1 /*-------------------------------------------------------------------------
4 * POSTGRES heap tuple header definitions.
7 * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
10 * src/include/access/htup_details.h
12 *-------------------------------------------------------------------------
14 #ifndef HTUP_DETAILS_H
15 #define HTUP_DETAILS_H
17 #include "access/htup.h"
18 #include "access/tupdesc.h"
19 #include "access/tupmacs.h"
20 #include "storage/bufpage.h"
23 * MaxTupleAttributeNumber limits the number of (user) columns in a tuple.
24 * The key limit on this value is that the size of the fixed overhead for
25 * a tuple, plus the size of the null-values bitmap (at 1 bit per column),
26 * plus MAXALIGN alignment, must fit into t_hoff which is uint8. On most
27 * machines the upper limit without making t_hoff wider would be a little
28 * over 1700. We use round numbers here and for MaxHeapAttributeNumber
29 * so that alterations in HeapTupleHeaderData layout won't change the
30 * supported max number of columns.
32 #define MaxTupleAttributeNumber 1664 /* 8 * 208 */
35 * MaxHeapAttributeNumber limits the number of (user) columns in a table.
36 * This should be somewhat less than MaxTupleAttributeNumber. It must be
37 * at least one less, else we will fail to do UPDATEs on a maximal-width
38 * table (because UPDATE has to form working tuples that include CTID).
39 * In practice we want some additional daylight so that we can gracefully
40 * support operations that add hidden "resjunk" columns, for example
41 * SELECT * FROM wide_table ORDER BY foo, bar, baz.
42 * In any case, depending on column data types you will likely be running
43 * into the disk-block-based limit on overall tuple size if you have more
44 * than a thousand or so columns. TOAST won't help.
46 #define MaxHeapAttributeNumber 1600 /* 8 * 200 */
49 * Heap tuple header. To avoid wasting space, the fields should be
50 * laid out in such a way as to avoid structure padding.
52 * Datums of composite types (row types) share the same general structure
53 * as on-disk tuples, so that the same routines can be used to build and
54 * examine them. However the requirements are slightly different: a Datum
55 * does not need any transaction visibility information, and it does need
56 * a length word and some embedded type information. We can achieve this
57 * by overlaying the xmin/cmin/xmax/cmax/xvac fields of a heap tuple
58 * with the fields needed in the Datum case. Typically, all tuples built
59 * in-memory will be initialized with the Datum fields; but when a tuple is
60 * about to be inserted in a table, the transaction fields will be filled,
61 * overwriting the datum fields.
63 * The overall structure of a heap tuple looks like:
64 * fixed fields (HeapTupleHeaderData struct)
65 * nulls bitmap (if HEAP_HASNULL is set in t_infomask)
66 * alignment padding (as needed to make user data MAXALIGN'd)
67 * object ID (if HEAP_HASOID is set in t_infomask)
70 * We store five "virtual" fields Xmin, Cmin, Xmax, Cmax, and Xvac in three
71 * physical fields. Xmin and Xmax are always really stored, but Cmin, Cmax
72 * and Xvac share a field. This works because we know that Cmin and Cmax
73 * are only interesting for the lifetime of the inserting and deleting
74 * transaction respectively. If a tuple is inserted and deleted in the same
75 * transaction, we store a "combo" command id that can be mapped to the real
76 * cmin and cmax, but only by use of local state within the originating
77 * backend. See combocid.c for more details. Meanwhile, Xvac is only set by
78 * old-style VACUUM FULL, which does not have any command sub-structure and so
79 * does not need either Cmin or Cmax. (This requires that old-style VACUUM
80 * FULL never try to move a tuple whose Cmin or Cmax is still interesting,
81 * ie, an insert-in-progress or delete-in-progress tuple.)
83 * A word about t_ctid: whenever a new tuple is stored on disk, its t_ctid
84 * is initialized with its own TID (location). If the tuple is ever updated,
85 * its t_ctid is changed to point to the replacement version of the tuple.
86 * Thus, a tuple is the latest version of its row iff XMAX is invalid or
87 * t_ctid points to itself (in which case, if XMAX is valid, the tuple is
88 * either locked or deleted). One can follow the chain of t_ctid links
89 * to find the newest version of the row. Beware however that VACUUM might
90 * erase the pointed-to (newer) tuple before erasing the pointing (older)
91 * tuple. Hence, when following a t_ctid link, it is necessary to check
92 * to see if the referenced slot is empty or contains an unrelated tuple.
