Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * heapam.h
4 : * POSTGRES heap access method definitions.
5 : *
6 : *
7 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
8 : * Portions Copyright (c) 1994, Regents of the University of California
9 : *
10 : * src/include/access/heapam.h
11 : *
12 : *-------------------------------------------------------------------------
13 : */
14 : #ifndef HEAPAM_H
15 : #define HEAPAM_H
16 :
17 : #include "access/heapam_xlog.h"
18 : #include "access/relation.h" /* for backward compatibility */
19 : #include "access/relscan.h"
20 : #include "access/sdir.h"
21 : #include "access/skey.h"
22 : #include "access/table.h" /* for backward compatibility */
23 : #include "access/tableam.h"
24 : #include "commands/vacuum.h"
25 : #include "nodes/lockoptions.h"
26 : #include "nodes/primnodes.h"
27 : #include "storage/bufpage.h"
28 : #include "storage/dsm.h"
29 : #include "storage/lockdefs.h"
30 : #include "storage/read_stream.h"
31 : #include "storage/shm_toc.h"
32 : #include "utils/relcache.h"
33 : #include "utils/snapshot.h"
34 :
35 :
36 : /* "options" flag bits for heap_insert */
37 : #define HEAP_INSERT_SKIP_FSM TABLE_INSERT_SKIP_FSM
38 : #define HEAP_INSERT_FROZEN TABLE_INSERT_FROZEN
39 : #define HEAP_INSERT_NO_LOGICAL TABLE_INSERT_NO_LOGICAL
40 : #define HEAP_INSERT_SPECULATIVE 0x0010
41 :
42 : /* "options" flag bits for heap_page_prune_and_freeze */
43 : #define HEAP_PAGE_PRUNE_MARK_UNUSED_NOW (1 << 0)
44 : #define HEAP_PAGE_PRUNE_FREEZE (1 << 1)
45 :
46 : typedef struct BulkInsertStateData *BulkInsertState;
47 : typedef struct GlobalVisState GlobalVisState;
48 : typedef struct TupleTableSlot TupleTableSlot;
49 : struct VacuumCutoffs;
50 :
51 : #define MaxLockTupleMode LockTupleExclusive
52 :
53 : /*
54 : * Descriptor for heap table scans.
55 : */
56 : typedef struct HeapScanDescData
57 : {
58 : TableScanDescData rs_base; /* AM independent part of the descriptor */
59 :
60 : /* state set up at initscan time */
61 : BlockNumber rs_nblocks; /* total number of blocks in rel */
62 : BlockNumber rs_startblock; /* block # to start at */
63 : BlockNumber rs_numblocks; /* max number of blocks to scan */
64 : /* rs_numblocks is usually InvalidBlockNumber, meaning "scan whole rel" */
65 :
66 : /* scan current state */
67 : bool rs_inited; /* false = scan not init'd yet */
68 : OffsetNumber rs_coffset; /* current offset # in non-page-at-a-time mode */
69 : BlockNumber rs_cblock; /* current block # in scan, if any */
70 : Buffer rs_cbuf; /* current buffer in scan, if any */
71 : /* NB: if rs_cbuf is not InvalidBuffer, we hold a pin on that buffer */
72 :
73 : BufferAccessStrategy rs_strategy; /* access strategy for reads */
74 :
75 : HeapTupleData rs_ctup; /* current tuple in scan, if any */
76 :
77 : /* For scans that stream reads */
78 : ReadStream *rs_read_stream;
79 :
80 : /*
81 : * For sequential scans and TID range scans to stream reads. The read
82 : * stream is allocated at the beginning of the scan and reset on rescan or
83 : * when the scan direction changes. The scan direction is saved each time
84 : * a new page is requested. If the scan direction changes from one page to
85 : * the next, the read stream releases all previously pinned buffers and
86 : * resets the prefetch block.
87 : */
88 : ScanDirection rs_dir;
89 : BlockNumber rs_prefetch_block;
90 :
91 : /*
92 : * For parallel scans to store page allocation data. NULL when not
93 : * performing a parallel scan.
