Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * htup_details.h
4 : * POSTGRES heap tuple header 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/htup_details.h
11 : *
12 : *-------------------------------------------------------------------------
13 : */
14 : #ifndef HTUP_DETAILS_H
15 : #define HTUP_DETAILS_H
16 :
17 : #include "access/htup.h"
18 : #include "access/transam.h"
19 : #include "access/tupdesc.h"
20 : #include "access/tupmacs.h"
21 : #include "storage/bufpage.h"
22 : #include "varatt.h"
23 :
24 : /*
25 : * MaxTupleAttributeNumber limits the number of (user) columns in a tuple.
26 : * The key limit on this value is that the size of the fixed overhead for
27 : * a tuple, plus the size of the null-values bitmap (at 1 bit per column),
28 : * plus MAXALIGN alignment, must fit into t_hoff which is uint8. On most
29 : * machines the upper limit without making t_hoff wider would be a little
30 : * over 1700. We use round numbers here and for MaxHeapAttributeNumber
31 : * so that alterations in HeapTupleHeaderData layout won't change the
32 : * supported max number of columns.
33 : */
34 : #define MaxTupleAttributeNumber 1664 /* 8 * 208 */
35 :
36 : /*
37 : * MaxHeapAttributeNumber limits the number of (user) columns in a table.
38 : * This should be somewhat less than MaxTupleAttributeNumber. It must be
39 : * at least one less, else we will fail to do UPDATEs on a maximal-width
40 : * table (because UPDATE has to form working tuples that include CTID).
41 : * In practice we want some additional daylight so that we can gracefully
42 : * support operations that add hidden "resjunk" columns, for example
43 : * SELECT * FROM wide_table ORDER BY foo, bar, baz.
44 : * In any case, depending on column data types you will likely be running
45 : * into the disk-block-based limit on overall tuple size if you have more
46 : * than a thousand or so columns. TOAST won't help.
47 : */
48 : #define MaxHeapAttributeNumber 1600 /* 8 * 200 */
49 :
50 : /*
51 : * Heap tuple header. To avoid wasting space, the fields should be
52 : * laid out in such a way as to avoid structure padding.
53 : *
54 : * Datums of composite types (row types) share the same general structure
55 : * as on-disk tuples, so that the same routines can be used to build and
56 : * examine them. However the requirements are slightly different: a Datum
57 : * does not need any transaction visibility information, and it does need
58 : * a length word and some embedded type information. We can achieve this
59 : * by overlaying the xmin/cmin/xmax/cmax/xvac fields of a heap tuple
60 : * with the fields needed in the Datum case. Typically, all tuples built
61 : * in-memory will be initialized with the Datum fields; but when a tuple is
62 : * about to be inserted in a table, the transaction fields will be filled,
63 : * overwriting the datum fields.
64 : *
65 : * The overall structure of a heap tuple looks like:
66 : * fixed fields (HeapTupleHeaderData struct)
67 : * nulls bitmap (if HEAP_HASNULL is set in t_infomask)
68 : * alignment padding (as needed to make user data MAXALIGN'd)
69 : * object ID (if HEAP_HASOID_OLD is set in t_infomask, not created
70 : * anymore)
71 : * user data fields
72 : *
73 : * We store five "virtual" fields Xmin, Cmin, Xmax, Cmax, and Xvac in three
74 : * physical fields. Xmin and Xmax are always really stored, but Cmin, Cmax
75 : * and Xvac share a field. This works because we know that Cmin and Cmax
76 : * are only interesting for the lifetime of the inserting and deleting
77 : * transaction respectively. If a tuple is inserted and deleted in the same
78 : * transaction, we store a "combo" command id that can be mapped to the real
79 : * cmin and cmax, but only by use of local state within the originating
80 : * backend. See combocid.c for more details. Meanwhile, Xvac is only set by
81 : * old-style VACUUM FULL, which does not have any command sub-structure and so
82 : * does not need either Cmin or Cmax. (This requires that old-style VACUUM
83 : * FULL never try to move a tuple whose Cmin or Cmax is still interesting,
84 : * ie, an insert-in-progress or delete-in-progress tuple.)
85 : *
86 : * A word about t_ctid: whenever a new tuple is stored on disk, its t_ctid
87 : * is initialized with its own TID (location). If the tuple is ever updated,
88 : * its t_ctid is changed to point to the replacement version of the tuple. Or
89 : * if the tuple is moved from one partition to another, due to an update of
90 : * the partition key, t_ctid is set to a special value to indicate that
91 : * (see ItemPointerSetMovedPartitions). Thus, a tuple is the latest version
92 : * of its row iff XMAX is invalid or
93 : * t_ctid points to itself (in which case, if XMAX is valid, the tuple is
94 : * either locked or deleted). One can follow the chain of t_ctid links
95 : * to find the newest version of the row, unless it was moved to a different
96 : * partition. Beware however that VACUUM might
97 : * erase the pointed-to (newer) tuple before erasing the pointing (older)
98 : * tuple. Hence, when following a t_ctid link, it is necessary to check
99 : * to see if the referenced slot is empty or contains an unrelated tuple.
100 : * Check that the referenced tuple has XMIN equal to the referencing tuple's
101 : * XMAX to verify that it is actually the descendant version and not an
102 : * unrelated tuple stored into a slot recently freed by VACUUM. If either
103 : * check fails, one may assume that there is no live descendant version.