93 * Check that the referenced tuple has XMIN equal to the referencing tuple's
94 * XMAX to verify that it is actually the descendant version and not an
95 * unrelated tuple stored into a slot recently freed by VACUUM. If either
96 * check fails, one may assume that there is no live descendant version.
98 * Following the fixed header fields, the nulls bitmap is stored (beginning
99 * at t_bits). The bitmap is *not* stored if t_infomask shows that there
100 * are no nulls in the tuple. If an OID field is present (as indicated by
101 * t_infomask), then it is stored just before the user data, which begins at
102 * the offset shown by t_hoff. Note that t_hoff must be a multiple of
106 typedef struct HeapTupleFields
108 TransactionId t_xmin; /* inserting xact ID */
109 TransactionId t_xmax; /* deleting or locking xact ID */
113 CommandId t_cid; /* inserting or deleting command ID, or both */
114 TransactionId t_xvac; /* old-style VACUUM FULL xact ID */
118 typedef struct DatumTupleFields
120 int32 datum_len_; /* varlena header (do not touch directly!) */
122 int32 datum_typmod; /* -1, or identifier of a record type */
124 Oid datum_typeid; /* composite type OID, or RECORDOID */
127 * Note: field ordering is chosen with thought that Oid might someday
132 struct HeapTupleHeaderData
136 HeapTupleFields t_heap;
137 DatumTupleFields t_datum;
140 ItemPointerData t_ctid; /* current TID of this or newer tuple */
142 /* Fields below here must match MinimalTupleData! */
144 uint16 t_infomask2; /* number of attributes + various flags */
146 uint16 t_infomask; /* various flag bits, see below */
148 uint8 t_hoff; /* sizeof header incl. bitmap, padding */
150 /* ^ - 23 bytes - ^ */
152 bits8 t_bits[1]; /* bitmap of NULLs -- VARIABLE LENGTH */
154 /* MORE DATA FOLLOWS AT END OF STRUCT */
157 /* typedef appears in tupbasics.h */
160 * information stored in t_infomask:
162 #define HEAP_HASNULL 0x0001 /* has null attribute(s) */
163 #define HEAP_HASVARWIDTH 0x0002 /* has variable-width attribute(s) */
164 #define HEAP_HASEXTERNAL 0x0004 /* has external stored attribute(s) */
165 #define HEAP_HASOID 0x0008 /* has an object-id field */
166 #define HEAP_XMAX_KEYSHR_LOCK 0x0010 /* xmax is a key-shared locker */
167 #define HEAP_COMBOCID 0x0020 /* t_cid is a combo cid */
168 #define HEAP_XMAX_EXCL_LOCK 0x0040 /* xmax is exclusive locker */
169 #define HEAP_XMAX_LOCK_ONLY 0x0080 /* xmax, if valid, is only a locker */
171 /* xmax is a shared locker */
172 #define HEAP_XMAX_SHR_LOCK (HEAP_XMAX_EXCL_LOCK | HEAP_XMAX_KEYSHR_LOCK)
174 #define HEAP_LOCK_MASK (HEAP_XMAX_SHR_LOCK | HEAP_XMAX_EXCL_LOCK | \
175 HEAP_XMAX_KEYSHR_LOCK)
176 #define HEAP_XMIN_COMMITTED 0x0100 /* t_xmin committed */
177 #define HEAP_XMIN_INVALID 0x0200 /* t_xmin invalid/aborted */
178 #define HEAP_XMAX_COMMITTED 0x0400 /* t_xmax committed */
179 #define HEAP_XMAX_INVALID 0x0800 /* t_xmax invalid/aborted */
180 #define HEAP_XMAX_IS_MULTI 0x1000 /* t_xmax is a MultiXactId */
181 #define HEAP_UPDATED 0x2000 /* this is UPDATEd version of row */
182 #define HEAP_MOVED_OFF 0x4000 /* moved to another place by pre-9.0
183 * VACUUM FULL; kept for binary
185 #define HEAP_MOVED_IN 0x8000 /* moved from another place by pre-9.0
186 * VACUUM FULL; kept for binary
188 #define HEAP_MOVED (HEAP_MOVED_OFF | HEAP_MOVED_IN)
190 #define HEAP_XACT_MASK 0xFFF0 /* visibility-related bits */
193 * A tuple is only locked (i.e. not updated by its Xmax) if the
194 * HEAP_XMAX_LOCK_ONLY bit is set; or, for pg_upgrade's sake, if the Xmax is
195 * not a multi and the EXCL_LOCK bit is set.
