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 : struct TupleTableSlot;
48 : struct VacuumCutoffs;
49 :
50 : #define MaxLockTupleMode LockTupleExclusive
51 :
52 : /*
53 : * Descriptor for heap table scans.
54 : */
55 : typedef struct HeapScanDescData
56 : {
57 : TableScanDescData rs_base; /* AM independent part of the descriptor */
58 :
59 : /* state set up at initscan time */
60 : BlockNumber rs_nblocks; /* total number of blocks in rel */
61 : BlockNumber rs_startblock; /* block # to start at */
62 : BlockNumber rs_numblocks; /* max number of blocks to scan */
63 : /* rs_numblocks is usually InvalidBlockNumber, meaning "scan whole rel" */
64 :
65 : /* scan current state */
66 : bool rs_inited; /* false = scan not init'd yet */
67 : OffsetNumber rs_coffset; /* current offset # in non-page-at-a-time mode */
68 : BlockNumber rs_cblock; /* current block # in scan, if any */
69 : Buffer rs_cbuf; /* current buffer in scan, if any */
70 : /* NB: if rs_cbuf is not InvalidBuffer, we hold a pin on that buffer */
71 :
72 : BufferAccessStrategy rs_strategy; /* access strategy for reads */
73 :
74 : HeapTupleData rs_ctup; /* current tuple in scan, if any */
75 :
76 : /* For scans that stream reads */
77 : ReadStream *rs_read_stream;
78 :
79 : /*
80 : * For sequential scans and TID range scans to stream reads. The read
81 : * stream is allocated at the beginning of the scan and reset on rescan or
82 : * when the scan direction changes. The scan direction is saved each time
83 : * a new page is requested. If the scan direction changes from one page to
84 : * the next, the read stream releases all previously pinned buffers and
85 : * resets the prefetch block.
86 : */
87 : ScanDirection rs_dir;
88 : BlockNumber rs_prefetch_block;
89 :
90 : /*
91 : * For parallel scans to store page allocation data. NULL when not
92 : * performing a parallel scan.
93 : */
94 : ParallelBlockTableScanWorkerData *rs_parallelworkerdata;
95 :
96 : /* these fields only used in page-at-a-time mode and for bitmap scans */
97 : uint32 rs_cindex; /* current tuple's index in vistuples */
98 : uint32 rs_ntuples; /* number of visible tuples on page */
99 : OffsetNumber rs_vistuples[MaxHeapTuplesPerPage]; /* their offsets */
100 : } HeapScanDescData;
101 : typedef struct HeapScanDescData *HeapScanDesc;
102 :
103 : typedef struct BitmapHeapScanDescData
104 : {
105 : HeapScanDescData rs_heap_base;
106 :
107 : /* Holds no data */
108 : } BitmapHeapScanDescData;
109 : typedef struct BitmapHeapScanDescData *BitmapHeapScanDesc;
110 :
111 : /*
112 : * Descriptor for fetches from heap via an index.
113 : */
114 : typedef struct IndexFetchHeapData
115 : {
116 : IndexFetchTableData xs_base; /* AM independent part of the descriptor */
117 :
118 : Buffer xs_cbuf; /* current heap buffer in scan, if any */
119 : /* NB: if xs_cbuf is not InvalidBuffer, we hold a pin on that buffer */
120 : } IndexFetchHeapData;
121 :
122 : /* Result codes for HeapTupleSatisfiesVacuum */
123 : typedef enum
124 : {
125 : HEAPTUPLE_DEAD, /* tuple is dead and deletable */
126 : HEAPTUPLE_LIVE, /* tuple is live (committed, no deleter) */
127 : HEAPTUPLE_RECENTLY_DEAD, /* tuple is dead, but not deletable yet */
128 : HEAPTUPLE_INSERT_IN_PROGRESS, /* inserting xact is still in progress */
129 : HEAPTUPLE_DELETE_IN_PROGRESS, /* deleting xact is still in progress */
130 : } HTSV_Result;
131 :
132 : /*
133 : * heap_prepare_freeze_tuple may request that heap_freeze_execute_prepared
134 : * check any tuple's to-be-frozen xmin and/or xmax status using pg_xact
135 : */
136 : #define HEAP_FREEZE_CHECK_XMIN_COMMITTED 0x01
137 : #define HEAP_FREEZE_CHECK_XMAX_ABORTED 0x02
138 :
139 : /* heap_prepare_freeze_tuple state describing how to freeze a tuple */
140 : typedef struct HeapTupleFreeze
141 : {
142 : /* Fields describing how to process tuple */
143 : TransactionId xmax;
144 : uint16 t_infomask2;
145 : uint16 t_infomask;
146 : uint8 frzflags;
147 :
148 : /* xmin/xmax check flags */
149 : uint8 checkflags;
150 : /* Page offset number for tuple */
151 : OffsetNumber offset;
152 : } HeapTupleFreeze;
153 :
154 : /*
155 : * State used by VACUUM to track the details of freezing all eligible tuples
156 : * on a given heap page.