94 : */
95 : ParallelBlockTableScanWorkerData *rs_parallelworkerdata;
96 :
97 : /* these fields only used in page-at-a-time mode and for bitmap scans */
98 : uint32 rs_cindex; /* current tuple's index in vistuples */
99 : uint32 rs_ntuples; /* number of visible tuples on page */
100 : OffsetNumber rs_vistuples[MaxHeapTuplesPerPage]; /* their offsets */
101 : } HeapScanDescData;
102 : typedef struct HeapScanDescData *HeapScanDesc;
103 :
104 : typedef struct BitmapHeapScanDescData
105 : {
106 : HeapScanDescData rs_heap_base;
107 :
108 : /* Holds no data */
109 : } BitmapHeapScanDescData;
110 : typedef struct BitmapHeapScanDescData *BitmapHeapScanDesc;
111 :
112 : /*
113 : * Descriptor for fetches from heap via an index.
114 : */
115 : typedef struct IndexFetchHeapData
116 : {
117 : IndexFetchTableData xs_base; /* AM independent part of the descriptor */
118 :
119 : Buffer xs_cbuf; /* current heap buffer in scan, if any */
120 : /* NB: if xs_cbuf is not InvalidBuffer, we hold a pin on that buffer */
121 : } IndexFetchHeapData;
122 :
123 : /* Result codes for HeapTupleSatisfiesVacuum */
124 : typedef enum
125 : {
126 : HEAPTUPLE_DEAD, /* tuple is dead and deletable */
127 : HEAPTUPLE_LIVE, /* tuple is live (committed, no deleter) */
128 : HEAPTUPLE_RECENTLY_DEAD, /* tuple is dead, but not deletable yet */
129 : HEAPTUPLE_INSERT_IN_PROGRESS, /* inserting xact is still in progress */
130 : HEAPTUPLE_DELETE_IN_PROGRESS, /* deleting xact is still in progress */
131 : } HTSV_Result;
132 :
133 : /*
134 : * heap_prepare_freeze_tuple may request that heap_freeze_execute_prepared
135 : * check any tuple's to-be-frozen xmin and/or xmax status using pg_xact
136 : */
137 : #define HEAP_FREEZE_CHECK_XMIN_COMMITTED 0x01
138 : #define HEAP_FREEZE_CHECK_XMAX_ABORTED 0x02
139 :
140 : /* heap_prepare_freeze_tuple state describing how to freeze a tuple */
141 : typedef struct HeapTupleFreeze
142 : {
143 : /* Fields describing how to process tuple */
144 : TransactionId xmax;
145 : uint16 t_infomask2;
146 : uint16 t_infomask;
147 : uint8 frzflags;
148 :
149 : /* xmin/xmax check flags */
150 : uint8 checkflags;
151 : /* Page offset number for tuple */
152 : OffsetNumber offset;
153 : } HeapTupleFreeze;
154 :
155 : /*
156 : * State used by VACUUM to track the details of freezing all eligible tuples
157 : * on a given heap page.
158 : *
159 : * VACUUM prepares freeze plans for each page via heap_prepare_freeze_tuple
160 : * calls (every tuple with storage gets its own call). This page-level freeze
161 : * state is updated across each call, which ultimately determines whether or
162 : * not freezing the page is required.
163 : *
164 : * Aside from the basic question of whether or not freezing will go ahead, the
165 : * state also tracks the oldest extant XID/MXID in the table as a whole, for
166 : * the purposes of advancing relfrozenxid/relminmxid values in pg_class later
167 : * on. Each heap_prepare_freeze_tuple call pushes NewRelfrozenXid and/or
168 : * NewRelminMxid back as required to avoid unsafe final pg_class values. Any
169 : * and all unfrozen XIDs or MXIDs that remain after VACUUM finishes _must_
170 : * have values >= the final relfrozenxid/relminmxid values in pg_class. This
171 : * includes XIDs that remain as MultiXact members from any tuple's xmax.