104 : *
105 : * t_ctid is sometimes used to store a speculative insertion token, instead
106 : * of a real TID. A speculative token is set on a tuple that's being
107 : * inserted, until the inserter is sure that it wants to go ahead with the
108 : * insertion. Hence a token should only be seen on a tuple with an XMAX
109 : * that's still in-progress, or invalid/aborted. The token is replaced with
110 : * the tuple's real TID when the insertion is confirmed. One should never
111 : * see a speculative insertion token while following a chain of t_ctid links,
112 : * because they are not used on updates, only insertions.
113 : *
114 : * Following the fixed header fields, the nulls bitmap is stored (beginning
115 : * at t_bits). The bitmap is *not* stored if t_infomask shows that there
116 : * are no nulls in the tuple. If an OID field is present (as indicated by
117 : * t_infomask), then it is stored just before the user data, which begins at
118 : * the offset shown by t_hoff. Note that t_hoff must be a multiple of
119 : * MAXALIGN.
120 : */
121 :
122 : typedef struct HeapTupleFields
123 : {
124 : TransactionId t_xmin; /* inserting xact ID */
125 : TransactionId t_xmax; /* deleting or locking xact ID */
126 :
127 : union
128 : {
129 : CommandId t_cid; /* inserting or deleting command ID, or both */
130 : TransactionId t_xvac; /* old-style VACUUM FULL xact ID */
131 : } t_field3;
132 : } HeapTupleFields;
133 :
134 : typedef struct DatumTupleFields
135 : {
136 : int32 datum_len_; /* varlena header (do not touch directly!) */
137 :
138 : int32 datum_typmod; /* -1, or identifier of a record type */
139 :
140 : Oid datum_typeid; /* composite type OID, or RECORDOID */
141 :
142 : /*
143 : * datum_typeid cannot be a domain over composite, only plain composite,
144 : * even if the datum is meant as a value of a domain-over-composite type.
145 : * This is in line with the general principle that CoerceToDomain does not
146 : * change the physical representation of the base type value.
147 : *
148 : * Note: field ordering is chosen with thought that Oid might someday
149 : * widen to 64 bits.
150 : */
151 : } DatumTupleFields;
152 :
153 : struct HeapTupleHeaderData
154 : {
155 : union
156 : {
157 : HeapTupleFields t_heap;
158 : DatumTupleFields t_datum;
159 : } t_choice;
160 :
161 : ItemPointerData t_ctid; /* current TID of this or newer tuple (or a
162 : * speculative insertion token) */
163 :
164 : /* Fields below here must match MinimalTupleData! */
165 :
166 : #define FIELDNO_HEAPTUPLEHEADERDATA_INFOMASK2 2
167 : uint16 t_infomask2; /* number of attributes + various flags */
168 :
169 : #define FIELDNO_HEAPTUPLEHEADERDATA_INFOMASK 3
170 : uint16 t_infomask; /* various flag bits, see below */
171 :
172 : #define FIELDNO_HEAPTUPLEHEADERDATA_HOFF 4
173 : uint8 t_hoff; /* sizeof header incl. bitmap, padding */
174 :
175 : /* ^ - 23 bytes - ^ */
176 :
177 : #define FIELDNO_HEAPTUPLEHEADERDATA_BITS 5
178 : bits8 t_bits[FLEXIBLE_ARRAY_MEMBER]; /* bitmap of NULLs */
179 :
180 : /* MORE DATA FOLLOWS AT END OF STRUCT */
181 : };
182 :
183 : /* typedef appears in htup.h */
184 :
185 : #define SizeofHeapTupleHeader offsetof(HeapTupleHeaderData, t_bits)
186 :
187 : /*
188 : * information stored in t_infomask:
189 : */
190 : #define HEAP_HASNULL 0x0001 /* has null attribute(s) */
191 : #define HEAP_HASVARWIDTH 0x0002 /* has variable-width attribute(s) */
192 : #define HEAP_HASEXTERNAL 0x0004 /* has external stored attribute(s) */
193 : #define HEAP_HASOID_OLD 0x0008 /* has an object-id field */
194 : #define HEAP_XMAX_KEYSHR_LOCK 0x0010 /* xmax is a key-shared locker */
195 : #define HEAP_COMBOCID 0x0020 /* t_cid is a combo CID */
196 : #define HEAP_XMAX_EXCL_LOCK 0x0040 /* xmax is exclusive locker */
197 : #define HEAP_XMAX_LOCK_ONLY 0x0080 /* xmax, if valid, is only a locker */
198 :
199 : /* xmax is a shared locker */
200 : #define HEAP_XMAX_SHR_LOCK (HEAP_XMAX_EXCL_LOCK | HEAP_XMAX_KEYSHR_LOCK)
201 :
202 : #define HEAP_LOCK_MASK (HEAP_XMAX_SHR_LOCK | HEAP_XMAX_EXCL_LOCK | \
203 : HEAP_XMAX_KEYSHR_LOCK)
204 : #define HEAP_XMIN_COMMITTED 0x0100 /* t_xmin committed */
205 : #define HEAP_XMIN_INVALID 0x0200 /* t_xmin invalid/aborted */
206 : #define HEAP_XMIN_FROZEN (HEAP_XMIN_COMMITTED|HEAP_XMIN_INVALID)
207 : #define HEAP_XMAX_COMMITTED 0x0400 /* t_xmax committed */
208 : #define HEAP_XMAX_INVALID 0x0800 /* t_xmax invalid/aborted */
209 : #define HEAP_XMAX_IS_MULTI 0x1000 /* t_xmax is a MultiXactId */
210 : #define HEAP_UPDATED 0x2000 /* this is UPDATEd version of row */
211 : #define HEAP_MOVED_OFF 0x4000 /* moved to another place by pre-9.0
212 : * VACUUM FULL; kept for binary
213 : * upgrade support */
214 : #define HEAP_MOVED_IN 0x8000 /* moved from another place by pre-9.0
215 : * VACUUM FULL; kept for binary
216 : * upgrade support */
217 : #define HEAP_MOVED (HEAP_MOVED_OFF | HEAP_MOVED_IN)
218 :
219 : #define HEAP_XACT_MASK 0xFFF0 /* visibility-related bits */
220 :
221 : /*
222 : * A tuple is only locked (i.e. not updated by its Xmax) if the
223 : * HEAP_XMAX_LOCK_ONLY bit is set; or, for pg_upgrade's sake, if the Xmax is
224 : * not a multi and the EXCL_LOCK bit is set.
