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1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * htup_details.h
4 : : * POSTGRES heap tuple header definitions.
5 : : *
6 : : *
7 : : * Portions Copyright (c) 1996-2026, 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 : 5864784 : HEAP_XMAX_IS_LOCKED_ONLY(uint16 infomask)
231 : : {
232 [ + + ]: 5864784 : return (infomask & HEAP_XMAX_LOCK_ONLY) ||
233 : 5352443 : (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 : 326 : HEAP_LOCKED_UPGRADED(uint16 infomask)
256 : : {
257 : 326 : return
258 [ + + ]: 326 : (infomask & HEAP_XMAX_IS_MULTI) != 0 &&
259 [ + - ]: 2 : (infomask & HEAP_XMAX_LOCK_ONLY) != 0 &&
260 : 0 : (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 : 416 : HEAP_XMAX_IS_SHR_LOCKED(uint16 infomask)
268 : : {
269 : 416 : return (infomask & HEAP_LOCK_MASK) == HEAP_XMAX_SHR_LOCK;
270 : : }
271 : :
272 : : static inline bool
273 : 435 : HEAP_XMAX_IS_EXCL_LOCKED(uint16 infomask)
274 : : {
275 : 435 : return (infomask & HEAP_LOCK_MASK) == HEAP_XMAX_EXCL_LOCK;
276 : : }
277 : :
278 : : static inline bool
279 : 400269 : HEAP_XMAX_IS_KEYSHR_LOCKED(uint16 infomask)
280 : : {
281 : 400269 : 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 : 32576065 : HeapTupleHeaderGetRawXmin(const HeapTupleHeaderData *tup)
324 : : {
325 : 32576065 : return tup->t_choice.t_heap.t_xmin;
326 : : }
327 : :
328 : : static inline TransactionId
329 : 10268379 : HeapTupleHeaderGetXmin(const HeapTupleHeaderData *tup)
330 : : {
331 [ + + ]: 10268379 : return HeapTupleHeaderXminFrozen(tup) ?
332 : 9943594 : FrozenTransactionId : HeapTupleHeaderGetRawXmin(tup);
333 : : }
334 : :
335 : : static inline void
336 : 1930439 : HeapTupleHeaderSetXmin(HeapTupleHeaderData *tup, TransactionId xid)
337 : : {
338 : 1930439 : tup->t_choice.t_heap.t_xmin = xid;
339 : 1930439 : }
340 : :
341 : : static inline bool
342 : 26519878 : HeapTupleHeaderXminCommitted(const HeapTupleHeaderData *tup)
343 : : {
344 : 26519878 : return (tup->t_infomask & HEAP_XMIN_COMMITTED) != 0;
345 : : }
346 : :
347 : : static inline bool
348 : 9658108 : HeapTupleHeaderXminInvalid(const HeapTupleHeaderData *tup) \
349 : : {
350 : 9658108 : return (tup->t_infomask & (HEAP_XMIN_COMMITTED | HEAP_XMIN_INVALID)) ==
351 : : HEAP_XMIN_INVALID;
352 : : }
353 : :
354 : : static inline bool
355 : 20921915 : HeapTupleHeaderXminFrozen(const HeapTupleHeaderData *tup)
356 : : {
357 : 20921915 : 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 : 853 : HeapTupleHeaderSetXminFrozen(HeapTupleHeaderData *tup)
376 : : {
377 [ + - ]: 853 : Assert(!HeapTupleHeaderXminInvalid(tup));
378 : 853 : tup->t_infomask |= HEAP_XMIN_FROZEN;
379 : 853 : }
380 : :
381 : : static inline TransactionId
382 : 10998423 : HeapTupleHeaderGetRawXmax(const HeapTupleHeaderData *tup)
383 : : {
384 : 10998423 : return tup->t_choice.t_heap.t_xmax;
385 : : }
386 : :
387 : : static inline void
388 : 2442259 : HeapTupleHeaderSetXmax(HeapTupleHeaderData *tup, TransactionId xid)
389 : : {
390 : 2442259 : tup->t_choice.t_heap.t_xmax = xid;