172 : *
173 : * When 'freeze_required' flag isn't set after all tuples are examined, the
174 : * final choice on freezing is made by vacuumlazy.c. It can decide to trigger
175 : * freezing based on whatever criteria it deems appropriate. However, it is
176 : * recommended that vacuumlazy.c avoid early freezing when freezing does not
177 : * enable setting the target page all-frozen in the visibility map afterwards.
178 : */
179 : typedef struct HeapPageFreeze
180 : {
181 : /* Is heap_prepare_freeze_tuple caller required to freeze page? */
182 : bool freeze_required;
183 :
184 : /*
185 : * "Freeze" NewRelfrozenXid/NewRelminMxid trackers.
186 : *
187 : * Trackers used when heap_freeze_execute_prepared freezes, or when there
188 : * are zero freeze plans for a page. It is always valid for vacuumlazy.c
189 : * to freeze any page, by definition. This even includes pages that have
190 : * no tuples with storage to consider in the first place. That way the
191 : * 'totally_frozen' results from heap_prepare_freeze_tuple can always be
192 : * used in the same way, even when no freeze plans need to be executed to
193 : * "freeze the page". Only the "freeze" path needs to consider the need
194 : * to set pages all-frozen in the visibility map under this scheme.
195 : *
196 : * When we freeze a page, we generally freeze all XIDs < OldestXmin, only
197 : * leaving behind XIDs that are ineligible for freezing, if any. And so
198 : * you might wonder why these trackers are necessary at all; why should
199 : * _any_ page that VACUUM freezes _ever_ be left with XIDs/MXIDs that
200 : * ratchet back the top-level NewRelfrozenXid/NewRelminMxid trackers?
201 : *
202 : * It is useful to use a definition of "freeze the page" that does not
203 : * overspecify how MultiXacts are affected. heap_prepare_freeze_tuple
204 : * generally prefers to remove Multis eagerly, but lazy processing is used
205 : * in cases where laziness allows VACUUM to avoid allocating a new Multi.
206 : * The "freeze the page" trackers enable this flexibility.
207 : */
208 : TransactionId FreezePageRelfrozenXid;
209 : MultiXactId FreezePageRelminMxid;
210 :
211 : /*
212 : * "No freeze" NewRelfrozenXid/NewRelminMxid trackers.
213 : *
214 : * These trackers are maintained in the same way as the trackers used when
215 : * VACUUM scans a page that isn't cleanup locked. Both code paths are
216 : * based on the same general idea (do less work for this page during the
217 : * ongoing VACUUM, at the cost of having to accept older final values).
218 : */
219 : TransactionId NoFreezePageRelfrozenXid;
220 : MultiXactId NoFreezePageRelminMxid;
221 :
222 : } HeapPageFreeze;
223 :
224 :
225 : /* 'reason' codes for heap_page_prune_and_freeze() */
226 : typedef enum
227 : {
228 : PRUNE_ON_ACCESS, /* on-access pruning */
229 : PRUNE_VACUUM_SCAN, /* VACUUM 1st heap pass */
230 : PRUNE_VACUUM_CLEANUP, /* VACUUM 2nd heap pass */
231 : } PruneReason;
232 :
233 : /*
234 : * Input parameters to heap_page_prune_and_freeze()
235 : */
236 : typedef struct PruneFreezeParams
237 : {
238 : Relation relation; /* relation containing buffer to be pruned */
239 : Buffer buffer; /* buffer to be pruned */
240 :
241 : /*
242 : * The reason pruning was performed. It is used to set the WAL record
243 : * opcode which is used for debugging and analysis purposes.
244 : */
245 : PruneReason reason;
246 :
247 : /*
248 : * Contains flag bits:
249 : *
250 : * HEAP_PAGE_PRUNE_MARK_UNUSED_NOW indicates that dead items can be set
251 : * LP_UNUSED during pruning.
252 : *
253 : * HEAP_PAGE_PRUNE_FREEZE indicates that we will also freeze tuples, and
254 : * will return 'all_visible', 'all_frozen' flags to the caller.
255 : */
256 : int options;
257 :
258 : /*
259 : * vistest is used to distinguish whether tuples are DEAD or RECENTLY_DEAD
260 : * (see heap_prune_satisfies_vacuum).
