93 : 9439540 : return ReadBufferExtended(relation, MAIN_FORKNUM, targetBlock,
94 : : mode, NULL);
95 : :
96 : : /* If we have the desired block already pinned, re-pin and return it */
97 [ + + ]: 2618098 : if (bistate->current_buf != InvalidBuffer)
98 : : {
99 [ + + ]: 2577847 : if (BufferGetBlockNumber(bistate->current_buf) == targetBlock)
100 : : {
101 : : /*
102 : : * Currently the LOCK variants are only used for extending
103 : : * relation, which should never reach this branch.
104 : : */
105 : : Assert(mode != RBM_ZERO_AND_LOCK &&
106 : : mode != RBM_ZERO_AND_CLEANUP_LOCK);
107 : :
108 : 2561606 : IncrBufferRefCount(bistate->current_buf);
109 : 2561606 : return bistate->current_buf;
110 : : }
111 : : /* ... else drop the old buffer */
112 : 16241 : ReleaseBuffer(bistate->current_buf);
113 : 16241 : bistate->current_buf = InvalidBuffer;
114 : : }
115 : :
116 : : /* Perform a read using the buffer strategy */
117 : 56492 : buffer = ReadBufferExtended(relation, MAIN_FORKNUM, targetBlock,
118 : : mode, bistate->strategy);
119 : :
120 : : /* Save the selected block as target for future inserts */
121 : 56492 : IncrBufferRefCount(buffer);
122 : 56492 : bistate->current_buf = buffer;
123 : :
124 : 56492 : return buffer;
125 : : }
126 : :
127 : : /*
128 : : * For each heap page which is all-visible, acquire a pin on the appropriate
129 : : * visibility map page, if we haven't already got one.
130 : : *
131 : : * To avoid complexity in the callers, either buffer1 or buffer2 may be
132 : : * InvalidBuffer if only one buffer is involved. For the same reason, block2
133 : : * may be smaller than block1.
134 : : *
135 : : * Returns whether buffer locks were temporarily released.
136 : : */
137 : : static bool
138 : 14271489 : GetVisibilityMapPins(Relation relation, Buffer buffer1, Buffer buffer2,
139 : : BlockNumber block1, BlockNumber block2,
140 : : Buffer *vmbuffer1, Buffer *vmbuffer2)
141 : : {
142 : : bool need_to_pin_buffer1;
143 : : bool need_to_pin_buffer2;
144 : 14271489 : bool released_locks = false;
145 : :
146 : : /*
147 : : * Swap buffers around to handle case of a single block/buffer, and to
148 : : * handle if lock ordering rules require to lock block2 first.
149 : : */
150 [ + + + + ]: 28542146 : if (!BufferIsValid(buffer1) ||
151 [ + + ]: 16483677 : (BufferIsValid(buffer2) && block1 > block2))
152 : : {
153 : 2182173 : Buffer tmpbuf = buffer1;
154 : 2182173 : Buffer *tmpvmbuf = vmbuffer1;
155 : 2182173 : BlockNumber tmpblock = block1;
156 : :
157 : 2182173 : buffer1 = buffer2;
158 : 2182173 : vmbuffer1 = vmbuffer2;
159 : 2182173 : block1 = block2;
160 : :
161 : 2182173 : buffer2 = tmpbuf;
162 : 2182173 : vmbuffer2 = tmpvmbuf;
163 : 2182173 : block2 = tmpblock;
164 : : }
165 : :
166 : : Assert(BufferIsValid(buffer1));
167 : : Assert(buffer2 == InvalidBuffer || block1 <= block2);
168 : :
169 : : while (1)
170 : : {
171 : : /* Figure out which pins we need but don't have. */
172 : 14271489 : need_to_pin_buffer1 = PageIsAllVisible(BufferGetPage(buffer1))
173 [ + + - + ]: 14271489 : && !visibilitymap_pin_ok(block1, *vmbuffer1);
174 : 14271489 : need_to_pin_buffer2 = buffer2 != InvalidBuffer
175 [ + + ]: 2213020 : && PageIsAllVisible(BufferGetPage(buffer2))
176 [ + + - + ]: 16484509 : && !visibilitymap_pin_ok(block2, *vmbuffer2);
177 [ + - + - ]: 14271489 : if (!need_to_pin_buffer1 && !need_to_pin_buffer2)
178 : 14271489 : break;
179 : :
180 : : /* We must unlock both buffers before doing any I/O. */
181 : 0 : released_locks = true;
182 : 0 : LockBuffer(buffer1, BUFFER_LOCK_UNLOCK);
183 [ # # # # ]: 0 : if (buffer2 != InvalidBuffer && buffer2 != buffer1)
184 : 0 : LockBuffer(buffer2, BUFFER_LOCK_UNLOCK);
185 : :
186 : : /* Get pins. */
187 [ # # ]: 0 : if (need_to_pin_buffer1)
188 : 0 : visibilitymap_pin(relation, block1, vmbuffer1);
189 [ # # ]: 0 : if (need_to_pin_buffer2)
190 : 0 : visibilitymap_pin(relation, block2, vmbuffer2);
191 : :
192 : : /* Relock buffers. */
193 : 0 : LockBuffer(buffer1, BUFFER_LOCK_EXCLUSIVE);
194 [ # # # # ]: 0 : if (buffer2 != InvalidBuffer && buffer2 != buffer1)
195 : 0 : LockBuffer(buffer2, BUFFER_LOCK_EXCLUSIVE);
196 : :
197 : : /*
198 : : * If there are two buffers involved and we pinned just one of them,
199 : : * it's possible that the second one became all-visible while we were
200 : : * busy pinning the first one. If it looks like that's a possible
201 : : * scenario, we'll need to make a second pass through this loop.