157 : *
158 : * VACUUM prepares freeze plans for each page via heap_prepare_freeze_tuple
159 : * calls (every tuple with storage gets its own call). This page-level freeze
160 : * state is updated across each call, which ultimately determines whether or
161 : * not freezing the page is required.
162 : *
163 : * Aside from the basic question of whether or not freezing will go ahead, the
164 : * state also tracks the oldest extant XID/MXID in the table as a whole, for
165 : * the purposes of advancing relfrozenxid/relminmxid values in pg_class later
166 : * on. Each heap_prepare_freeze_tuple call pushes NewRelfrozenXid and/or
167 : * NewRelminMxid back as required to avoid unsafe final pg_class values. Any
168 : * and all unfrozen XIDs or MXIDs that remain after VACUUM finishes _must_
169 : * have values >= the final relfrozenxid/relminmxid values in pg_class. This
170 : * includes XIDs that remain as MultiXact members from any tuple's xmax.
171 : *
172 : * When 'freeze_required' flag isn't set after all tuples are examined, the
173 : * final choice on freezing is made by vacuumlazy.c. It can decide to trigger
174 : * freezing based on whatever criteria it deems appropriate. However, it is
175 : * recommended that vacuumlazy.c avoid early freezing when freezing does not
176 : * enable setting the target page all-frozen in the visibility map afterwards.
177 : */
178 : typedef struct HeapPageFreeze
179 : {
180 : /* Is heap_prepare_freeze_tuple caller required to freeze page? */
181 : bool freeze_required;
182 :
183 : /*
184 : * "Freeze" NewRelfrozenXid/NewRelminMxid trackers.
185 : *
186 : * Trackers used when heap_freeze_execute_prepared freezes, or when there
187 : * are zero freeze plans for a page. It is always valid for vacuumlazy.c
188 : * to freeze any page, by definition. This even includes pages that have
189 : * no tuples with storage to consider in the first place. That way the
190 : * 'totally_frozen' results from heap_prepare_freeze_tuple can always be
191 : * used in the same way, even when no freeze plans need to be executed to
192 : * "freeze the page". Only the "freeze" path needs to consider the need
193 : * to set pages all-frozen in the visibility map under this scheme.
194 : *
195 : * When we freeze a page, we generally freeze all XIDs < OldestXmin, only
196 : * leaving behind XIDs that are ineligible for freezing, if any. And so
197 : * you might wonder why these trackers are necessary at all; why should
198 : * _any_ page that VACUUM freezes _ever_ be left with XIDs/MXIDs that
199 : * ratchet back the top-level NewRelfrozenXid/NewRelminMxid trackers?
200 : *
201 : * It is useful to use a definition of "freeze the page" that does not
202 : * overspecify how MultiXacts are affected. heap_prepare_freeze_tuple
203 : * generally prefers to remove Multis eagerly, but lazy processing is used
204 : * in cases where laziness allows VACUUM to avoid allocating a new Multi.
205 : * The "freeze the page" trackers enable this flexibility.
206 : */
207 : TransactionId FreezePageRelfrozenXid;
208 : MultiXactId FreezePageRelminMxid;
209 :
210 : /*
211 : * "No freeze" NewRelfrozenXid/NewRelminMxid trackers.
212 : *
213 : * These trackers are maintained in the same way as the trackers used when
214 : * VACUUM scans a page that isn't cleanup locked. Both code paths are
215 : * based on the same general idea (do less work for this page during the
216 : * ongoing VACUUM, at the cost of having to accept older final values).