197 * See also HeapTupleHeaderIsOnlyLocked, which also checks for a possible
198 * aborted updater transaction.
200 * Beware of multiple evaluations of the argument.
202 #define HEAP_XMAX_IS_LOCKED_ONLY(infomask) \
203 (((infomask) & HEAP_XMAX_LOCK_ONLY) || \
204 (((infomask) & (HEAP_XMAX_IS_MULTI | HEAP_LOCK_MASK)) == HEAP_XMAX_EXCL_LOCK))
207 * Use these to test whether a particular lock is applied to a tuple
209 #define HEAP_XMAX_IS_SHR_LOCKED(infomask) \
210 (((infomask) & HEAP_LOCK_MASK) == HEAP_XMAX_SHR_LOCK)
211 #define HEAP_XMAX_IS_EXCL_LOCKED(infomask) \
212 (((infomask) & HEAP_LOCK_MASK) == HEAP_XMAX_EXCL_LOCK)
213 #define HEAP_XMAX_IS_KEYSHR_LOCKED(infomask) \
214 (((infomask) & HEAP_LOCK_MASK) == HEAP_XMAX_KEYSHR_LOCK)
216 /* turn these all off when Xmax is to change */
217 #define HEAP_XMAX_BITS (HEAP_XMAX_COMMITTED | HEAP_XMAX_INVALID | \
218 HEAP_XMAX_IS_MULTI | HEAP_LOCK_MASK | HEAP_XMAX_LOCK_ONLY)
221 * information stored in t_infomask2:
223 #define HEAP_NATTS_MASK 0x07FF /* 11 bits for number of attributes */
224 /* bits 0x1800 are available */
225 #define HEAP_KEYS_UPDATED 0x2000 /* tuple was updated and key cols
226 * modified, or tuple deleted */
227 #define HEAP_HOT_UPDATED 0x4000 /* tuple was HOT-updated */
228 #define HEAP_ONLY_TUPLE 0x8000 /* this is heap-only tuple */
230 #define HEAP2_XACT_MASK 0xE000 /* visibility-related bits */
233 * HEAP_TUPLE_HAS_MATCH is a temporary flag used during hash joins. It is
234 * only used in tuples that are in the hash table, and those don't need
235 * any visibility information, so we can overlay it on a visibility flag
236 * instead of using up a dedicated bit.
238 #define HEAP_TUPLE_HAS_MATCH HEAP_ONLY_TUPLE /* tuple has a join match */
241 * HeapTupleHeader accessor macros
243 * Note: beware of multiple evaluations of "tup" argument. But the Set
244 * macros evaluate their other argument only once.
247 #define HeapTupleHeaderGetXmin(tup) \
249 (tup)->t_choice.t_heap.t_xmin \
252 #define HeapTupleHeaderSetXmin(tup, xid) \
254 (tup)->t_choice.t_heap.t_xmin = (xid) \
258 * HeapTupleHeaderGetRawXmax gets you the raw Xmax field. To find out the Xid
259 * that updated a tuple, you might need to resolve the MultiXactId if certain
260 * bits are set. HeapTupleHeaderGetUpdateXid checks those bits and takes care
261 * to resolve the MultiXactId if necessary. This might involve multixact I/O,
262 * so it should only be used if absolutely necessary.
264 #define HeapTupleHeaderGetUpdateXid(tup) \
266 (!((tup)->t_infomask & HEAP_XMAX_INVALID) && \
267 ((tup)->t_infomask & HEAP_XMAX_IS_MULTI) && \
268 !((tup)->t_infomask & HEAP_XMAX_LOCK_ONLY)) ? \
269 HeapTupleGetUpdateXid(tup) \
271 HeapTupleHeaderGetRawXmax(tup) \
274 #define HeapTupleHeaderGetRawXmax(tup) \
276 (tup)->t_choice.t_heap.t_xmax \
279 #define HeapTupleHeaderSetXmax(tup, xid) \
281 (tup)->t_choice.t_heap.t_xmax = (xid) \
285 * HeapTupleHeaderGetRawCommandId will give you what's in the header whether
286 * it is useful or not. Most code should use HeapTupleHeaderGetCmin or
287 * HeapTupleHeaderGetCmax instead, but note that those Assert that you can
288 * get a legitimate result, ie you are in the originating transaction!