202 : : */
203 [ # # # # ]: 0 : if (buffer2 == InvalidBuffer || buffer1 == buffer2
204 [ # # # # ]: 0 : || (need_to_pin_buffer1 && need_to_pin_buffer2))
205 : : break;
206 : : }
207 : :
208 : 14271489 : return released_locks;
209 : : }
210 : :
211 : : /*
212 : : * Extend the relation. By multiple pages, if beneficial.
213 : : *
214 : : * If the caller needs multiple pages (num_pages > 1), we always try to extend
215 : : * by at least that much.
216 : : *
217 : : * If there is contention on the extension lock, we don't just extend "for
218 : : * ourselves", but we try to help others. We can do so by adding empty pages
219 : : * into the FSM. Typically there is no contention when we can't use the FSM.
220 : : *
221 : : * We do have to limit the number of pages to extend by to some value, as the
222 : : * buffers for all the extended pages need to, temporarily, be pinned. For now
223 : : * we define MAX_BUFFERS_TO_EXTEND_BY to be 64 buffers, it's hard to see
224 : : * benefits with higher numbers. This partially is because copyfrom.c's
225 : : * MAX_BUFFERED_TUPLES / MAX_BUFFERED_BYTES prevents larger multi_inserts.
226 : : *
227 : : * Returns a buffer for a newly extended block. If possible, the buffer is
228 : : * returned exclusively locked. *did_unlock is set to true if the lock had to
229 : : * be released, false otherwise.
230 : : *
231 : : *
232 : : * XXX: It would likely be beneficial for some workloads to extend more
233 : : * aggressively, e.g. using a heuristic based on the relation size.
234 : : */
235 : : static Buffer
236 : 153069 : RelationAddBlocks(Relation relation, BulkInsertState bistate,
237 : : int num_pages, bool use_fsm, bool *did_unlock)
238 : : {
239 : : #define MAX_BUFFERS_TO_EXTEND_BY 64
240 : : Buffer victim_buffers[MAX_BUFFERS_TO_EXTEND_BY];
241 : 153069 : BlockNumber first_block = InvalidBlockNumber;
242 : 153069 : BlockNumber last_block = InvalidBlockNumber;
243 : : uint32 extend_by_pages;
244 : : uint32 not_in_fsm_pages;
245 : : Buffer buffer;
246 : : Page page;
247 : :
248 : : /*
249 : : * Determine by how many pages to try to extend by.
250 : : */
251 [ + + + + ]: 153069 : if (bistate == NULL && !use_fsm)
252 : : {
253 : : /*
254 : : * If we have neither bistate, nor can use the FSM, we can't bulk
255 : : * extend - there'd be no way to find the additional pages.
256 : : */
257 : 211 : extend_by_pages = 1;
258 : : }
259 : : else
260 : : {
261 : : uint32 waitcount;
262 : :
263 : : /*
264 : : * Try to extend at least by the number of pages the caller needs. We
265 : : * can remember the additional pages (either via FSM or bistate).
266 : : */
267 : 152858 : extend_by_pages = num_pages;
268 : :
269 [ + + + + ]: 152858 : if (!RELATION_IS_LOCAL(relation))
270 : 94958 : waitcount = RelationExtensionLockWaiterCount(relation);
271 : : else
272 : 57900 : waitcount = 0;
273 : :
274 : : /*
275 : : * Multiply the number of pages to extend by the number of waiters. Do
276 : : * this even if we're not using the FSM, as it still relieves
277 : : * contention, by deferring the next time this backend needs to
278 : : * extend. In that case the extended pages will be found via
279 : : * bistate->next_free.
280 : : */
281 : 152858 : extend_by_pages += extend_by_pages * waitcount;
282 : :
283 : : /* ---
284 : : * If we previously extended using the same bistate, it's very likely
285 : : * we'll extend some more. Try to extend by as many pages as
286 : : * before. This can be important for performance for several reasons,
287 : : * including:
288 : : *
289 : : * - It prevents mdzeroextend() switching between extending the
290 : : * relation in different ways, which is inefficient for some
291 : : * filesystems.