391 : 2442259 : }
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 : 1477726 : HeapTupleHeaderGetUpdateXid(const HeapTupleHeaderData *tup)
403 : : {
404 [ + + ]: 1477726 : if (!((tup)->t_infomask & HEAP_XMAX_INVALID) &&
405 [ - + # # ]: 1453597 : ((tup)->t_infomask & HEAP_XMAX_IS_MULTI) &&
406 : 0 : !((tup)->t_infomask & HEAP_XMAX_LOCK_ONLY))
407 : 0 : return HeapTupleGetUpdateXid(tup);
408 : : else
409 : 1477726 : return HeapTupleHeaderGetRawXmax(tup);
410 : 1477726 : }
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 : 4378742 : HeapTupleHeaderGetRawCommandId(const HeapTupleHeaderData *tup)
421 : : {
422 : 4378742 : 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 : 1925291 : HeapTupleHeaderSetCmin(HeapTupleHeaderData *tup, CommandId cid)
428 : : {
429 [ + - ]: 1925291 : Assert(!(tup->t_infomask & HEAP_MOVED));
430 : 1925291 : tup->t_choice.t_heap.t_field3.t_cid = cid;
431 : 1925291 : tup->t_infomask &= ~HEAP_COMBOCID;
432 : 1925291 : }
433 : :
434 : : /* SetCmax must be used after HeapTupleHeaderAdjustCmax; see combocid.c */
435 : : static inline void
436 : 334580 : HeapTupleHeaderSetCmax(HeapTupleHeaderData *tup, CommandId cid, bool iscombo)
437 : : {
438 [ + - ]: 334580 : Assert(!((tup)->t_infomask & HEAP_MOVED));
439 : 334580 : tup->t_choice.t_heap.t_field3.t_cid = cid;
440 [ + + ]: 334580 : if (iscombo)
441 : 15677 : tup->t_infomask |= HEAP_COMBOCID;
442 : : else
443 : 318903 : tup->t_infomask &= ~HEAP_COMBOCID;
444 : 334580 : }
445 : :
446 : : static inline TransactionId
447 : 1258144 : HeapTupleHeaderGetXvac(const HeapTupleHeaderData *tup)
448 : : {
449 [ - + ]: 1258144 : if (tup->t_infomask & HEAP_MOVED)
450 : 0 : return tup->t_choice.t_heap.t_field3.t_xvac;
451 : : else
452 : 1258144 : return InvalidTransactionId;
453 : 1258144 : }
454 : :
455 : : static inline void
456 : 0 : HeapTupleHeaderSetXvac(HeapTupleHeaderData *tup, TransactionId xid)
457 : : {
458 [ # # ]: 0 : 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 : 173 : HeapTupleHeaderIsSpeculative(const HeapTupleHeaderData *tup)
467 : : {
468 : 173 : return ItemPointerGetOffsetNumberNoCheck(&tup->t_ctid) == SpecTokenOffsetNumber;
469 : : }
470 : :
471 : : static inline BlockNumber
472 : 0 : HeapTupleHeaderGetSpeculativeToken(const HeapTupleHeaderData *tup)
473 : : {
474 [ # # ]: 0 : Assert(HeapTupleHeaderIsSpeculative(tup));
475 : 0 : return ItemPointerGetBlockNumber(&tup->t_ctid);
476 : : }
477 : :
478 : : static inline void
479 : 87 : HeapTupleHeaderSetSpeculativeToken(HeapTupleHeaderData *tup, BlockNumber token)
480 : : {
481 : 87 : ItemPointerSet(&tup->t_ctid, token, SpecTokenOffsetNumber);
482 : 87 : }
483 : :
484 : : static inline bool
485 : 30963 : HeapTupleHeaderIndicatesMovedPartitions(const HeapTupleHeaderData *tup)
486 : : {
487 : 30963 : return ItemPointerIndicatesMovedPartitions(&tup->t_ctid);
488 : : }
489 : :
490 : : static inline void
491 : 145 : HeapTupleHeaderSetMovedPartitions(HeapTupleHeaderData *tup)
492 : : {
493 : 145 : ItemPointerSetMovedPartitions(&tup->t_ctid);
