1 /*-------------------------------------------------------------------------
4 * POSTGRES heap tuple definitions.
7 * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
10 * src/include/access/htup.h
12 *-------------------------------------------------------------------------
17 #include "access/tupdesc.h"
18 #include "access/tupmacs.h"
19 #include "storage/bufpage.h"
20 #include "storage/itemptr.h"
21 #include "storage/relfilenode.h"
24 * MaxTupleAttributeNumber limits the number of (user) columns in a tuple.
25 * The key limit on this value is that the size of the fixed overhead for
26 * a tuple, plus the size of the null-values bitmap (at 1 bit per column),
27 * plus MAXALIGN alignment, must fit into t_hoff which is uint8. On most
28 * machines the upper limit without making t_hoff wider would be a little
29 * over 1700. We use round numbers here and for MaxHeapAttributeNumber
30 * so that alterations in HeapTupleHeaderData layout won't change the
31 * supported max number of columns.
33 #define MaxTupleAttributeNumber 1664 /* 8 * 208 */
36 * MaxHeapAttributeNumber limits the number of (user) columns in a table.
37 * This should be somewhat less than MaxTupleAttributeNumber. It must be
38 * at least one less, else we will fail to do UPDATEs on a maximal-width
39 * table (because UPDATE has to form working tuples that include CTID).
40 * In practice we want some additional daylight so that we can gracefully
41 * support operations that add hidden "resjunk" columns, for example
42 * SELECT * FROM wide_table ORDER BY foo, bar, baz.
43 * In any case, depending on column data types you will likely be running
44 * into the disk-block-based limit on overall tuple size if you have more
45 * than a thousand or so columns. TOAST won't help.
47 #define MaxHeapAttributeNumber 1600 /* 8 * 200 */
50 * Heap tuple header. To avoid wasting space, the fields should be
51 * laid out in such a way as to avoid structure padding.
53 * Datums of composite types (row types) share the same general structure
54 * as on-disk tuples, so that the same routines can be used to build and
55 * examine them. However the requirements are slightly different: a Datum
56 * does not need any transaction visibility information, and it does need
57 * a length word and some embedded type information. We can achieve this
58 * by overlaying the xmin/cmin/xmax/cmax/xvac fields of a heap tuple
59 * with the fields needed in the Datum case. Typically, all tuples built
60 * in-memory will be initialized with the Datum fields; but when a tuple is
61 * about to be inserted in a table, the transaction fields will be filled,
62 * overwriting the datum fields.
64 * The overall structure of a heap tuple looks like:
65 * fixed fields (HeapTupleHeaderData struct)
66 * nulls bitmap (if HEAP_HASNULL is set in t_infomask)
67 * alignment padding (as needed to make user data MAXALIGN'd)
68 * object ID (if HEAP_HASOID is set in t_infomask)
71 * We store five "virtual" fields Xmin, Cmin, Xmax, Cmax, and Xvac in three
72 * physical fields. Xmin and Xmax are always really stored, but Cmin, Cmax
73 * and Xvac share a field. This works because we know that Cmin and Cmax
74 * are only interesting for the lifetime of the inserting and deleting
75 * transaction respectively. If a tuple is inserted and deleted in the same
76 * transaction, we store a "combo" command id that can be mapped to the real
77 * cmin and cmax, but only by use of local state within the originating
78 * backend. See combocid.c for more details. Meanwhile, Xvac is only set by
79 * old-style VACUUM FULL, which does not have any command sub-structure and so
80 * does not need either Cmin or Cmax. (This requires that old-style VACUUM
81 * FULL never try to move a tuple whose Cmin or Cmax is still interesting,
82 * ie, an insert-in-progress or delete-in-progress tuple.)
84 * A word about t_ctid: whenever a new tuple is stored on disk, its t_ctid
85 * is initialized with its own TID (location). If the tuple is ever updated,
86 * its t_ctid is changed to point to the replacement version of the tuple.
87 * Thus, a tuple is the latest version of its row iff XMAX is invalid or
88 * t_ctid points to itself (in which case, if XMAX is valid, the tuple is
89 * either locked or deleted). One can follow the chain of t_ctid links
90 * to find the newest version of the row. Beware however that VACUUM might
91 * erase the pointed-to (newer) tuple before erasing the pointing (older)
92 * tuple. Hence, when following a t_ctid link, it is necessary to check
93 * to see if the referenced slot is empty or contains an unrelated tuple.
94 * Check that the referenced tuple has XMIN equal to the referencing tuple's
95 * XMAX to verify that it is actually the descendant version and not an
96 * unrelated tuple stored into a slot recently freed by VACUUM. If either
97 * check fails, one may assume that there is no live descendant version.