292 : : *
293 : : * - Contention is often intermittent. Even if we currently don't see
294 : : * other waiters (see above), extending by larger amounts can
295 : : * prevent future contention.
296 : : * ---
297 : : */
298 [ + + ]: 152858 : if (bistate)
299 : 11597 : extend_by_pages = Max(extend_by_pages, bistate->already_extended_by);
300 : :
301 : : /*
302 : : * Can't extend by more than MAX_BUFFERS_TO_EXTEND_BY, we need to pin
303 : : * them all concurrently.
304 : : */
305 : 152858 : extend_by_pages = Min(extend_by_pages, MAX_BUFFERS_TO_EXTEND_BY);
306 : : }
307 : :
308 : : /*
309 : : * How many of the extended pages should be entered into the FSM?
310 : : *
311 : : * If we have a bistate, only enter pages that we don't need ourselves
312 : : * into the FSM. Otherwise every other backend will immediately try to
313 : : * use the pages this backend needs for itself, causing unnecessary
314 : : * contention. If we don't have a bistate, we can't avoid the FSM.
315 : : *
316 : : * Never enter the page returned into the FSM, we'll immediately use it.
317 : : */
318 [ + + + + ]: 153069 : if (num_pages > 1 && bistate == NULL)
319 : 312 : not_in_fsm_pages = 1;
320 : : else
321 : 152757 : not_in_fsm_pages = num_pages;
322 : :
323 : : /* prepare to put another buffer into the bistate */
324 [ + + + + ]: 153069 : if (bistate && bistate->current_buf != InvalidBuffer)
325 : : {
326 : 9159 : ReleaseBuffer(bistate->current_buf);
327 : 9159 : bistate->current_buf = InvalidBuffer;
328 : : }
329 : :
330 : : /*
331 : : * Extend the relation. We ask for the first returned page to be locked,
332 : : * so that we are sure that nobody has inserted into the page
333 : : * concurrently.
334 : : *
335 : : * With the current MAX_BUFFERS_TO_EXTEND_BY there's no danger of
336 : : * [auto]vacuum trying to truncate later pages as REL_TRUNCATE_MINIMUM is
337 : : * way larger.
338 : : */
339 [ + + ]: 153069 : first_block = ExtendBufferedRelBy(BMR_REL(relation), MAIN_FORKNUM,
340 : : bistate ? bistate->strategy : NULL,
341 : : EB_LOCK_FIRST,
342 : : extend_by_pages,
343 : : victim_buffers,
344 : : &extend_by_pages);
345 : 153068 : buffer = victim_buffers[0]; /* the buffer the function will return */
346 : 153068 : last_block = first_block + (extend_by_pages - 1);
347 : : Assert(first_block == BufferGetBlockNumber(buffer));
348 : :
349 : : /*
350 : : * Relation is now extended. Initialize the page. We do this here, before
351 : : * potentially releasing the lock on the page, because it allows us to
352 : : * double check that the page contents are empty (this should never
353 : : * happen, but if it does we don't want to risk wiping out valid data).
354 : : */
355 : 153068 : page = BufferGetPage(buffer);
356 [ - + ]: 153068 : if (!PageIsNew(page))
357 [ # # ]: 0 : elog(ERROR, "page %u of relation \"%s\" should be empty but is not",
358 : : first_block,
359 : : RelationGetRelationName(relation));
360 : :
361 : 153068 : PageInit(page, BufferGetPageSize(buffer), 0);
362 : 153068 : MarkBufferDirty(buffer);
363 : :
364 : : /*
365 : : * If we decided to put pages into the FSM, release the buffer lock (but
366 : : * not pin), we don't want to do IO while holding a buffer lock. This will
367 : : * necessitate a bit more extensive checking in our caller.
368 : : */
369 [ + + + + ]: 153068 : if (use_fsm && not_in_fsm_pages < extend_by_pages)
370 : : {
371 : 491 : LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
372 : 491 : *did_unlock = true;
373 : : }
374 : : else
375 : 152577 : *did_unlock = false;
376 : :
377 : : /*
378 : : * Relation is now extended. Release pins on all buffers, except for the
379 : : * first (which we'll return). If we decided to put pages into the FSM,
380 : : * we can do that as part of the same loop.