261 : */
262 : GlobalVisState *vistest;
263 :
264 : /*
265 : * Contains the cutoffs used for freezing. They are required if the
266 : * HEAP_PAGE_PRUNE_FREEZE option is set. cutoffs->OldestXmin is also used
267 : * to determine if dead tuples are HEAPTUPLE_RECENTLY_DEAD or
268 : * HEAPTUPLE_DEAD. Currently only vacuum passes in cutoffs. Vacuum
269 : * calculates them once, at the beginning of vacuuming the relation.
270 : */
271 : struct VacuumCutoffs *cutoffs;
272 : } PruneFreezeParams;
273 :
274 : /*
275 : * Per-page state returned by heap_page_prune_and_freeze()
276 : */
277 : typedef struct PruneFreezeResult
278 : {
279 : int ndeleted; /* Number of tuples deleted from the page */
280 : int nnewlpdead; /* Number of newly LP_DEAD items */
281 : int nfrozen; /* Number of tuples we froze */
282 :
283 : /* Number of live and recently dead tuples on the page, after pruning */
284 : int live_tuples;
285 : int recently_dead_tuples;
286 :
287 : /*
288 : * all_visible and all_frozen indicate if the all-visible and all-frozen
289 : * bits in the visibility map can be set for this page, after pruning.
290 : *
291 : * vm_conflict_horizon is the newest xmin of live tuples on the page. The
292 : * caller can use it as the conflict horizon when setting the VM bits. It
293 : * is only valid if we froze some tuples (nfrozen > 0), and all_frozen is
294 : * true.
295 : *
296 : * These are only set if the HEAP_PRUNE_FREEZE option is set.
297 : */
298 : bool all_visible;
299 : bool all_frozen;
300 : TransactionId vm_conflict_horizon;
301 :
302 : /*
303 : * Whether or not the page makes rel truncation unsafe. This is set to
304 : * 'true', even if the page contains LP_DEAD items. VACUUM will remove
305 : * them before attempting to truncate.
306 : */
307 : bool hastup;
308 :
309 : /*
310 : * LP_DEAD items on the page after pruning. Includes existing LP_DEAD
311 : * items.
312 : */
313 : int lpdead_items;
314 : OffsetNumber deadoffsets[MaxHeapTuplesPerPage];
315 : } PruneFreezeResult;
316 :
317 :
318 : /* ----------------
319 : * function prototypes for heap access method
320 : *
321 : * heap_create, heap_create_with_catalog, and heap_drop_with_catalog
322 : * are declared in catalog/heap.h
323 : * ----------------
324 : */
325 :
326 :
327 : extern TableScanDesc heap_beginscan(Relation relation, Snapshot snapshot,
328 : int nkeys, ScanKey key,
329 : ParallelTableScanDesc parallel_scan,
330 : uint32 flags);
331 : extern void heap_setscanlimits(TableScanDesc sscan, BlockNumber startBlk,
332 : BlockNumber numBlks);
333 : extern void heap_prepare_pagescan(TableScanDesc sscan);
334 : extern void heap_rescan(TableScanDesc sscan, ScanKey key, bool set_params,
335 : bool allow_strat, bool allow_sync, bool allow_pagemode);
336 : extern void heap_endscan(TableScanDesc sscan);
337 : extern HeapTuple heap_getnext(TableScanDesc sscan, ScanDirection direction);
338 : extern bool heap_getnextslot(TableScanDesc sscan,
339 : ScanDirection direction, TupleTableSlot *slot);
340 : extern void heap_set_tidrange(TableScanDesc sscan, ItemPointer mintid,
341 : ItemPointer maxtid);
342 : extern bool heap_getnextslot_tidrange(TableScanDesc sscan,
343 : ScanDirection direction,
344 : TupleTableSlot *slot);
345 : extern bool heap_fetch(Relation relation, Snapshot snapshot,
346 : HeapTuple tuple, Buffer *userbuf, bool keep_buf);