217 : */
218 : TransactionId NoFreezePageRelfrozenXid;
219 : MultiXactId NoFreezePageRelminMxid;
220 :
221 : } HeapPageFreeze;
222 :
223 : /*
224 : * Per-page state returned by heap_page_prune_and_freeze()
225 : */
226 : typedef struct PruneFreezeResult
227 : {
228 : int ndeleted; /* Number of tuples deleted from the page */
229 : int nnewlpdead; /* Number of newly LP_DEAD items */
230 : int nfrozen; /* Number of tuples we froze */
231 :
232 : /* Number of live and recently dead tuples on the page, after pruning */
233 : int live_tuples;
234 : int recently_dead_tuples;
235 :
236 : /*
237 : * all_visible and all_frozen indicate if the all-visible and all-frozen
238 : * bits in the visibility map can be set for this page, after pruning.
239 : *
240 : * vm_conflict_horizon is the newest xmin of live tuples on the page. The
241 : * caller can use it as the conflict horizon when setting the VM bits. It
242 : * is only valid if we froze some tuples (nfrozen > 0), and all_frozen is
243 : * true.
244 : *
245 : * These are only set if the HEAP_PRUNE_FREEZE option is set.
246 : */
247 : bool all_visible;
248 : bool all_frozen;
249 : TransactionId vm_conflict_horizon;
250 :
251 : /*
252 : * Whether or not the page makes rel truncation unsafe. This is set to
253 : * 'true', even if the page contains LP_DEAD items. VACUUM will remove
254 : * them before attempting to truncate.
255 : */
256 : bool hastup;
257 :
258 : /*
259 : * LP_DEAD items on the page after pruning. Includes existing LP_DEAD
260 : * items.
261 : */
262 : int lpdead_items;
263 : OffsetNumber deadoffsets[MaxHeapTuplesPerPage];
264 : } PruneFreezeResult;
265 :
266 : /* 'reason' codes for heap_page_prune_and_freeze() */
267 : typedef enum
268 : {
269 : PRUNE_ON_ACCESS, /* on-access pruning */
270 : PRUNE_VACUUM_SCAN, /* VACUUM 1st heap pass */
271 : PRUNE_VACUUM_CLEANUP, /* VACUUM 2nd heap pass */
272 : } PruneReason;
273 :
274 : /* ----------------
275 : * function prototypes for heap access method
276 : *
277 : * heap_create, heap_create_with_catalog, and heap_drop_with_catalog
278 : * are declared in catalog/heap.h
279 : * ----------------
280 : */
281 :
282 :
283 : /*
284 : * HeapScanIsValid
285 : * True iff the heap scan is valid.
286 : */
287 : #define HeapScanIsValid(scan) PointerIsValid(scan)
288 :
289 : extern TableScanDesc heap_beginscan(Relation relation, Snapshot snapshot,
290 : int nkeys, ScanKey key,
291 : ParallelTableScanDesc parallel_scan,
292 : uint32 flags);
293 : extern void heap_setscanlimits(TableScanDesc sscan, BlockNumber startBlk,
294 : BlockNumber numBlks);
295 : extern void heap_prepare_pagescan(TableScanDesc sscan);
296 : extern void heap_rescan(TableScanDesc sscan, ScanKey key, bool set_params,
297 : bool allow_strat, bool allow_sync, bool allow_pagemode);
298 : extern void heap_endscan(TableScanDesc sscan);
299 : extern HeapTuple heap_getnext(TableScanDesc sscan, ScanDirection direction);
300 : extern bool heap_getnextslot(TableScanDesc sscan,
301 : ScanDirection direction, struct TupleTableSlot *slot);
302 : extern void heap_set_tidrange(TableScanDesc sscan, ItemPointer mintid,
303 : ItemPointer maxtid);
304 : extern bool heap_getnextslot_tidrange(TableScanDesc sscan,
305 : ScanDirection direction,
306 : TupleTableSlot *slot);
307 : extern bool heap_fetch(Relation relation, Snapshot snapshot,
308 : HeapTuple tuple, Buffer *userbuf, bool keep_buf);