381 : : */
382 [ + + ]: 175426 : for (uint32 i = 1; i < extend_by_pages; i++)
383 : : {
384 : 22358 : BlockNumber curBlock = first_block + i;
385 : :
386 : : Assert(curBlock == BufferGetBlockNumber(victim_buffers[i]));
387 : : Assert(BlockNumberIsValid(curBlock));
388 : :
389 : 22358 : ReleaseBuffer(victim_buffers[i]);
390 : :
391 [ + + + + ]: 22358 : if (use_fsm && i >= not_in_fsm_pages)
392 : : {
393 : 6420 : Size freespace = BufferGetPageSize(victim_buffers[i]) -
394 : : SizeOfPageHeaderData;
395 : :
396 : 6420 : RecordPageWithFreeSpace(relation, curBlock, freespace);
397 : : }
398 : : }
399 : :
400 [ + + + + ]: 153068 : if (use_fsm && not_in_fsm_pages < extend_by_pages)
401 : : {
402 : 491 : BlockNumber first_fsm_block = first_block + not_in_fsm_pages;
403 : :
404 : 491 : FreeSpaceMapVacuumRange(relation, first_fsm_block, last_block);
405 : : }
406 : :
407 [ + + ]: 153068 : if (bistate)
408 : : {
409 : : /*
410 : : * Remember the additional pages we extended by, so we later can use
411 : : * them without looking into the FSM.
412 : : */
413 [ + + ]: 11597 : if (extend_by_pages > 1)
414 : : {
415 : 1238 : bistate->next_free = first_block + 1;
416 : 1238 : bistate->last_free = last_block;
417 : : }
418 : : else
419 : : {
420 : 10359 : bistate->next_free = InvalidBlockNumber;
421 : 10359 : bistate->last_free = InvalidBlockNumber;
422 : : }
423 : :
424 : : /* maintain bistate->current_buf */
425 : 11597 : IncrBufferRefCount(buffer);
426 : 11597 : bistate->current_buf = buffer;
427 : 11597 : bistate->already_extended_by += extend_by_pages;
428 : : }
429 : :
430 : 153068 : return buffer;
431 : : #undef MAX_BUFFERS_TO_EXTEND_BY
432 : : }
433 : :
434 : : /*
435 : : * RelationGetBufferForTuple
436 : : *
437 : : * Returns pinned and exclusive-locked buffer of a page in given relation
438 : : * with free space >= given len.
439 : : *
440 : : * If num_pages is > 1, we will try to extend the relation by at least that
441 : : * many pages when we decide to extend the relation. This is more efficient
442 : : * for callers that know they will need multiple pages
443 : : * (e.g. heap_multi_insert()).
444 : : *
445 : : * If otherBuffer is not InvalidBuffer, then it references a previously
446 : : * pinned buffer of another page in the same relation; on return, this
447 : : * buffer will also be exclusive-locked. (This case is used by heap_update;
448 : : * the otherBuffer contains the tuple being updated.)
449 : : *
450 : : * The reason for passing otherBuffer is that if two backends are doing
451 : : * concurrent heap_update operations, a deadlock could occur if they try
452 : : * to lock the same two buffers in opposite orders. To ensure that this
453 : : * can't happen, we impose the rule that buffers of a relation must be
454 : : * locked in increasing page number order. This is most conveniently done
455 : : * by having RelationGetBufferForTuple lock them both, with suitable care
456 : : * for ordering.
457 : : *
458 : : * NOTE: it is unlikely, but not quite impossible, for otherBuffer to be the
459 : : * same buffer we select for insertion of the new tuple (this could only
460 : : * happen if space is freed in that page after heap_update finds there's not
461 : : * enough there). In that case, the page will be pinned and locked only once.
462 : : *
463 : : * We also handle the possibility that the all-visible flag will need to be
464 : : * cleared on one or both pages. If so, pin on the associated visibility map
465 : : * page must be acquired before acquiring buffer lock(s), to avoid possibly
466 : : * doing I/O while holding buffer locks. The pins are passed back to the
467 : : * caller using the input-output arguments vmbuffer and vmbuffer_other.
468 : : * Note that in some cases the caller might have already acquired such pins,
469 : : * which is indicated by these arguments not being InvalidBuffer on entry.
470 : : *
471 : : * We normally use FSM to help us find free space. However,
472 : : * if HEAP_INSERT_SKIP_FSM is specified, we just append a new empty page to
473 : : * the end of the relation if the tuple won't fit on the current target page.
474 : : * This can save some cycles when we know the relation is new and doesn't
475 : : * contain useful amounts of free space.
476 : : *
477 : : * HEAP_INSERT_SKIP_FSM is also useful for non-WAL-logged additions to a
478 : : * relation, if the caller holds exclusive lock and is careful to invalidate
479 : : * relation's smgr_targblock before the first insertion --- that ensures that
480 : : * all insertions will occur into newly added pages and not be intermixed
481 : : * with tuples from other transactions. That way, a crash can't risk losing
482 : : * any committed data of other transactions. (See heap_insert's comments
483 : : * for additional constraints needed for safe usage of this behavior.)
484 : : *
485 : : * The caller can also provide a BulkInsertState object to optimize many
486 : : * insertions into the same relation. This keeps a pin on the current
487 : : * insertion target page (to save pin/unpin cycles) and also passes a
488 : : * BULKWRITE buffer selection strategy object to the buffer manager.