225 : *
226 : * See also HeapTupleHeaderIsOnlyLocked, which also checks for a possible
227 : * aborted updater transaction.
228 : */
229 : static inline bool
230 48882264 : HEAP_XMAX_IS_LOCKED_ONLY(uint16 infomask)
231 : {
232 96680432 : return (infomask & HEAP_XMAX_LOCK_ONLY) ||
233 47798168 : (infomask & (HEAP_XMAX_IS_MULTI | HEAP_LOCK_MASK)) == HEAP_XMAX_EXCL_LOCK;
234 : }
235 :
236 : /*
237 : * A tuple that has HEAP_XMAX_IS_MULTI and HEAP_XMAX_LOCK_ONLY but neither of
238 : * HEAP_XMAX_EXCL_LOCK and HEAP_XMAX_KEYSHR_LOCK must come from a tuple that was
239 : * share-locked in 9.2 or earlier and then pg_upgrade'd.
240 : *
241 : * In 9.2 and prior, HEAP_XMAX_IS_MULTI was only set when there were multiple
242 : * FOR SHARE lockers of that tuple. That set HEAP_XMAX_LOCK_ONLY (with a
243 : * different name back then) but neither of HEAP_XMAX_EXCL_LOCK and
244 : * HEAP_XMAX_KEYSHR_LOCK. That combination is no longer possible in 9.3 and
245 : * up, so if we see that combination we know for certain that the tuple was
246 : * locked in an earlier release; since all such lockers are gone (they cannot
247 : * survive through pg_upgrade), such tuples can safely be considered not
248 : * locked.
249 : *
250 : * We must not resolve such multixacts locally, because the result would be
251 : * bogus, regardless of where they stand with respect to the current valid
252 : * multixact range.
253 : */
254 : static inline bool
255 73986 : HEAP_LOCKED_UPGRADED(uint16 infomask)
256 : {
257 : return
258 76340 : (infomask & HEAP_XMAX_IS_MULTI) != 0 &&
259 76126 : (infomask & HEAP_XMAX_LOCK_ONLY) != 0 &&
260 2140 : (infomask & (HEAP_XMAX_EXCL_LOCK | HEAP_XMAX_KEYSHR_LOCK)) == 0;
261 : }
262 :
263 : /*
264 : * Use these to test whether a particular lock is applied to a tuple
265 : */
266 : static inline bool
267 198626 : HEAP_XMAX_IS_SHR_LOCKED(int16 infomask)
268 : {
269 198626 : return (infomask & HEAP_LOCK_MASK) == HEAP_XMAX_SHR_LOCK;
270 : }
271 :
272 : static inline bool
273 212206 : HEAP_XMAX_IS_EXCL_LOCKED(int16 infomask)
274 : {
275 212206 : return (infomask & HEAP_LOCK_MASK) == HEAP_XMAX_EXCL_LOCK;
276 : }
277 :
278 : static inline bool
279 210348 : HEAP_XMAX_IS_KEYSHR_LOCKED(int16 infomask)
280 : {
281 210348 : return (infomask & HEAP_LOCK_MASK) == HEAP_XMAX_KEYSHR_LOCK;
282 : }
283 :
284 : /* turn these all off when Xmax is to change */
285 : #define HEAP_XMAX_BITS (HEAP_XMAX_COMMITTED | HEAP_XMAX_INVALID | \
286 : HEAP_XMAX_IS_MULTI | HEAP_LOCK_MASK | HEAP_XMAX_LOCK_ONLY)
287 :
288 : /*
289 : * information stored in t_infomask2:
290 : */
291 : #define HEAP_NATTS_MASK 0x07FF /* 11 bits for number of attributes */
292 : /* bits 0x1800 are available */
293 : #define HEAP_KEYS_UPDATED 0x2000 /* tuple was updated and key cols
294 : * modified, or tuple deleted */
295 : #define HEAP_HOT_UPDATED 0x4000 /* tuple was HOT-updated */
296 : #define HEAP_ONLY_TUPLE 0x8000 /* this is heap-only tuple */
297 :
298 : #define HEAP2_XACT_MASK 0xE000 /* visibility-related bits */
299 :
300 : /*
301 : * HEAP_TUPLE_HAS_MATCH is a temporary flag used during hash joins. It is
302 : * only used in tuples that are in the hash table, and those don't need
303 : * any visibility information, so we can overlay it on a visibility flag
304 : * instead of using up a dedicated bit.
305 : */
306 : #define HEAP_TUPLE_HAS_MATCH HEAP_ONLY_TUPLE /* tuple has a join match */
307 :
308 : /*
309 : * HeapTupleHeader accessor functions
310 : */
311 :
312 : static bool HeapTupleHeaderXminFrozen(const HeapTupleHeaderData *tup);
313 :
314 : /*
315 : * HeapTupleHeaderGetRawXmin returns the "raw" xmin field, which is the xid
316 : * originally used to insert the tuple. However, the tuple might actually
317 : * be frozen (via HeapTupleHeaderSetXminFrozen) in which case the tuple's xmin
318 : * is visible to every snapshot. Prior to PostgreSQL 9.4, we actually changed
319 : * the xmin to FrozenTransactionId, and that value may still be encountered
320 : * on disk.