309 : extern bool heap_hot_search_buffer(ItemPointer tid, Relation relation,
310 : Buffer buffer, Snapshot snapshot, HeapTuple heapTuple,
311 : bool *all_dead, bool first_call);
312 :
313 : extern void heap_get_latest_tid(TableScanDesc sscan, ItemPointer tid);
314 :
315 : extern BulkInsertState GetBulkInsertState(void);
316 : extern void FreeBulkInsertState(BulkInsertState);
317 : extern void ReleaseBulkInsertStatePin(BulkInsertState bistate);
318 :
319 : extern void heap_insert(Relation relation, HeapTuple tup, CommandId cid,
320 : int options, BulkInsertState bistate);
321 : extern void heap_multi_insert(Relation relation, struct TupleTableSlot **slots,
322 : int ntuples, CommandId cid, int options,
323 : BulkInsertState bistate);
324 : extern TM_Result heap_delete(Relation relation, ItemPointer tid,
325 : CommandId cid, Snapshot crosscheck, bool wait,
326 : struct TM_FailureData *tmfd, bool changingPart);
327 : extern void heap_finish_speculative(Relation relation, ItemPointer tid);
328 : extern void heap_abort_speculative(Relation relation, ItemPointer tid);
329 : extern TM_Result heap_update(Relation relation, ItemPointer otid,
330 : HeapTuple newtup,
331 : CommandId cid, Snapshot crosscheck, bool wait,
332 : struct TM_FailureData *tmfd, LockTupleMode *lockmode,
333 : TU_UpdateIndexes *update_indexes);
334 : extern TM_Result heap_lock_tuple(Relation relation, HeapTuple tuple,
335 : CommandId cid, LockTupleMode mode, LockWaitPolicy wait_policy,
336 : bool follow_updates,
337 : Buffer *buffer, struct TM_FailureData *tmfd);
338 :
339 : extern bool heap_inplace_lock(Relation relation,
340 : HeapTuple oldtup_ptr, Buffer buffer,
341 : void (*release_callback) (void *), void *arg);
342 : extern void heap_inplace_update_and_unlock(Relation relation,
343 : HeapTuple oldtup, HeapTuple tuple,
344 : Buffer buffer);
345 : extern void heap_inplace_unlock(Relation relation,
346 : HeapTuple oldtup, Buffer buffer);
347 : extern bool heap_prepare_freeze_tuple(HeapTupleHeader tuple,
348 : const struct VacuumCutoffs *cutoffs,
349 : HeapPageFreeze *pagefrz,
350 : HeapTupleFreeze *frz, bool *totally_frozen);
351 :
352 : extern void heap_pre_freeze_checks(Buffer buffer,
353 : HeapTupleFreeze *tuples, int ntuples);
354 : extern void heap_freeze_prepared_tuples(Buffer buffer,
355 : HeapTupleFreeze *tuples, int ntuples);
356 : extern bool heap_freeze_tuple(HeapTupleHeader tuple,
357 : TransactionId relfrozenxid, TransactionId relminmxid,
358 : TransactionId FreezeLimit, TransactionId MultiXactCutoff);
359 : extern bool heap_tuple_should_freeze(HeapTupleHeader tuple,
360 : const struct VacuumCutoffs *cutoffs,
361 : TransactionId *NoFreezePageRelfrozenXid,
362 : MultiXactId *NoFreezePageRelminMxid);
363 : extern bool heap_tuple_needs_eventual_freeze(HeapTupleHeader tuple);
364 :
365 : extern void simple_heap_insert(Relation relation, HeapTuple tup);
366 : extern void simple_heap_delete(Relation relation, ItemPointer tid);
367 : extern void simple_heap_update(Relation relation, ItemPointer otid,
368 : HeapTuple tup, TU_UpdateIndexes *update_indexes);
369 :
370 : extern TransactionId heap_index_delete_tuples(Relation rel,
371 : TM_IndexDeleteOp *delstate);
372 :
373 : /* in heap/pruneheap.c */
374 : struct GlobalVisState;
375 : extern void heap_page_prune_opt(Relation relation, Buffer buffer);
376 : extern void heap_page_prune_and_freeze(Relation relation, Buffer buffer,