489 : : * Passing NULL for bistate selects the default behavior.
490 : : *
491 : : * We don't fill existing pages further than the fillfactor, except for large
492 : : * tuples in nearly-empty pages. This is OK since this routine is not
493 : : * consulted when updating a tuple and keeping it on the same page, which is
494 : : * the scenario fillfactor is meant to reserve space for.
495 : : *
496 : : * ereport(ERROR) is allowed here, so this routine *must* be called
497 : : * before any (unlogged) changes are made in buffer pool.
498 : : */
499 : : Buffer
500 : 14244416 : RelationGetBufferForTuple(Relation relation, Size len,
501 : : Buffer otherBuffer, uint32 options,
502 : : BulkInsertState bistate,
503 : : Buffer *vmbuffer, Buffer *vmbuffer_other,
504 : : int num_pages)
505 : : {
506 : 14244416 : bool use_fsm = !(options & HEAP_INSERT_SKIP_FSM);
507 : 14244416 : Buffer buffer = InvalidBuffer;
508 : : Page page;
509 : : Size nearlyEmptyFreeSpace,
510 : 14244416 : pageFreeSpace = 0,
511 : 14244416 : saveFreeSpace = 0,
512 : 14244416 : targetFreeSpace = 0;
513 : : BlockNumber targetBlock,
514 : : otherBlock;
515 : : bool unlockedTargetBuffer;
516 : : bool recheckVmPins;
517 : :
518 : 14244416 : len = MAXALIGN(len); /* be conservative */
519 : :
520 : : /* if the caller doesn't know by how many pages to extend, extend by 1 */
521 [ + + ]: 14244416 : if (num_pages <= 0)
522 : 13738708 : num_pages = 1;
523 : :
524 : : /* Bulk insert is not supported for updates, only inserts. */
525 : : Assert(otherBuffer == InvalidBuffer || !bistate);
526 : :
527 : : /*
528 : : * If we're gonna fail for oversize tuple, do it right away
529 : : */
530 [ - + ]: 14244416 : if (len > MaxHeapTupleSize)
531 [ # # ]: 0 : ereport(ERROR,
532 : : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
533 : : errmsg("row is too big: size %zu, maximum size %zu",
534 : : len, MaxHeapTupleSize)));
535 : :
536 : : /* Compute desired extra freespace due to fillfactor option */
537 [ + + ]: 14244416 : saveFreeSpace = RelationGetTargetPageFreeSpace(relation,
538 : : HEAP_DEFAULT_FILLFACTOR);
539 : :
540 : : /*
541 : : * Since pages without tuples can still have line pointers, we consider
542 : : * pages "empty" when the unavailable space is slight. This threshold is
543 : : * somewhat arbitrary, but it should prevent most unnecessary relation
544 : : * extensions while inserting large tuples into low-fillfactor tables.
545 : : */
546 : 14244416 : nearlyEmptyFreeSpace = MaxHeapTupleSize -
547 : : (MaxHeapTuplesPerPage / 8 * sizeof(ItemIdData));
548 [ + + ]: 14244416 : if (len + saveFreeSpace > nearlyEmptyFreeSpace)
549 : 4058 : targetFreeSpace = Max(len, nearlyEmptyFreeSpace);
550 : : else
551 : 14240358 : targetFreeSpace = len + saveFreeSpace;
552 : :
553 [ + + ]: 14244416 : if (otherBuffer != InvalidBuffer)
554 : 2198225 : otherBlock = BufferGetBlockNumber(otherBuffer);
555 : : else
556 : 12046191 : otherBlock = InvalidBlockNumber; /* just to keep compiler quiet */
557 : :
558 : : /*
559 : : * We first try to put the tuple on the same page we last inserted a tuple
560 : : * on, as cached in the BulkInsertState or relcache entry. If that
561 : : * doesn't work, we ask the Free Space Map to locate a suitable page.
562 : : * Since the FSM's info might be out of date, we have to be prepared to
563 : : * loop around and retry multiple times. (To ensure this isn't an infinite
564 : : * loop, we must update the FSM with the correct amount of free space on
565 : : * each page that proves not to be suitable.) If the FSM has no record of
566 : : * a page with enough free space, we give up and extend the relation.
567 : : *
568 : : * When use_fsm is false, we either put the tuple onto the existing target
569 : : * page or extend the relation.
570 : : */
571 [ + + + + ]: 14244416 : if (bistate && bistate->current_buf != InvalidBuffer)
572 : 2561606 : targetBlock = BufferGetBlockNumber(bistate->current_buf);
573 : : else
574 [ + + ]: 11682810 : targetBlock = RelationGetTargetBlock(relation);
575 : :
576 [ + + + + ]: 14244416 : if (targetBlock == InvalidBlockNumber && use_fsm)
577 : : {
578 : : /*
579 : : * We have no cached target page, so ask the FSM for an initial
580 : : * target.