321 : */
322 : static inline TransactionId
323 277657830 : HeapTupleHeaderGetRawXmin(const HeapTupleHeaderData *tup)
324 : {
325 277657830 : return tup->t_choice.t_heap.t_xmin;
326 : }
327 :
328 : static inline TransactionId
329 102143566 : HeapTupleHeaderGetXmin(const HeapTupleHeaderData *tup)
330 : {
331 102143566 : return HeapTupleHeaderXminFrozen(tup) ?
332 102143566 : FrozenTransactionId : HeapTupleHeaderGetRawXmin(tup);
333 : }
334 :
335 : static inline void
336 22370006 : HeapTupleHeaderSetXmin(HeapTupleHeaderData *tup, TransactionId xid)
337 : {
338 22370006 : tup->t_choice.t_heap.t_xmin = xid;
339 22370006 : }
340 :
341 : static inline bool
342 269977394 : HeapTupleHeaderXminCommitted(const HeapTupleHeaderData *tup)
343 : {
344 269977394 : return (tup->t_infomask & HEAP_XMIN_COMMITTED) != 0;
345 : }
346 :
347 : static inline bool
348 65787174 : HeapTupleHeaderXminInvalid(const HeapTupleHeaderData *tup) \
349 : {
350 65787174 : return (tup->t_infomask & (HEAP_XMIN_COMMITTED | HEAP_XMIN_INVALID)) ==
351 : HEAP_XMIN_INVALID;
352 : }
353 :
354 : static inline bool
355 660467976 : HeapTupleHeaderXminFrozen(const HeapTupleHeaderData *tup)
356 : {
357 660467976 : return (tup->t_infomask & HEAP_XMIN_FROZEN) == HEAP_XMIN_FROZEN;
358 : }
359 :
360 : static inline void
361 : HeapTupleHeaderSetXminCommitted(HeapTupleHeaderData *tup)
362 : {
363 : Assert(!HeapTupleHeaderXminInvalid(tup));
364 : tup->t_infomask |= HEAP_XMIN_COMMITTED;
365 : }
366 :
367 : static inline void
368 : HeapTupleHeaderSetXminInvalid(HeapTupleHeaderData *tup)
369 : {
370 : Assert(!HeapTupleHeaderXminCommitted(tup));
371 : tup->t_infomask |= HEAP_XMIN_INVALID;
372 : }
373 :
374 : static inline void
375 206396 : HeapTupleHeaderSetXminFrozen(HeapTupleHeaderData *tup)
376 : {
377 : Assert(!HeapTupleHeaderXminInvalid(tup));
378 206396 : tup->t_infomask |= HEAP_XMIN_FROZEN;
379 206396 : }
380 :
381 : static inline TransactionId
382 130318970 : HeapTupleHeaderGetRawXmax(const HeapTupleHeaderData *tup)
383 : {
384 130318970 : return tup->t_choice.t_heap.t_xmax;
385 : }
386 :
387 : static inline void
388 26241156 : HeapTupleHeaderSetXmax(HeapTupleHeaderData *tup, TransactionId xid)
389 : {
390 26241156 : tup->t_choice.t_heap.t_xmax = xid;
391 26241156 : }
392 :
393 : #ifndef FRONTEND
394 : /*
395 : * HeapTupleHeaderGetRawXmax gets you the raw Xmax field. To find out the Xid
396 : * that updated a tuple, you might need to resolve the MultiXactId if certain
397 : * bits are set. HeapTupleHeaderGetUpdateXid checks those bits and takes care
398 : * to resolve the MultiXactId if necessary. This might involve multixact I/O,
399 : * so it should only be used if absolutely necessary.
400 : */
401 : static inline TransactionId
402 19023292 : HeapTupleHeaderGetUpdateXid(const HeapTupleHeaderData *tup)
403 : {
404 19023292 : if (!((tup)->t_infomask & HEAP_XMAX_INVALID) &&
405 17751784 : ((tup)->t_infomask & HEAP_XMAX_IS_MULTI) &&
406 376 : !((tup)->t_infomask & HEAP_XMAX_LOCK_ONLY))
407 316 : return HeapTupleGetUpdateXid(tup);
408 : else
409 19022976 : return HeapTupleHeaderGetRawXmax(tup);
410 : }
411 : #endif /* FRONTEND */
412 :
413 : /*
414 : * HeapTupleHeaderGetRawCommandId will give you what's in the header whether
415 : * it is useful or not. Most code should use HeapTupleHeaderGetCmin or
416 : * HeapTupleHeaderGetCmax instead, but note that those Assert that you can
417 : * get a legitimate result, ie you are in the originating transaction!