494 : 145 : }
495 : :
496 : : static inline uint32
497 : 83106 : HeapTupleHeaderGetDatumLength(const HeapTupleHeaderData *tup)
498 : : {
499 : 83106 : return VARSIZE(tup);
500 : : }
501 : :
502 : : static inline void
503 : 2759847 : HeapTupleHeaderSetDatumLength(HeapTupleHeaderData *tup, uint32 len)
504 : : {
505 : 2759847 : SET_VARSIZE(tup, len);
506 : 2759847 : }
507 : :
508 : : static inline Oid
509 : 82791 : HeapTupleHeaderGetTypeId(const HeapTupleHeaderData *tup)
510 : : {
511 : 82791 : return tup->t_choice.t_datum.datum_typeid;
512 : : }
513 : :
514 : : static inline void
515 : 2762558 : HeapTupleHeaderSetTypeId(HeapTupleHeaderData *tup, Oid datum_typeid)
516 : : {
517 : 2762558 : tup->t_choice.t_datum.datum_typeid = datum_typeid;
518 : 2762558 : }
519 : :
520 : : static inline int32
521 : 81831 : HeapTupleHeaderGetTypMod(const HeapTupleHeaderData *tup)
522 : : {
523 : 81831 : return tup->t_choice.t_datum.datum_typmod;
524 : : }
525 : :
526 : : static inline void
527 : 2762558 : HeapTupleHeaderSetTypMod(HeapTupleHeaderData *tup, int32 typmod)
528 : : {
529 : 2762558 : tup->t_choice.t_datum.datum_typmod = typmod;
530 : 2762558 : }
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 : 4160649 : HeapTupleHeaderIsHotUpdated(const HeapTupleHeaderData *tup)
540 : : {
541 : 4160649 : return
542 [ + + ]: 4160649 : (tup->t_infomask2 & HEAP_HOT_UPDATED) != 0 &&
543 [ + + ]: 141019 : (tup->t_infomask & HEAP_XMAX_INVALID) == 0 &&
544 : 141017 : !HeapTupleHeaderXminInvalid(tup);
545 : : }
546 : :
547 : : static inline void
548 : 14631 : HeapTupleHeaderSetHotUpdated(HeapTupleHeaderData *tup)
549 : : {
550 : 14631 : tup->t_infomask2 |= HEAP_HOT_UPDATED;
551 : 14631 : }
552 : :
553 : : static inline void
554 : 321038 : HeapTupleHeaderClearHotUpdated(HeapTupleHeaderData *tup)
555 : : {
556 : 321038 : tup->t_infomask2 &= ~HEAP_HOT_UPDATED;
557 : 321038 : }
558 : :
559 : : static inline bool
560 : 9443308 : HeapTupleHeaderIsHeapOnly(const HeapTupleHeaderData *tup) \
561 : : {
562 : 9443308 : return (tup->t_infomask2 & HEAP_ONLY_TUPLE) != 0;
563 : : }
564 : :
565 : : static inline void
566 : 29262 : HeapTupleHeaderSetHeapOnly(HeapTupleHeaderData *tup)
567 : : {
568 : 29262 : tup->t_infomask2 |= HEAP_ONLY_TUPLE;
569 : 29262 : }
570 : :
571 : : static inline void
572 : 18958 : HeapTupleHeaderClearHeapOnly(HeapTupleHeaderData *tup)
573 : : {
574 : 18958 : tup->t_infomask2 &= ~HEAP_ONLY_TUPLE;
575 : 18958 : }
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 : 252959 : BITMAPLEN(int NATTS)
600 : : {
601 : 252959 : 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 varatt.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 : 1288649 : HeapTupleHeaderHasMatch(const MinimalTupleData *tup)
712 : : {
713 : 1288649 : return (tup->t_infomask2 & HEAP_TUPLE_HAS_MATCH) != 0;
714 : : }
715 : :
716 : : static inline void
717 : 927767 : HeapTupleHeaderSetMatch(MinimalTupleData *tup)
718 : : {
719 : 927767 : tup->t_infomask2 |= HEAP_TUPLE_HAS_MATCH;
720 : 927767 : }
721 : :