347 : extern bool heap_hot_search_buffer(ItemPointer tid, Relation relation,
348 : Buffer buffer, Snapshot snapshot, HeapTuple heapTuple,
349 : bool *all_dead, bool first_call);
350 :
351 : extern void heap_get_latest_tid(TableScanDesc sscan, ItemPointer tid);
352 :
353 : extern BulkInsertState GetBulkInsertState(void);
354 : extern void FreeBulkInsertState(BulkInsertState);
355 : extern void ReleaseBulkInsertStatePin(BulkInsertState bistate);
356 :
357 : extern void heap_insert(Relation relation, HeapTuple tup, CommandId cid,
358 : int options, BulkInsertState bistate);
359 : extern void heap_multi_insert(Relation relation, TupleTableSlot **slots,
360 : int ntuples, CommandId cid, int options,
361 : BulkInsertState bistate);
362 : extern TM_Result heap_delete(Relation relation, const ItemPointerData *tid,
363 : CommandId cid, Snapshot crosscheck, bool wait,
364 : TM_FailureData *tmfd, bool changingPart);
365 : extern void heap_finish_speculative(Relation relation, const ItemPointerData *tid);
366 : extern void heap_abort_speculative(Relation relation, const ItemPointerData *tid);
367 : extern TM_Result heap_update(Relation relation, const ItemPointerData *otid,
368 : HeapTuple newtup,
369 : CommandId cid, Snapshot crosscheck, bool wait,
370 : TM_FailureData *tmfd, LockTupleMode *lockmode,
371 : TU_UpdateIndexes *update_indexes);
372 : extern TM_Result heap_lock_tuple(Relation relation, HeapTuple tuple,
373 : CommandId cid, LockTupleMode mode, LockWaitPolicy wait_policy,
374 : bool follow_updates,
375 : Buffer *buffer, TM_FailureData *tmfd);
376 :
377 : extern bool heap_inplace_lock(Relation relation,
378 : HeapTuple oldtup_ptr, Buffer buffer,
379 : void (*release_callback) (void *), void *arg);
380 : extern void heap_inplace_update_and_unlock(Relation relation,
381 : HeapTuple oldtup, HeapTuple tuple,
382 : Buffer buffer);
383 : extern void heap_inplace_unlock(Relation relation,
384 : HeapTuple oldtup, Buffer buffer);
385 : extern bool heap_prepare_freeze_tuple(HeapTupleHeader tuple,
386 : const struct VacuumCutoffs *cutoffs,
387 : HeapPageFreeze *pagefrz,
388 : HeapTupleFreeze *frz, bool *totally_frozen);
389 :
390 : extern void heap_pre_freeze_checks(Buffer buffer,
391 : HeapTupleFreeze *tuples, int ntuples);
392 : extern void heap_freeze_prepared_tuples(Buffer buffer,
393 : HeapTupleFreeze *tuples, int ntuples);
394 : extern bool heap_freeze_tuple(HeapTupleHeader tuple,
395 : TransactionId relfrozenxid, TransactionId relminmxid,
396 : TransactionId FreezeLimit, TransactionId MultiXactCutoff);
397 : extern bool heap_tuple_should_freeze(HeapTupleHeader tuple,
398 : const struct VacuumCutoffs *cutoffs,
399 : TransactionId *NoFreezePageRelfrozenXid,
400 : MultiXactId *NoFreezePageRelminMxid);
401 : extern bool heap_tuple_needs_eventual_freeze(HeapTupleHeader tuple);
402 :
403 : extern void simple_heap_insert(Relation relation, HeapTuple tup);
404 : extern void simple_heap_delete(Relation relation, const ItemPointerData *tid);
405 : extern void simple_heap_update(Relation relation, const ItemPointerData *otid,
406 : HeapTuple tup, TU_UpdateIndexes *update_indexes);
407 :
408 : extern TransactionId heap_index_delete_tuples(Relation rel,
409 : TM_IndexDeleteOp *delstate);
410 :
411 : /* in heap/pruneheap.c */
412 : extern void heap_page_prune_opt(Relation relation, Buffer buffer);
413 : extern void heap_page_prune_and_freeze(PruneFreezeParams *params,