290 #define HeapTupleHeaderGetRawCommandId(tup) \
292 (tup)->t_choice.t_heap.t_field3.t_cid \
295 /* SetCmin is reasonably simple since we never need a combo CID */
296 #define HeapTupleHeaderSetCmin(tup, cid) \
298 Assert(!((tup)->t_infomask & HEAP_MOVED)); \
299 (tup)->t_choice.t_heap.t_field3.t_cid = (cid); \
300 (tup)->t_infomask &= ~HEAP_COMBOCID; \
303 /* SetCmax must be used after HeapTupleHeaderAdjustCmax; see combocid.c */
304 #define HeapTupleHeaderSetCmax(tup, cid, iscombo) \
306 Assert(!((tup)->t_infomask & HEAP_MOVED)); \
307 (tup)->t_choice.t_heap.t_field3.t_cid = (cid); \
309 (tup)->t_infomask |= HEAP_COMBOCID; \
311 (tup)->t_infomask &= ~HEAP_COMBOCID; \
314 #define HeapTupleHeaderGetXvac(tup) \
316 ((tup)->t_infomask & HEAP_MOVED) ? \
317 (tup)->t_choice.t_heap.t_field3.t_xvac \
319 InvalidTransactionId \
322 #define HeapTupleHeaderSetXvac(tup, xid) \
324 Assert((tup)->t_infomask & HEAP_MOVED); \
325 (tup)->t_choice.t_heap.t_field3.t_xvac = (xid); \
328 #define HeapTupleHeaderGetDatumLength(tup) \
331 #define HeapTupleHeaderSetDatumLength(tup, len) \
332 SET_VARSIZE(tup, len)
334 #define HeapTupleHeaderGetTypeId(tup) \
336 (tup)->t_choice.t_datum.datum_typeid \
339 #define HeapTupleHeaderSetTypeId(tup, typeid) \
341 (tup)->t_choice.t_datum.datum_typeid = (typeid) \
344 #define HeapTupleHeaderGetTypMod(tup) \
346 (tup)->t_choice.t_datum.datum_typmod \
349 #define HeapTupleHeaderSetTypMod(tup, typmod) \
351 (tup)->t_choice.t_datum.datum_typmod = (typmod) \
354 #define HeapTupleHeaderGetOid(tup) \
356 ((tup)->t_infomask & HEAP_HASOID) ? \
357 *((Oid *) ((char *)(tup) + (tup)->t_hoff - sizeof(Oid))) \
362 #define HeapTupleHeaderSetOid(tup, oid) \
364 Assert((tup)->t_infomask & HEAP_HASOID); \
365 *((Oid *) ((char *)(tup) + (tup)->t_hoff - sizeof(Oid))) = (oid); \
369 * Note that we stop considering a tuple HOT-updated as soon as it is known
370 * aborted or the would-be updating transaction is known aborted. For best
371 * efficiency, check tuple visibility before using this macro, so that the
372 * INVALID bits will be as up to date as possible.