722 : : static inline void
723 : 1772476 : HeapTupleHeaderClearMatch(MinimalTupleData *tup)
724 : : {
725 : 1772476 : tup->t_infomask2 &= ~HEAP_TUPLE_HAS_MATCH;
726 : 1772476 : }
727 : :
728 : :
729 : : /*
730 : : * GETSTRUCT - given a HeapTuple pointer, return address of the user data
731 : : */
732 : : static inline void *
733 : 13133511 : GETSTRUCT(const HeapTupleData *tuple)
734 : : {
735 : 13133511 : 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 : 55660668 : HeapTupleHasNulls(const HeapTupleData *tuple)
744 : : {
745 : 55660668 : return (tuple->t_data->t_infomask & HEAP_HASNULL) != 0;
746 : : }
747 : :
748 : : static inline bool
749 : 15687342 : HeapTupleNoNulls(const HeapTupleData *tuple)
750 : : {
751 : 15687342 : return !HeapTupleHasNulls(tuple);
752 : : }
753 : :
754 : : static inline bool
755 : 760870 : HeapTupleHasVarWidth(const HeapTupleData *tuple)
756 : : {
757 : 760870 : 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 : 2385587 : HeapTupleHasExternal(const HeapTupleData *tuple)
768 : : {
769 : 2385587 : return (tuple->t_data->t_infomask & HEAP_HASEXTERNAL) != 0;
770 : : }
771 : :
772 : : static inline bool
773 : 2143109 : HeapTupleIsHotUpdated(const HeapTupleData *tuple)
774 : : {
775 : 2143109 : return HeapTupleHeaderIsHotUpdated(tuple->t_data);
776 : : }
777 : :
778 : : static inline void
779 : 14631 : HeapTupleSetHotUpdated(const HeapTupleData *tuple)
780 : : {
781 : 14631 : HeapTupleHeaderSetHotUpdated(tuple->t_data);
782 : 14631 : }
783 : :
784 : : static inline void
785 : 16129 : HeapTupleClearHotUpdated(const HeapTupleData *tuple)
786 : : {
787 : 16129 : HeapTupleHeaderClearHotUpdated(tuple->t_data);
788 : 16129 : }
789 : :
790 : : static inline bool
791 : 6314746 : HeapTupleIsHeapOnly(const HeapTupleData *tuple)
792 : : {
793 : 6314746 : return HeapTupleHeaderIsHeapOnly(tuple->t_data);
794 : : }
795 : :
796 : : static inline void
797 : 29262 : HeapTupleSetHeapOnly(const HeapTupleData *tuple)
798 : : {
799 : 29262 : HeapTupleHeaderSetHeapOnly(tuple->t_data);
800 : 29262 : }
801 : :
802 : : static inline void
803 : 18958 : HeapTupleClearHeapOnly(const HeapTupleData *tuple)
804 : : {
805 : 18958 : HeapTupleHeaderClearHeapOnly(tuple->t_data);
806 : 18958 : }
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 : : Size extra);
844 : : extern void heap_free_minimal_tuple(MinimalTuple mtup);
845 : : extern MinimalTuple heap_copy_minimal_tuple(MinimalTuple mtup, Size extra);
846 : : extern HeapTuple heap_tuple_from_minimal_tuple(MinimalTuple mtup);
847 : : extern MinimalTuple minimal_tuple_from_heap_tuple(HeapTuple htup, Size extra);
848 : : extern size_t varsize_any(void *p);
849 : : extern HeapTuple heap_expand_tuple(HeapTuple sourceTuple, TupleDesc tupleDesc);
850 : : extern MinimalTuple minimal_expand_tuple(HeapTuple sourceTuple, TupleDesc tupleDesc);
851 : :
852 : : #ifndef FRONTEND
853 : : /*
854 : : * fastgetattr
855 : : * Fetch a user attribute's value as a Datum (might be either a
856 : : * value, or a pointer into the data area of the tuple).