414 : PruneFreezeResult *presult,
415 : OffsetNumber *off_loc,
416 : TransactionId *new_relfrozen_xid,
417 : MultiXactId *new_relmin_mxid);
418 : extern void heap_page_prune_execute(Buffer buffer, bool lp_truncate_only,
419 : OffsetNumber *redirected, int nredirected,
420 : OffsetNumber *nowdead, int ndead,
421 : OffsetNumber *nowunused, int nunused);
422 : extern void heap_get_root_tuples(Page page, OffsetNumber *root_offsets);
423 : extern void log_heap_prune_and_freeze(Relation relation, Buffer buffer,
424 : Buffer vmbuffer, uint8 vmflags,
425 : TransactionId conflict_xid,
426 : bool cleanup_lock,
427 : PruneReason reason,
428 : HeapTupleFreeze *frozen, int nfrozen,
429 : OffsetNumber *redirected, int nredirected,
430 : OffsetNumber *dead, int ndead,
431 : OffsetNumber *unused, int nunused);
432 :
433 : /* in heap/vacuumlazy.c */
434 : extern void heap_vacuum_rel(Relation rel,
435 : const VacuumParams params, BufferAccessStrategy bstrategy);
436 :
437 : /* in heap/heapam_visibility.c */
438 : extern bool HeapTupleSatisfiesVisibility(HeapTuple htup, Snapshot snapshot,
439 : Buffer buffer);
440 : extern TM_Result HeapTupleSatisfiesUpdate(HeapTuple htup, CommandId curcid,
441 : Buffer buffer);
442 : extern HTSV_Result HeapTupleSatisfiesVacuum(HeapTuple htup, TransactionId OldestXmin,
443 : Buffer buffer);
444 : extern HTSV_Result HeapTupleSatisfiesVacuumHorizon(HeapTuple htup, Buffer buffer,
445 : TransactionId *dead_after);
446 : extern void HeapTupleSetHintBits(HeapTupleHeader tuple, Buffer buffer,
447 : uint16 infomask, TransactionId xid);
448 : extern bool HeapTupleHeaderIsOnlyLocked(HeapTupleHeader tuple);
449 : extern bool HeapTupleIsSurelyDead(HeapTuple htup,
450 : GlobalVisState *vistest);
451 :
452 : /*
453 : * To avoid leaking too much knowledge about reorderbuffer implementation
454 : * details this is implemented in reorderbuffer.c not heapam_visibility.c
455 : */
456 : struct HTAB;
457 : extern bool ResolveCminCmaxDuringDecoding(struct HTAB *tuplecid_data,
458 : Snapshot snapshot,
459 : HeapTuple htup,
460 : Buffer buffer,
461 : CommandId *cmin, CommandId *cmax);
462 : extern void HeapCheckForSerializableConflictOut(bool visible, Relation relation, HeapTuple tuple,
463 : Buffer buffer, Snapshot snapshot);
464 :
465 : /*
466 : * heap_execute_freeze_tuple
467 : * Execute the prepared freezing of a tuple with caller's freeze plan.
468 : *
469 : * Caller is responsible for ensuring that no other backend can access the
470 : * storage underlying this tuple, either by holding an exclusive lock on the
471 : * buffer containing it (which is what lazy VACUUM does), or by having it be
472 : * in private storage (which is what CLUSTER and friends do).
473 : */
474 : static inline void
475 2515242 : heap_execute_freeze_tuple(HeapTupleHeader tuple, HeapTupleFreeze *frz)
476 : {
477 2515242 : HeapTupleHeaderSetXmax(tuple, frz->xmax);
478 :
479 2515242 : if (frz->frzflags & XLH_FREEZE_XVAC)
480 0 : HeapTupleHeaderSetXvac(tuple, FrozenTransactionId);
481 :
482 2515242 : if (frz->frzflags & XLH_INVALID_XVAC)
483 0 : HeapTupleHeaderSetXvac(tuple, InvalidTransactionId);
484 :
485 2515242 : tuple->t_infomask = frz->t_infomask;
486 2515242 : tuple->t_infomask2 = frz->t_infomask2;
487 2515242 : }
488 :
489 : #endif /* HEAPAM_H */
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