418 : */
419 : static inline CommandId
420 27589778 : HeapTupleHeaderGetRawCommandId(const HeapTupleHeaderData *tup)
421 : {
422 27589778 : return tup->t_choice.t_heap.t_field3.t_cid;
423 : }
424 :
425 : /* SetCmin is reasonably simple since we never need a combo CID */
426 : static inline void
427 22328278 : HeapTupleHeaderSetCmin(HeapTupleHeaderData *tup, CommandId cid)
428 : {
429 : Assert(!(tup->t_infomask & HEAP_MOVED));
430 22328278 : tup->t_choice.t_heap.t_field3.t_cid = cid;
431 22328278 : tup->t_infomask &= ~HEAP_COMBOCID;
432 22328278 : }
433 :
434 : /* SetCmax must be used after HeapTupleHeaderAdjustCmax; see combocid.c */
435 : static inline void
436 4673274 : HeapTupleHeaderSetCmax(HeapTupleHeaderData *tup, CommandId cid, bool iscombo)
437 : {
438 : Assert(!((tup)->t_infomask & HEAP_MOVED));
439 4673274 : tup->t_choice.t_heap.t_field3.t_cid = cid;
440 4673274 : if (iscombo)
441 430296 : tup->t_infomask |= HEAP_COMBOCID;
442 : else
443 4242978 : tup->t_infomask &= ~HEAP_COMBOCID;
444 4673274 : }
445 :
446 : static inline TransactionId
447 35744140 : HeapTupleHeaderGetXvac(const HeapTupleHeaderData *tup)
448 : {
449 35744140 : if (tup->t_infomask & HEAP_MOVED)
450 0 : return tup->t_choice.t_heap.t_field3.t_xvac;
451 : else
452 35744140 : return InvalidTransactionId;
453 : }
454 :
455 : static inline void
456 0 : HeapTupleHeaderSetXvac(HeapTupleHeaderData *tup, TransactionId xid)
457 : {
458 : Assert(tup->t_infomask & HEAP_MOVED);
459 0 : tup->t_choice.t_heap.t_field3.t_xvac = xid;
460 0 : }
461 :
462 : StaticAssertDecl(MaxOffsetNumber < SpecTokenOffsetNumber,
463 : "invalid speculative token constant");
464 :
465 : static inline bool
466 432686670 : HeapTupleHeaderIsSpeculative(const HeapTupleHeaderData *tup)
467 : {
468 432686670 : return ItemPointerGetOffsetNumberNoCheck(&tup->t_ctid) == SpecTokenOffsetNumber;
469 : }
470 :
471 : static inline BlockNumber
472 4 : HeapTupleHeaderGetSpeculativeToken(const HeapTupleHeaderData *tup)
473 : {
474 : Assert(HeapTupleHeaderIsSpeculative(tup));
475 4 : return ItemPointerGetBlockNumber(&tup->t_ctid);
476 : }
477 :
478 : static inline void
479 4128 : HeapTupleHeaderSetSpeculativeToken(HeapTupleHeaderData *tup, BlockNumber token)
480 : {
481 4128 : ItemPointerSet(&tup->t_ctid, token, SpecTokenOffsetNumber);
482 4128 : }
483 :
484 : static inline bool
485 47908 : HeapTupleHeaderIndicatesMovedPartitions(const HeapTupleHeaderData *tup)
486 : {
487 47908 : return ItemPointerIndicatesMovedPartitions(&tup->t_ctid);
488 : }
489 :
490 : static inline void
491 1250 : HeapTupleHeaderSetMovedPartitions(HeapTupleHeaderData *tup)
492 : {
493 1250 : ItemPointerSetMovedPartitions(&tup->t_ctid);
494 1250 : }
495 :
496 : static inline uint32
497 1672396 : HeapTupleHeaderGetDatumLength(const HeapTupleHeaderData *tup)
498 : {
499 1672396 : return VARSIZE(tup);
500 : }
501 :
502 : static inline void
503 23552224 : HeapTupleHeaderSetDatumLength(HeapTupleHeaderData *tup, uint32 len)
504 : {
505 23552224 : SET_VARSIZE(tup, len);
506 23552224 : }
507 :
508 : static inline Oid
509 1657036 : HeapTupleHeaderGetTypeId(const HeapTupleHeaderData *tup)
510 : {
511 1657036 : return tup->t_choice.t_datum.datum_typeid;
512 : }
513 :
514 : static inline void
515 23598176 : HeapTupleHeaderSetTypeId(HeapTupleHeaderData *tup, Oid datum_typeid)
516 : {
517 23598176 : tup->t_choice.t_datum.datum_typeid = datum_typeid;
518 23598176 : }
519 :
520 : static inline int32
521 1657036 : HeapTupleHeaderGetTypMod(const HeapTupleHeaderData *tup)
522 : {
523 1657036 : return tup->t_choice.t_datum.datum_typmod;
524 : }
525 :
526 : static inline void
527 23598176 : HeapTupleHeaderSetTypMod(HeapTupleHeaderData *tup, int32 typmod)
528 : {
529 23598176 : tup->t_choice.t_datum.datum_typmod = typmod;
530 23598176 : }
531 :
532 : /*
533 : * Note that we stop considering a tuple HOT-updated as soon as it is known
534 : * aborted or the would-be updating transaction is known aborted. For best
535 : * efficiency, check tuple visibility before using this function, so that the
536 : * INVALID bits will be as up to date as possible.
537 : */
538 : static inline bool
539 36466906 : HeapTupleHeaderIsHotUpdated(const HeapTupleHeaderData *tup)
540 : {
541 : return
542 38490902 : (tup->t_infomask2 & HEAP_HOT_UPDATED) != 0 &&
543 38490902 : (tup->t_infomask & HEAP_XMAX_INVALID) == 0 &&
544 2023996 : !HeapTupleHeaderXminInvalid(tup);
545 : }
546 :
547 : static inline void
548 342010 : HeapTupleHeaderSetHotUpdated(HeapTupleHeaderData *tup)
549 : {
550 342010 : tup->t_infomask2 |= HEAP_HOT_UPDATED;
551 342010 : }
552 :
553 : static inline void
554 4497578 : HeapTupleHeaderClearHotUpdated(HeapTupleHeaderData *tup)
555 : {
556 4497578 : tup->t_infomask2 &= ~HEAP_HOT_UPDATED;
557 4497578 : }
558 :
559 : static inline bool
560 117505144 : HeapTupleHeaderIsHeapOnly(const HeapTupleHeaderData *tup) \
561 : {
562 117505144 : return (tup->t_infomask2 & HEAP_ONLY_TUPLE) != 0;
563 : }
564 :
565 : static inline void
566 541564 : HeapTupleHeaderSetHeapOnly(HeapTupleHeaderData *tup)
567 : {
568 541564 : tup->t_infomask2 |= HEAP_ONLY_TUPLE;
569 541564 : }
570 :
571 : static inline void
572 616804 : HeapTupleHeaderClearHeapOnly(HeapTupleHeaderData *tup)
573 : {
574 616804 : tup->t_infomask2 &= ~HEAP_ONLY_TUPLE;
575 616804 : }
576 :
577 : /*
578 : * These are used with both HeapTuple and MinimalTuple, so they must be
579 : * macros.