581 : : */
582 : 60786 : targetBlock = GetPageWithFreeSpace(relation, targetFreeSpace);
583 : : }
584 : :
585 : : /*
586 : : * If the FSM knows nothing of the rel, try the last page before we give
587 : : * up and extend. This avoids one-tuple-per-page syndrome during
588 : : * bootstrapping or in a recently-started system.
589 : : */
590 [ + + ]: 14244416 : if (targetBlock == InvalidBlockNumber)
591 : : {
592 : 48888 : BlockNumber nblocks = RelationGetNumberOfBlocks(relation);
593 : :
594 [ + + ]: 48888 : if (nblocks > 0)
595 : 29088 : targetBlock = nblocks - 1;
596 : : }
597 : :
598 : 14244416 : loop:
599 [ + + ]: 14403149 : while (targetBlock != InvalidBlockNumber)
600 : : {
601 : : /*
602 : : * Read and exclusive-lock the target block, as well as the other
603 : : * block if one was given, taking suitable care with lock ordering and
604 : : * the possibility they are the same block.
605 : : *
606 : : * If the page-level all-visible flag is set, caller will need to
607 : : * clear both that and the corresponding visibility map bit. However,
608 : : * by the time we return, we'll have x-locked the buffer, and we don't
609 : : * want to do any I/O while in that state. So we check the bit here
610 : : * before taking the lock, and pin the page if it appears necessary.
611 : : * Checking without the lock creates a risk of getting the wrong
612 : : * answer, so we'll have to recheck after acquiring the lock.
613 : : */
614 [ + + ]: 14258035 : if (otherBuffer == InvalidBuffer)
615 : : {
616 : : /* easy case */
617 : 12057638 : buffer = ReadBufferBI(relation, targetBlock, RBM_NORMAL, bistate);
618 [ + + ]: 12057637 : if (PageIsAllVisible(BufferGetPage(buffer)))
619 : 14171 : visibilitymap_pin(relation, targetBlock, vmbuffer);
620 : :
621 : : /*
622 : : * If the page is empty, pin vmbuffer to set all_frozen bit later.
623 : : */
624 [ + + + + ]: 12063254 : if ((options & HEAP_INSERT_FROZEN) &&
625 : 5617 : (PageGetMaxOffsetNumber(BufferGetPage(buffer)) == 0))
626 : 1613 : visibilitymap_pin(relation, targetBlock, vmbuffer);
627 : :
628 : 12057637 : LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
629 : : }
630 [ + + ]: 2200397 : else if (otherBlock == targetBlock)
631 : : {
632 : : /* also easy case */
633 : 2152 : buffer = otherBuffer;
634 [ - + ]: 2152 : if (PageIsAllVisible(BufferGetPage(buffer)))
635 : 0 : visibilitymap_pin(relation, targetBlock, vmbuffer);
636 : 2152 : LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
637 : : }
638 [ + + ]: 2198245 : else if (otherBlock < targetBlock)
639 : : {
640 : : /* lock other buffer first */
641 : 2181341 : buffer = ReadBuffer(relation, targetBlock);
642 [ + + ]: 2181341 : if (PageIsAllVisible(BufferGetPage(buffer)))
643 : 861 : visibilitymap_pin(relation, targetBlock, vmbuffer);
644 : 2181341 : LockBuffer(otherBuffer, BUFFER_LOCK_EXCLUSIVE);
645 : 2181341 : LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
646 : : }
647 : : else
648 : : {
649 : : /* lock target buffer first */
650 : 16904 : buffer = ReadBuffer(relation, targetBlock);
651 [ + + ]: 16904 : if (PageIsAllVisible(BufferGetPage(buffer)))
652 : 184 : visibilitymap_pin(relation, targetBlock, vmbuffer);
653 : 16904 : LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
654 : 16904 : LockBuffer(otherBuffer, BUFFER_LOCK_EXCLUSIVE);
655 : : }
656 : :
657 : : /*
658 : : * We now have the target page (and the other buffer, if any) pinned
659 : : * and locked. However, since our initial PageIsAllVisible checks
660 : : * were performed before acquiring the lock, the results might now be
661 : : * out of date, either for the selected victim buffer, or for the
662 : : * other buffer passed by the caller. In that case, we'll need to
663 : : * give up our locks, go get the pin(s) we failed to get earlier, and
664 : : * re-lock. That's pretty painful, but hopefully shouldn't happen
665 : : * often.
666 : : *
667 : : * Note that there's a small possibility that we didn't pin the page
668 : : * above but still have the correct page pinned anyway, either because
669 : : * we've already made a previous pass through this loop, or because
670 : : * caller passed us the right page anyway.