374 #define HeapTupleHeaderIsHotUpdated(tup) \
376 ((tup)->t_infomask2 & HEAP_HOT_UPDATED) != 0 && \
377 ((tup)->t_infomask & (HEAP_XMIN_INVALID | HEAP_XMAX_INVALID)) == 0 \
380 #define HeapTupleHeaderSetHotUpdated(tup) \
382 (tup)->t_infomask2 |= HEAP_HOT_UPDATED \
385 #define HeapTupleHeaderClearHotUpdated(tup) \
387 (tup)->t_infomask2 &= ~HEAP_HOT_UPDATED \
390 #define HeapTupleHeaderIsHeapOnly(tup) \
392 (tup)->t_infomask2 & HEAP_ONLY_TUPLE \
395 #define HeapTupleHeaderSetHeapOnly(tup) \
397 (tup)->t_infomask2 |= HEAP_ONLY_TUPLE \
400 #define HeapTupleHeaderClearHeapOnly(tup) \
402 (tup)->t_infomask2 &= ~HEAP_ONLY_TUPLE \
405 #define HeapTupleHeaderHasMatch(tup) \
407 (tup)->t_infomask2 & HEAP_TUPLE_HAS_MATCH \
410 #define HeapTupleHeaderSetMatch(tup) \
412 (tup)->t_infomask2 |= HEAP_TUPLE_HAS_MATCH \
415 #define HeapTupleHeaderClearMatch(tup) \
417 (tup)->t_infomask2 &= ~HEAP_TUPLE_HAS_MATCH \
420 #define HeapTupleHeaderGetNatts(tup) \
421 ((tup)->t_infomask2 & HEAP_NATTS_MASK)
423 #define HeapTupleHeaderSetNatts(tup, natts) \
425 (tup)->t_infomask2 = ((tup)->t_infomask2 & ~HEAP_NATTS_MASK) | (natts) \
431 * Computes size of null bitmap given number of data columns.
433 #define BITMAPLEN(NATTS) (((int)(NATTS) + 7) / 8)
436 * MaxHeapTupleSize is the maximum allowed size of a heap tuple, including
437 * header and MAXALIGN alignment padding. Basically it's BLCKSZ minus the
438 * other stuff that has to be on a disk page. Since heap pages use no
439 * "special space", there's no deduction for that.
441 * NOTE: we allow for the ItemId that must point to the tuple, ensuring that
442 * an otherwise-empty page can indeed hold a tuple of this size. Because
443 * ItemIds and tuples have different alignment requirements, don't assume that
444 * you can, say, fit 2 tuples of size MaxHeapTupleSize/2 on the same page.
446 #define MaxHeapTupleSize (BLCKSZ - MAXALIGN(SizeOfPageHeaderData + sizeof(ItemIdData)))
449 * MaxHeapTuplesPerPage is an upper bound on the number of tuples that can
450 * fit on one heap page. (Note that indexes could have more, because they
451 * use a smaller tuple header.) We arrive at the divisor because each tuple
452 * must be maxaligned, and it must have an associated item pointer.
454 * Note: with HOT, there could theoretically be more line pointers (not actual
455 * tuples) than this on a heap page. However we constrain the number of line
456 * pointers to this anyway, to avoid excessive line-pointer bloat and not
457 * require increases in the size of work arrays.
459 #define MaxHeapTuplesPerPage \
460 ((int) ((BLCKSZ - SizeOfPageHeaderData) / \
461 (MAXALIGN(offsetof(HeapTupleHeaderData, t_bits)) + sizeof(ItemIdData))))
464 * MaxAttrSize is a somewhat arbitrary upper limit on the declared size of
465 * data fields of char(n) and similar types. It need not have anything
466 * directly to do with the *actual* upper limit of varlena values, which
467 * is currently 1Gb (see TOAST structures in postgres.h). I've set it
468 * at 10Mb which seems like a reasonable number --- tgl 8/6/00.
470 #define MaxAttrSize (10 * 1024 * 1024)
474 * MinimalTuple is an alternative representation that is used for transient
475 * tuples inside the executor, in places where transaction status information
476 * is not required, the tuple rowtype is known, and shaving off a few bytes
477 * is worthwhile because we need to store many tuples. The representation
478 * is chosen so that tuple access routines can work with either full or
479 * minimal tuples via a HeapTupleData pointer structure. The access routines
480 * see no difference, except that they must not access the transaction status
481 * or t_ctid fields because those aren't there.
483 * For the most part, MinimalTuples should be accessed via TupleTableSlot
484 * routines. These routines will prevent access to the "system columns"
485 * and thereby prevent accidental use of the nonexistent fields.
487 * MinimalTupleData contains a length word, some padding, and fields matching
488 * HeapTupleHeaderData beginning with t_infomask2. The padding is chosen so
489 * that offsetof(t_infomask2) is the same modulo MAXIMUM_ALIGNOF in both
490 * structs. This makes data alignment rules equivalent in both cases.