580 : */
581 :
582 : #define HeapTupleHeaderGetNatts(tup) \
583 : ((tup)->t_infomask2 & HEAP_NATTS_MASK)
584 :
585 : #define HeapTupleHeaderSetNatts(tup, natts) \
586 : ( \
587 : (tup)->t_infomask2 = ((tup)->t_infomask2 & ~HEAP_NATTS_MASK) | (natts) \
588 : )
589 :
590 : #define HeapTupleHeaderHasExternal(tup) \
591 : (((tup)->t_infomask & HEAP_HASEXTERNAL) != 0)
592 :
593 :
594 : /*
595 : * BITMAPLEN(NATTS) -
596 : * Computes size of null bitmap given number of data columns.
597 : */
598 : static inline int
599 7206432 : BITMAPLEN(int NATTS)
600 : {
601 7206432 : return (NATTS + 7) / 8;
602 : }
603 :
604 : /*
605 : * MaxHeapTupleSize is the maximum allowed size of a heap tuple, including
606 : * header and MAXALIGN alignment padding. Basically it's BLCKSZ minus the
607 : * other stuff that has to be on a disk page. Since heap pages use no
608 : * "special space", there's no deduction for that.
609 : *
610 : * NOTE: we allow for the ItemId that must point to the tuple, ensuring that
611 : * an otherwise-empty page can indeed hold a tuple of this size. Because
612 : * ItemIds and tuples have different alignment requirements, don't assume that
613 : * you can, say, fit 2 tuples of size MaxHeapTupleSize/2 on the same page.
614 : */
615 : #define MaxHeapTupleSize (BLCKSZ - MAXALIGN(SizeOfPageHeaderData + sizeof(ItemIdData)))
616 : #define MinHeapTupleSize MAXALIGN(SizeofHeapTupleHeader)
617 :
618 : /*
619 : * MaxHeapTuplesPerPage is an upper bound on the number of tuples that can
620 : * fit on one heap page. (Note that indexes could have more, because they
621 : * use a smaller tuple header.) We arrive at the divisor because each tuple
622 : * must be maxaligned, and it must have an associated line pointer.
623 : *
624 : * Note: with HOT, there could theoretically be more line pointers (not actual
625 : * tuples) than this on a heap page. However we constrain the number of line
626 : * pointers to this anyway, to avoid excessive line-pointer bloat and not
627 : * require increases in the size of work arrays.
628 : */
629 : #define MaxHeapTuplesPerPage \
630 : ((int) ((BLCKSZ - SizeOfPageHeaderData) / \
631 : (MAXALIGN(SizeofHeapTupleHeader) + sizeof(ItemIdData))))
632 :
633 : /*
634 : * MaxAttrSize is a somewhat arbitrary upper limit on the declared size of
635 : * data fields of char(n) and similar types. It need not have anything
636 : * directly to do with the *actual* upper limit of varlena values, which
637 : * is currently 1Gb (see TOAST structures in postgres.h). I've set it
638 : * at 10Mb which seems like a reasonable number --- tgl 8/6/00.
639 : */
640 : #define MaxAttrSize (10 * 1024 * 1024)
641 :
642 :
643 : /*
644 : * MinimalTuple is an alternative representation that is used for transient
645 : * tuples inside the executor, in places where transaction status information
646 : * is not required, the tuple rowtype is known, and shaving off a few bytes
647 : * is worthwhile because we need to store many tuples. The representation
648 : * is chosen so that tuple access routines can work with either full or
649 : * minimal tuples via a HeapTupleData pointer structure. The access routines
650 : * see no difference, except that they must not access the transaction status
651 : * or t_ctid fields because those aren't there.
652 : *
653 : * For the most part, MinimalTuples should be accessed via TupleTableSlot
654 : * routines. These routines will prevent access to the "system columns"
655 : * and thereby prevent accidental use of the nonexistent fields.
656 : *
657 : * MinimalTupleData contains a length word, some padding, and fields matching
658 : * HeapTupleHeaderData beginning with t_infomask2. The padding is chosen so
659 : * that offsetof(t_infomask2) is the same modulo MAXIMUM_ALIGNOF in both
660 : * structs. This makes data alignment rules equivalent in both cases.
661 : *
662 : * When a minimal tuple is accessed via a HeapTupleData pointer, t_data is
663 : * set to point MINIMAL_TUPLE_OFFSET bytes before the actual start of the
664 : * minimal tuple --- that is, where a full tuple matching the minimal tuple's
665 : * data would start. This trick is what makes the structs seem equivalent.
666 : *
667 : * Note that t_hoff is computed the same as in a full tuple, hence it includes
668 : * the MINIMAL_TUPLE_OFFSET distance. t_len does not include that, however.
669 : *
670 : * MINIMAL_TUPLE_DATA_OFFSET is the offset to the first useful (non-pad) data
671 : * other than the length word. tuplesort.c and tuplestore.c use this to avoid
672 : * writing the padding to disk.