857 : : *
858 : : * This must not be used when a system attribute might be requested.
859 : : * Furthermore, the passed attnum MUST be valid. Use heap_getattr()
860 : : * instead, if in doubt.
861 : : *
862 : : * This gets called many times, so we macro the cacheable and NULL
863 : : * lookups, and call nocachegetattr() for the rest.
864 : : */
865 : : static inline Datum
866 : 9833870 : fastgetattr(HeapTuple tup, int attnum, TupleDesc tupleDesc, bool *isnull)
867 : : {
868 [ + - ]: 9833870 : Assert(attnum > 0);
869 : :
870 : 9833870 : *isnull = false;
871 [ + + ]: 9833870 : if (HeapTupleNoNulls(tup))
872 : : {
873 : 5781063 : CompactAttribute *att;
874 : :
875 : 5781063 : att = TupleDescCompactAttr(tupleDesc, attnum - 1);
876 [ + + ]: 5781063 : if (att->attcacheoff >= 0)
877 : 5177591 : return fetchatt(att, (char *) tup->t_data + tup->t_data->t_hoff +
878 : : att->attcacheoff);
879 : : else
880 : 603472 : return nocachegetattr(tup, attnum, tupleDesc);
881 : 5781063 : }
882 : : else
883 : : {
884 [ + + ]: 4052807 : if (att_isnull(attnum - 1, tup->t_data->t_bits))
885 : : {
886 : 704479 : *isnull = true;
887 : 704479 : return (Datum) 0;
888 : : }
889 : : else
890 : 3348328 : return nocachegetattr(tup, attnum, tupleDesc);
891 : : }
892 : 9833870 : }
893 : :
894 : : /*
895 : : * heap_getattr
896 : : * Extract an attribute of a heap tuple and return it as a Datum.
897 : : * This works for either system or user attributes. The given attnum
898 : : * is properly range-checked.
899 : : *
900 : : * If the field in question has a NULL value, we return a zero Datum
901 : : * and set *isnull == true. Otherwise, we set *isnull == false.
902 : : *
903 : : * <tup> is the pointer to the heap tuple. <attnum> is the attribute
904 : : * number of the column (field) caller wants. <tupleDesc> is a
905 : : * pointer to the structure describing the row and all its fields.
906 : : *
907 : : */
908 : : static inline Datum
909 : 9720609 : heap_getattr(HeapTuple tup, int attnum, TupleDesc tupleDesc, bool *isnull)
910 : : {
911 [ + - ]: 9720609 : if (attnum > 0)
912 : : {
913 [ + + ]: 9720609 : if (attnum > (int) HeapTupleHeaderGetNatts(tup->t_data))
914 : 39 : return getmissingattr(tupleDesc, attnum, isnull);
915 : : else
916 : 9720570 : return fastgetattr(tup, attnum, tupleDesc, isnull);
917 : : }
918 : : else
919 : 0 : return heap_getsysattr(tup, attnum, tupleDesc, isnull);
920 : 9720609 : }
921 : : #endif /* FRONTEND */
922 : :
923 : : #endif /* HTUP_DETAILS_H */
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