492 * When a minimal tuple is accessed via a HeapTupleData pointer, t_data is
493 * set to point MINIMAL_TUPLE_OFFSET bytes before the actual start of the
494 * minimal tuple --- that is, where a full tuple matching the minimal tuple's
495 * data would start. This trick is what makes the structs seem equivalent.
497 * Note that t_hoff is computed the same as in a full tuple, hence it includes
498 * the MINIMAL_TUPLE_OFFSET distance. t_len does not include that, however.
500 * MINIMAL_TUPLE_DATA_OFFSET is the offset to the first useful (non-pad) data
501 * other than the length word. tuplesort.c and tuplestore.c use this to avoid
502 * writing the padding to disk.
504 #define MINIMAL_TUPLE_OFFSET \
505 ((offsetof(HeapTupleHeaderData, t_infomask2) - sizeof(uint32)) / MAXIMUM_ALIGNOF * MAXIMUM_ALIGNOF)
506 #define MINIMAL_TUPLE_PADDING \
507 ((offsetof(HeapTupleHeaderData, t_infomask2) - sizeof(uint32)) % MAXIMUM_ALIGNOF)
508 #define MINIMAL_TUPLE_DATA_OFFSET \
509 offsetof(MinimalTupleData, t_infomask2)
511 struct MinimalTupleData
513 uint32 t_len; /* actual length of minimal tuple */
515 char mt_padding[MINIMAL_TUPLE_PADDING];
517 /* Fields below here must match HeapTupleHeaderData! */
519 uint16 t_infomask2; /* number of attributes + various flags */
521 uint16 t_infomask; /* various flag bits, see below */
523 uint8 t_hoff; /* sizeof header incl. bitmap, padding */
525 /* ^ - 23 bytes - ^ */
527 bits8 t_bits[1]; /* bitmap of NULLs -- VARIABLE LENGTH */
529 /* MORE DATA FOLLOWS AT END OF STRUCT */
532 /* typedef appears in htup.h */
536 * GETSTRUCT - given a HeapTuple pointer, return address of the user data
538 #define GETSTRUCT(TUP) ((char *) ((TUP)->t_data) + (TUP)->t_data->t_hoff)
541 * Accessor macros to be used with HeapTuple pointers.
544 #define HeapTupleHasNulls(tuple) \
545 (((tuple)->t_data->t_infomask & HEAP_HASNULL) != 0)
547 #define HeapTupleNoNulls(tuple) \
548 (!((tuple)->t_data->t_infomask & HEAP_HASNULL))
550 #define HeapTupleHasVarWidth(tuple) \
551 (((tuple)->t_data->t_infomask & HEAP_HASVARWIDTH) != 0)
553 #define HeapTupleAllFixed(tuple) \
554 (!((tuple)->t_data->t_infomask & HEAP_HASVARWIDTH))
556 #define HeapTupleHasExternal(tuple) \
557 (((tuple)->t_data->t_infomask & HEAP_HASEXTERNAL) != 0)
559 #define HeapTupleIsHotUpdated(tuple) \
560 HeapTupleHeaderIsHotUpdated((tuple)->t_data)
562 #define HeapTupleSetHotUpdated(tuple) \
563 HeapTupleHeaderSetHotUpdated((tuple)->t_data)
565 #define HeapTupleClearHotUpdated(tuple) \
566 HeapTupleHeaderClearHotUpdated((tuple)->t_data)
568 #define HeapTupleIsHeapOnly(tuple) \
569 HeapTupleHeaderIsHeapOnly((tuple)->t_data)
571 #define HeapTupleSetHeapOnly(tuple) \
572 HeapTupleHeaderSetHeapOnly((tuple)->t_data)
574 #define HeapTupleClearHeapOnly(tuple) \
575 HeapTupleHeaderClearHeapOnly((tuple)->t_data)
577 #define HeapTupleGetOid(tuple) \
578 HeapTupleHeaderGetOid((tuple)->t_data)
580 #define HeapTupleSetOid(tuple, oid) \
581 HeapTupleHeaderSetOid((tuple)->t_data, (oid))
587 * Fetch a user attribute's value as a Datum (might be either a
588 * value, or a pointer into the data area of the tuple).
590 * This must not be used when a system attribute might be requested.
591 * Furthermore, the passed attnum MUST be valid. Use heap_getattr()
592 * instead, if in doubt.