673 : */
674 : #define MINIMAL_TUPLE_OFFSET \
675 : ((offsetof(HeapTupleHeaderData, t_infomask2) - sizeof(uint32)) / MAXIMUM_ALIGNOF * MAXIMUM_ALIGNOF)
676 : #define MINIMAL_TUPLE_PADDING \
677 : ((offsetof(HeapTupleHeaderData, t_infomask2) - sizeof(uint32)) % MAXIMUM_ALIGNOF)
678 : #define MINIMAL_TUPLE_DATA_OFFSET \
679 : offsetof(MinimalTupleData, t_infomask2)
680 :
681 : struct MinimalTupleData
682 : {
683 : uint32 t_len; /* actual length of minimal tuple */
684 :
685 : char mt_padding[MINIMAL_TUPLE_PADDING];
686 :
687 : /* Fields below here must match HeapTupleHeaderData! */
688 :
689 : uint16 t_infomask2; /* number of attributes + various flags */
690 :
691 : uint16 t_infomask; /* various flag bits, see below */
692 :
693 : uint8 t_hoff; /* sizeof header incl. bitmap, padding */
694 :
695 : /* ^ - 23 bytes - ^ */
696 :
697 : bits8 t_bits[FLEXIBLE_ARRAY_MEMBER]; /* bitmap of NULLs */
698 :
699 : /* MORE DATA FOLLOWS AT END OF STRUCT */
700 : };
701 :
702 : /* typedef appears in htup.h */
703 :
704 : #define SizeofMinimalTupleHeader offsetof(MinimalTupleData, t_bits)
705 :
706 : /*
707 : * MinimalTuple accessor functions
708 : */
709 :
710 : static inline bool
711 11113702 : HeapTupleHeaderHasMatch(const MinimalTupleData *tup)
712 : {
713 11113702 : return (tup->t_infomask2 & HEAP_TUPLE_HAS_MATCH) != 0;
714 : }
715 :
716 : static inline void
717 5822672 : HeapTupleHeaderSetMatch(MinimalTupleData *tup)
718 : {
719 5822672 : tup->t_infomask2 |= HEAP_TUPLE_HAS_MATCH;
720 5822672 : }
721 :
722 : static inline void
723 10129456 : HeapTupleHeaderClearMatch(MinimalTupleData *tup)
724 : {
725 10129456 : tup->t_infomask2 &= ~HEAP_TUPLE_HAS_MATCH;
726 10129456 : }
727 :
728 :
729 : /*
730 : * GETSTRUCT - given a HeapTuple pointer, return address of the user data
731 : */
732 : static inline void *
733 153817192 : GETSTRUCT(const HeapTupleData *tuple)
734 : {
735 153817192 : return ((char *) (tuple->t_data) + tuple->t_data->t_hoff);
736 : }
737 :
738 : /*
739 : * Accessor functions to be used with HeapTuple pointers.
740 : */
741 :
742 : static inline bool
743 932002140 : HeapTupleHasNulls(const HeapTupleData *tuple)
744 : {
745 932002140 : return (tuple->t_data->t_infomask & HEAP_HASNULL) != 0;
746 : }
747 :
748 : static inline bool
749 455575596 : HeapTupleNoNulls(const HeapTupleData *tuple)
750 : {
751 455575596 : return !HeapTupleHasNulls(tuple);
752 : }
753 :
754 : static inline bool
755 48301222 : HeapTupleHasVarWidth(const HeapTupleData *tuple)
756 : {
757 48301222 : return (tuple->t_data->t_infomask & HEAP_HASVARWIDTH) != 0;
758 : }
759 :
760 : static inline bool
761 : HeapTupleAllFixed(const HeapTupleData *tuple)
762 : {
763 : return !HeapTupleHasVarWidth(tuple);
764 : }
765 :
766 : static inline bool
767 28136780 : HeapTupleHasExternal(const HeapTupleData *tuple)
768 : {
769 28136780 : return (tuple->t_data->t_infomask & HEAP_HASEXTERNAL) != 0;
770 : }
771 :
772 : static inline bool
773 14396986 : HeapTupleIsHotUpdated(const HeapTupleData *tuple)
774 : {
775 14396986 : return HeapTupleHeaderIsHotUpdated(tuple->t_data);
776 : }
777 :
778 : static inline void
779 270782 : HeapTupleSetHotUpdated(const HeapTupleData *tuple)
780 : {
781 270782 : HeapTupleHeaderSetHotUpdated(tuple->t_data);
782 270782 : }
783 :
784 : static inline void
785 593682 : HeapTupleClearHotUpdated(const HeapTupleData *tuple)
786 : {
787 593682 : HeapTupleHeaderClearHotUpdated(tuple->t_data);
788 593682 : }
789 :
790 : static inline bool
791 59678784 : HeapTupleIsHeapOnly(const HeapTupleData *tuple)
792 : {
793 59678784 : return HeapTupleHeaderIsHeapOnly(tuple->t_data);
794 : }
795 :
796 : static inline void
797 541564 : HeapTupleSetHeapOnly(const HeapTupleData *tuple)
798 : {
799 541564 : HeapTupleHeaderSetHeapOnly(tuple->t_data);
800 541564 : }
801 :
802 : static inline void
803 616804 : HeapTupleClearHeapOnly(const HeapTupleData *tuple)
804 : {
805 616804 : HeapTupleHeaderClearHeapOnly(tuple->t_data);
806 616804 : }
807 :
808 : /* prototypes for functions in common/heaptuple.c */
809 : extern Size heap_compute_data_size(TupleDesc tupleDesc,
810 : const Datum *values, const bool *isnull);
811 : extern void heap_fill_tuple(TupleDesc tupleDesc,
812 : const Datum *values, const bool *isnull,
813 : char *data, Size data_size,
814 : uint16 *infomask, bits8 *bit);