671 : : *
672 : : * Note also that it's possible that by the time we get the pin and
673 : : * retake the buffer locks, the visibility map bit will have been
674 : : * cleared by some other backend anyway. In that case, we'll have
675 : : * done a bit of extra work for no gain, but there's no real harm
676 : : * done.
677 : : */
678 : 14258034 : GetVisibilityMapPins(relation, buffer, otherBuffer,
679 : : targetBlock, otherBlock, vmbuffer,
680 : : vmbuffer_other);
681 : :
682 : : /*
683 : : * Now we can check to see if there's enough free space here. If so,
684 : : * we're done.
685 : : */
686 : 14258034 : page = BufferGetPage(buffer);
687 : :
688 : : /*
689 : : * If necessary initialize page, it'll be used soon. We could avoid
690 : : * dirtying the buffer here, and rely on the caller to do so whenever
691 : : * it puts a tuple onto the page, but there seems not much benefit in
692 : : * doing so.
693 : : */
694 [ + + ]: 14258034 : if (PageIsNew(page))
695 : : {
696 : 17791 : PageInit(page, BufferGetPageSize(buffer), 0);
697 : 17791 : MarkBufferDirty(buffer);
698 : : }
699 : :
700 : 14258034 : pageFreeSpace = PageGetHeapFreeSpace(page);
701 [ + + ]: 14258034 : if (targetFreeSpace <= pageFreeSpace)
702 : : {
703 : : /* use this page as future insert target, too */
704 : 14091346 : RelationSetTargetBlock(relation, targetBlock);
705 : 14091346 : return buffer;
706 : : }
707 : :
708 : : /*
709 : : * Not enough space, so we must give up our page locks and pin (if
710 : : * any) and prepare to look elsewhere. We don't care which order we
711 : : * unlock the two buffers in, so this can be slightly simpler than the
712 : : * code above.
713 : : */
714 [ + + ]: 166688 : if (otherBuffer == InvalidBuffer)
715 : 151893 : UnlockReleaseBuffer(buffer);
716 [ + + ]: 14795 : else if (otherBlock != targetBlock)
717 : : {
718 : 12643 : UnlockReleaseBuffer(buffer);
719 : 12643 : LockBuffer(otherBuffer, BUFFER_LOCK_UNLOCK);
720 : : }
721 : : else
722 : 2152 : LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
723 : :
724 : : /* Is there an ongoing bulk extension? */
725 [ + + + + ]: 166688 : if (bistate && bistate->next_free != InvalidBlockNumber)
726 : : {
727 : : Assert(bistate->next_free <= bistate->last_free);
728 : :
729 : : /*
730 : : * We bulk extended the relation before, and there are still some
731 : : * unused pages from that extension, so we don't need to look in
732 : : * the FSM for a new page. But do record the free space from the
733 : : * last page, somebody might insert narrower tuples later.
734 : : */
735 [ + + ]: 16043 : if (use_fsm)
736 : 5531 : RecordPageWithFreeSpace(relation, targetBlock, pageFreeSpace);
737 : :
738 : 16043 : targetBlock = bistate->next_free;
739 [ + + ]: 16043 : if (bistate->next_free >= bistate->last_free)
740 : : {
741 : 984 : bistate->next_free = InvalidBlockNumber;
742 : 984 : bistate->last_free = InvalidBlockNumber;
743 : : }
744 : : else
745 : 15059 : bistate->next_free++;
746 : : }
747 [ + + ]: 150645 : else if (!use_fsm)
748 : : {
749 : : /* Without FSM, always fall out of the loop and extend */
750 : 7955 : break;
751 : : }
752 : : else
753 : : {
754 : : /*
755 : : * Update FSM as to condition of this page, and ask for another
756 : : * page to try.
757 : : */
758 : 142690 : targetBlock = RecordAndGetPageWithFreeSpace(relation,
759 : : targetBlock,
760 : : pageFreeSpace,
761 : : targetFreeSpace);
762 : : }
763 : : }
764 : :
765 : : /* Have to extend the relation */
766 : 153069 : buffer = RelationAddBlocks(relation, bistate, num_pages, use_fsm,
767 : : &unlockedTargetBuffer);
768 : :
769 : 153068 : targetBlock = BufferGetBlockNumber(buffer);
770 : 153068 : page = BufferGetPage(buffer);
771 : :
772 : : /*
773 : : * The page is empty, pin vmbuffer to set all_frozen bit. We don't want to
774 : : * do IO while the buffer is locked, so we unlock the page first if IO is
775 : : * needed (necessitating checks below).