377 : struct GlobalVisState *vistest,
378 : int options,
379 : struct VacuumCutoffs *cutoffs,
380 : PruneFreezeResult *presult,
381 : PruneReason reason,
382 : OffsetNumber *off_loc,
383 : TransactionId *new_relfrozen_xid,
384 : MultiXactId *new_relmin_mxid);
385 : extern void heap_page_prune_execute(Buffer buffer, bool lp_truncate_only,
386 : OffsetNumber *redirected, int nredirected,
387 : OffsetNumber *nowdead, int ndead,
388 : OffsetNumber *nowunused, int nunused);
389 : extern void heap_get_root_tuples(Page page, OffsetNumber *root_offsets);
390 : extern void log_heap_prune_and_freeze(Relation relation, Buffer buffer,
391 : TransactionId conflict_xid,
392 : bool cleanup_lock,
393 : PruneReason reason,
394 : HeapTupleFreeze *frozen, int nfrozen,
395 : OffsetNumber *redirected, int nredirected,
396 : OffsetNumber *dead, int ndead,
397 : OffsetNumber *unused, int nunused);
398 :
399 : /* in heap/vacuumlazy.c */
400 : extern void heap_vacuum_rel(Relation rel,
401 : const VacuumParams params, BufferAccessStrategy bstrategy);
402 :
403 : /* in heap/heapam_visibility.c */
404 : extern bool HeapTupleSatisfiesVisibility(HeapTuple htup, Snapshot snapshot,
405 : Buffer buffer);
406 : extern TM_Result HeapTupleSatisfiesUpdate(HeapTuple htup, CommandId curcid,
407 : Buffer buffer);
408 : extern HTSV_Result HeapTupleSatisfiesVacuum(HeapTuple htup, TransactionId OldestXmin,
409 : Buffer buffer);
410 : extern HTSV_Result HeapTupleSatisfiesVacuumHorizon(HeapTuple htup, Buffer buffer,
411 : TransactionId *dead_after);
412 : extern void HeapTupleSetHintBits(HeapTupleHeader tuple, Buffer buffer,
413 : uint16 infomask, TransactionId xid);
414 : extern bool HeapTupleHeaderIsOnlyLocked(HeapTupleHeader tuple);
415 : extern bool HeapTupleIsSurelyDead(HeapTuple htup,
416 : struct GlobalVisState *vistest);
417 :
418 : /*
419 : * To avoid leaking too much knowledge about reorderbuffer implementation
420 : * details this is implemented in reorderbuffer.c not heapam_visibility.c
421 : */
422 : struct HTAB;
423 : extern bool ResolveCminCmaxDuringDecoding(struct HTAB *tuplecid_data,
424 : Snapshot snapshot,
425 : HeapTuple htup,
426 : Buffer buffer,
427 : CommandId *cmin, CommandId *cmax);
428 : extern void HeapCheckForSerializableConflictOut(bool visible, Relation relation, HeapTuple tuple,
429 : Buffer buffer, Snapshot snapshot);
430 :
431 : /*
432 : * heap_execute_freeze_tuple
433 : * Execute the prepared freezing of a tuple with caller's freeze plan.
434 : *
435 : * Caller is responsible for ensuring that no other backend can access the
436 : * storage underlying this tuple, either by holding an exclusive lock on the
437 : * buffer containing it (which is what lazy VACUUM does), or by having it be
438 : * in private storage (which is what CLUSTER and friends do).
439 : */
440 : static inline void
441 2570496 : heap_execute_freeze_tuple(HeapTupleHeader tuple, HeapTupleFreeze *frz)
442 : {
443 2570496 : HeapTupleHeaderSetXmax(tuple, frz->xmax);
444 :
445 2570496 : if (frz->frzflags & XLH_FREEZE_XVAC)
446 0 : HeapTupleHeaderSetXvac(tuple, FrozenTransactionId);
447 :
448 2570496 : if (frz->frzflags & XLH_INVALID_XVAC)
449 0 : HeapTupleHeaderSetXvac(tuple, InvalidTransactionId);
450 :
451 2570496 : tuple->t_infomask = frz->t_infomask;
452 2570496 : tuple->t_infomask2 = frz->t_infomask2;
453 2570496 : }
454 :
455 : #endif /* HEAPAM_H */
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