594 * This gets called many times, so we macro the cacheable and NULL
595 * lookups, and call nocachegetattr() for the rest.
599 #if !defined(DISABLE_COMPLEX_MACRO)
601 #define fastgetattr(tup, attnum, tupleDesc, isnull) \
603 AssertMacro((attnum) > 0), \
604 (*(isnull) = false), \
605 HeapTupleNoNulls(tup) ? \
607 (tupleDesc)->attrs[(attnum)-1]->attcacheoff >= 0 ? \
609 fetchatt((tupleDesc)->attrs[(attnum)-1], \
610 (char *) (tup)->t_data + (tup)->t_data->t_hoff + \
611 (tupleDesc)->attrs[(attnum)-1]->attcacheoff) \
614 nocachegetattr((tup), (attnum), (tupleDesc)) \
618 att_isnull((attnum)-1, (tup)->t_data->t_bits) ? \
620 (*(isnull) = true), \
625 nocachegetattr((tup), (attnum), (tupleDesc)) \
629 #else /* defined(DISABLE_COMPLEX_MACRO) */
631 extern Datum fastgetattr(HeapTuple tup, int attnum, TupleDesc tupleDesc,
633 #endif /* defined(DISABLE_COMPLEX_MACRO) */
639 * Extract an attribute of a heap tuple and return it as a Datum.
640 * This works for either system or user attributes. The given attnum
641 * is properly range-checked.
643 * If the field in question has a NULL value, we return a zero Datum
644 * and set *isnull == true. Otherwise, we set *isnull == false.
646 * <tup> is the pointer to the heap tuple. <attnum> is the attribute
647 * number of the column (field) caller wants. <tupleDesc> is a
648 * pointer to the structure describing the row and all its fields.
651 #define heap_getattr(tup, attnum, tupleDesc, isnull) \
655 ((attnum) > (int) HeapTupleHeaderGetNatts((tup)->t_data)) ? \
657 (*(isnull) = true), \
661 fastgetattr((tup), (attnum), (tupleDesc), (isnull)) \
664 heap_getsysattr((tup), (attnum), (tupleDesc), (isnull)) \
668 /* prototypes for functions in common/heaptuple.c */
669 extern Size heap_compute_data_size(TupleDesc tupleDesc,
670 Datum *values, bool *isnull);
671 extern void heap_fill_tuple(TupleDesc tupleDesc,
672 Datum *values, bool *isnull,
673 char *data, Size data_size,
674 uint16 *infomask, bits8 *bit);
675 extern bool heap_attisnull(HeapTuple tup, int attnum);
676 extern Datum nocachegetattr(HeapTuple tup, int attnum,
678 extern Datum heap_getsysattr(HeapTuple tup, int attnum, TupleDesc tupleDesc,
680 extern HeapTuple heap_copytuple(HeapTuple tuple);
681 extern void heap_copytuple_with_tuple(HeapTuple src, HeapTuple dest);
682 extern HeapTuple heap_form_tuple(TupleDesc tupleDescriptor,
683 Datum *values, bool *isnull);
684 extern HeapTuple heap_modify_tuple(HeapTuple tuple,
689 extern void heap_deform_tuple(HeapTuple tuple, TupleDesc tupleDesc,
690 Datum *values, bool *isnull);
692 /* these three are deprecated versions of the three above: */
693 extern HeapTuple heap_formtuple(TupleDesc tupleDescriptor,
694 Datum *values, char *nulls);
695 extern HeapTuple heap_modifytuple(HeapTuple tuple,
700 extern void heap_deformtuple(HeapTuple tuple, TupleDesc tupleDesc,
701 Datum *values, char *nulls);
702 extern void heap_freetuple(HeapTuple htup);
703 extern MinimalTuple heap_form_minimal_tuple(TupleDesc tupleDescriptor,
704 Datum *values, bool *isnull);
705 extern void heap_free_minimal_tuple(MinimalTuple mtup);
706 extern MinimalTuple heap_copy_minimal_tuple(MinimalTuple mtup);
707 extern HeapTuple heap_tuple_from_minimal_tuple(MinimalTuple mtup);
708 extern MinimalTuple minimal_tuple_from_heap_tuple(HeapTuple htup);
710 #endif /* HTUP_DETAILS_H */