776 : : */
777 [ + + ]: 153068 : if (options & HEAP_INSERT_FROZEN)
778 : : {
779 : : Assert(PageGetMaxOffsetNumber(page) == 0);
780 : :
781 [ + + ]: 368 : if (!visibilitymap_pin_ok(targetBlock, *vmbuffer))
782 : : {
783 [ + - ]: 341 : if (!unlockedTargetBuffer)
784 : 341 : LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
785 : 341 : unlockedTargetBuffer = true;
786 : 341 : visibilitymap_pin(relation, targetBlock, vmbuffer);
787 : : }
788 : : }
789 : :
790 : : /*
791 : : * Reacquire locks if necessary.
792 : : *
793 : : * If the target buffer was unlocked above, or is unlocked while
794 : : * reacquiring the lock on otherBuffer below, it's unlikely, but possible,
795 : : * that another backend used space on this page. We check for that below,
796 : : * and retry if necessary.
797 : : */
798 : 153068 : recheckVmPins = false;
799 [ + + ]: 153068 : if (unlockedTargetBuffer)
800 : : {
801 : : /* released lock on target buffer above */
802 [ - + ]: 832 : if (otherBuffer != InvalidBuffer)
803 : 0 : LockBuffer(otherBuffer, BUFFER_LOCK_EXCLUSIVE);
804 : 832 : LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
805 : 832 : recheckVmPins = true;
806 : : }
807 [ + + ]: 152236 : else if (otherBuffer != InvalidBuffer)
808 : : {
809 : : /*
810 : : * We did not release the target buffer, and otherBuffer is valid,
811 : : * need to lock the other buffer. It's guaranteed to be of a lower
812 : : * page number than the new page. To conform with the deadlock
813 : : * prevent rules, we ought to lock otherBuffer first, but that would
814 : : * give other backends a chance to put tuples on our page. To reduce
815 : : * the likelihood of that, attempt to lock the other buffer
816 : : * conditionally, that's very likely to work.
817 : : *
818 : : * Alternatively, we could acquire the lock on otherBuffer before
819 : : * extending the relation, but that'd require holding the lock while
820 : : * performing IO, which seems worse than an unlikely retry.
821 : : */
822 : : Assert(otherBuffer != buffer);
823 : : Assert(targetBlock > otherBlock);
824 : :
825 [ - + ]: 12623 : if (unlikely(!ConditionalLockBuffer(otherBuffer)))
826 : : {
827 : 0 : unlockedTargetBuffer = true;
828 : 0 : LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
829 : 0 : LockBuffer(otherBuffer, BUFFER_LOCK_EXCLUSIVE);
830 : 0 : LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
831 : : }
832 : 12623 : recheckVmPins = true;
833 : : }
834 : :
835 : : /*
836 : : * If one of the buffers was unlocked (always the case if otherBuffer is
837 : : * valid), it's possible, although unlikely, that an all-visible flag
838 : : * became set. We can use GetVisibilityMapPins to deal with that. It's
839 : : * possible that GetVisibilityMapPins() might need to temporarily release
840 : : * buffer locks, in which case we'll need to check if there's still enough
841 : : * space on the page below.
842 : : */
843 [ + + ]: 153068 : if (recheckVmPins)
844 : : {
845 [ - + ]: 13455 : if (GetVisibilityMapPins(relation, otherBuffer, buffer,
846 : : otherBlock, targetBlock, vmbuffer_other,
847 : : vmbuffer))
848 : 0 : unlockedTargetBuffer = true;
849 : : }
850 : :
851 : : /*
852 : : * If the target buffer was temporarily unlocked since the relation
853 : : * extension, it's possible, although unlikely, that all the space on the
854 : : * page was already used. If so, we just retry from the start. If we
855 : : * didn't unlock, something has gone wrong if there's not enough space -
856 : : * the test at the top should have prevented reaching this case.
857 : : */
858 : 153068 : pageFreeSpace = PageGetHeapFreeSpace(page);
859 [ - + ]: 153068 : if (len > pageFreeSpace)
860 : : {
861 [ # # ]: 0 : if (unlockedTargetBuffer)
862 : : {
863 [ # # ]: 0 : if (otherBuffer != InvalidBuffer)
864 : 0 : LockBuffer(otherBuffer, BUFFER_LOCK_UNLOCK);
865 : 0 : UnlockReleaseBuffer(buffer);
866 : :
867 : 0 : goto loop;
868 : : }
869 [ # # ]: 0 : elog(PANIC, "tuple is too big: size %zu", len);
870 : : }
871 : :
872 : : /*
873 : : * Remember the new page as our target for future insertions.
874 : : *
875 : : * XXX should we enter the new page into the free space map immediately,
876 : : * or just keep it for this backend's exclusive use in the short run
877 : : * (until VACUUM sees it)? Seems to depend on whether you expect the
878 : : * current backend to make more insertions or not, which is probably a
879 : : * good bet most of the time. So for now, don't add it to FSM yet.
880 : : */
881 : 153068 : RelationSetTargetBlock(relation, targetBlock);
882 : :
883 : 153068 : return buffer;
884 : : }
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