815 : extern bool heap_attisnull(HeapTuple tup, int attnum, TupleDesc tupleDesc);
816 : extern Datum nocachegetattr(HeapTuple tup, int attnum,
817 : TupleDesc tupleDesc);
818 : extern Datum heap_getsysattr(HeapTuple tup, int attnum, TupleDesc tupleDesc,
819 : bool *isnull);
820 : extern Datum getmissingattr(TupleDesc tupleDesc,
821 : int attnum, bool *isnull);
822 : extern HeapTuple heap_copytuple(HeapTuple tuple);
823 : extern void heap_copytuple_with_tuple(HeapTuple src, HeapTuple dest);
824 : extern Datum heap_copy_tuple_as_datum(HeapTuple tuple, TupleDesc tupleDesc);
825 : extern HeapTuple heap_form_tuple(TupleDesc tupleDescriptor,
826 : const Datum *values, const bool *isnull);
827 : extern HeapTuple heap_modify_tuple(HeapTuple tuple,
828 : TupleDesc tupleDesc,
829 : const Datum *replValues,
830 : const bool *replIsnull,
831 : const bool *doReplace);
832 : extern HeapTuple heap_modify_tuple_by_cols(HeapTuple tuple,
833 : TupleDesc tupleDesc,
834 : int nCols,
835 : const int *replCols,
836 : const Datum *replValues,
837 : const bool *replIsnull);
838 : extern void heap_deform_tuple(HeapTuple tuple, TupleDesc tupleDesc,
839 : Datum *values, bool *isnull);
840 : extern void heap_freetuple(HeapTuple htup);
841 : extern MinimalTuple heap_form_minimal_tuple(TupleDesc tupleDescriptor,
842 : const Datum *values, const bool *isnull);
843 : extern void heap_free_minimal_tuple(MinimalTuple mtup);
844 : extern MinimalTuple heap_copy_minimal_tuple(MinimalTuple mtup);
845 : extern HeapTuple heap_tuple_from_minimal_tuple(MinimalTuple mtup);
846 : extern MinimalTuple minimal_tuple_from_heap_tuple(HeapTuple htup);
847 : extern size_t varsize_any(void *p);
848 : extern HeapTuple heap_expand_tuple(HeapTuple sourceTuple, TupleDesc tupleDesc);
849 : extern MinimalTuple minimal_expand_tuple(HeapTuple sourceTuple, TupleDesc tupleDesc);
850 :
851 : #ifndef FRONTEND
852 : /*
853 : * fastgetattr
854 : * Fetch a user attribute's value as a Datum (might be either a
855 : * value, or a pointer into the data area of the tuple).
856 : *
857 : * This must not be used when a system attribute might be requested.
858 : * Furthermore, the passed attnum MUST be valid. Use heap_getattr()
859 : * instead, if in doubt.
860 : *
861 : * This gets called many times, so we macro the cacheable and NULL
862 : * lookups, and call nocachegetattr() for the rest.
863 : */
864 : static inline Datum
865 266049954 : fastgetattr(HeapTuple tup, int attnum, TupleDesc tupleDesc, bool *isnull)
866 : {
867 : Assert(attnum > 0);
868 :
869 266049954 : *isnull = false;
870 266049954 : if (HeapTupleNoNulls(tup))
871 : {
872 : CompactAttribute *att;
873 :
874 112087132 : att = TupleDescCompactAttr(tupleDesc, attnum - 1);
875 112087132 : if (att->attcacheoff >= 0)
876 67619514 : return fetchatt(att, (char *) tup->t_data + tup->t_data->t_hoff +
877 : att->attcacheoff);
878 : else
879 44467618 : return nocachegetattr(tup, attnum, tupleDesc);
880 : }
881 : else
882 : {
883 153962822 : if (att_isnull(attnum - 1, tup->t_data->t_bits))
884 : {
885 18032368 : *isnull = true;
886 18032368 : return (Datum) NULL;
887 : }
888 : else
889 135930454 : return nocachegetattr(tup, attnum, tupleDesc);
890 : }
891 : }
892 :
893 : /*
894 : * heap_getattr
895 : * Extract an attribute of a heap tuple and return it as a Datum.
896 : * This works for either system or user attributes. The given attnum
897 : * is properly range-checked.
898 : *
899 : * If the field in question has a NULL value, we return a zero Datum
900 : * and set *isnull == true. Otherwise, we set *isnull == false.
901 : *
902 : * <tup> is the pointer to the heap tuple. <attnum> is the attribute
903 : * number of the column (field) caller wants. <tupleDesc> is a
904 : * pointer to the structure describing the row and all its fields.
905 : *
906 : */
907 : static inline Datum
908 248618022 : heap_getattr(HeapTuple tup, int attnum, TupleDesc tupleDesc, bool *isnull)
909 : {
910 248618022 : if (attnum > 0)
911 : {
912 248618022 : if (attnum > (int) HeapTupleHeaderGetNatts(tup->t_data))
913 332 : return getmissingattr(tupleDesc, attnum, isnull);
914 : else
915 248617690 : return fastgetattr(tup, attnum, tupleDesc, isnull);
916 : }
917 : else
918 0 : return heap_getsysattr(tup, attnum, tupleDesc, isnull);
919 : }
920 : #endif /* FRONTEND */
921 :
922 : #endif /* HTUP_DETAILS_H */
|