99 * Following the fixed header fields, the nulls bitmap is stored (beginning
100 * at t_bits). The bitmap is *not* stored if t_infomask shows that there
101 * are no nulls in the tuple. If an OID field is present (as indicated by
102 * t_infomask), then it is stored just before the user data, which begins at
103 * the offset shown by t_hoff. Note that t_hoff must be a multiple of
107 typedef struct HeapTupleFields
109 TransactionId t_xmin; /* inserting xact ID */
110 TransactionId t_xmax; /* deleting or locking xact ID */
114 CommandId t_cid; /* inserting or deleting command ID, or both */
115 TransactionId t_xvac; /* old-style VACUUM FULL xact ID */
119 typedef struct DatumTupleFields
121 int32 datum_len_; /* varlena header (do not touch directly!) */
123 int32 datum_typmod; /* -1, or identifier of a record type */
125 Oid datum_typeid; /* composite type OID, or RECORDOID */
128 * Note: field ordering is chosen with thought that Oid might someday
133 typedef struct HeapTupleHeaderData
137 HeapTupleFields t_heap;
138 DatumTupleFields t_datum;
141 ItemPointerData t_ctid; /* current TID of this or newer tuple */
143 /* Fields below here must match MinimalTupleData! */
145 uint16 t_infomask2; /* number of attributes + various flags */
147 uint16 t_infomask; /* various flag bits, see below */
149 uint8 t_hoff; /* sizeof header incl. bitmap, padding */
151 /* ^ - 23 bytes - ^ */
153 bits8 t_bits[1]; /* bitmap of NULLs -- VARIABLE LENGTH */
155 /* MORE DATA FOLLOWS AT END OF STRUCT */
156 } HeapTupleHeaderData;
158 typedef HeapTupleHeaderData *HeapTupleHeader;
161 * information stored in t_infomask:
163 #define HEAP_HASNULL 0x0001 /* has null attribute(s) */
164 #define HEAP_HASVARWIDTH 0x0002 /* has variable-width attribute(s) */
165 #define HEAP_HASEXTERNAL 0x0004 /* has external stored attribute(s) */
166 #define HEAP_HASOID 0x0008 /* has an object-id field */
167 /* bit 0x0010 is available */
168 #define HEAP_COMBOCID 0x0020 /* t_cid is a combo cid */
169 #define HEAP_XMAX_EXCL_LOCK 0x0040 /* xmax is exclusive locker */
170 #define HEAP_XMAX_SHARED_LOCK 0x0080 /* xmax is shared locker */
171 /* if either LOCK bit is set, xmax hasn't deleted the tuple, only locked it */
172 #define HEAP_IS_LOCKED (HEAP_XMAX_EXCL_LOCK | HEAP_XMAX_SHARED_LOCK)
173 #define HEAP_XMIN_COMMITTED 0x0100 /* t_xmin committed */
174 #define HEAP_XMIN_INVALID 0x0200 /* t_xmin invalid/aborted */
175 #define HEAP_XMAX_COMMITTED 0x0400 /* t_xmax committed */
176 #define HEAP_XMAX_INVALID 0x0800 /* t_xmax invalid/aborted */
177 #define HEAP_XMAX_IS_MULTI 0x1000 /* t_xmax is a MultiXactId */
178 #define HEAP_UPDATED 0x2000 /* this is UPDATEd version of row */
179 #define HEAP_MOVED_OFF 0x4000 /* moved to another place by pre-9.0
180 * VACUUM FULL; kept for binary
182 #define HEAP_MOVED_IN 0x8000 /* moved from another place by pre-9.0
183 * VACUUM FULL; kept for binary
185 #define HEAP_MOVED (HEAP_MOVED_OFF | HEAP_MOVED_IN)
187 #define HEAP_XACT_MASK 0xFFE0 /* visibility-related bits */
190 * information stored in t_infomask2:
192 #define HEAP_NATTS_MASK 0x07FF /* 11 bits for number of attributes */
193 /* bits 0x3800 are available */
194 #define HEAP_HOT_UPDATED 0x4000 /* tuple was HOT-updated */
195 #define HEAP_ONLY_TUPLE 0x8000 /* this is heap-only tuple */
197 #define HEAP2_XACT_MASK 0xC000 /* visibility-related bits */
200 * HEAP_TUPLE_HAS_MATCH is a temporary flag used during hash joins. It is
201 * only used in tuples that are in the hash table, and those don't need
202 * any visibility information, so we can overlay it on a visibility flag
203 * instead of using up a dedicated bit.
205 #define HEAP_TUPLE_HAS_MATCH HEAP_ONLY_TUPLE /* tuple has a join match */
208 * HeapTupleHeader accessor macros
210 * Note: beware of multiple evaluations of "tup" argument. But the Set
211 * macros evaluate their other argument only once.
214 #define HeapTupleHeaderGetXmin(tup) \
216 (tup)->t_choice.t_heap.t_xmin \
219 #define HeapTupleHeaderSetXmin(tup, xid) \
221 (tup)->t_choice.t_heap.t_xmin = (xid) \
224 #define HeapTupleHeaderGetXmax(tup) \
226 (tup)->t_choice.t_heap.t_xmax \
229 #define HeapTupleHeaderSetXmax(tup, xid) \
231 (tup)->t_choice.t_heap.t_xmax = (xid) \
235 * HeapTupleHeaderGetRawCommandId will give you what's in the header whether
236 * it is useful or not. Most code should use HeapTupleHeaderGetCmin or
237 * HeapTupleHeaderGetCmax instead, but note that those Assert that you can
238 * get a legitimate result, ie you are in the originating transaction!
240 #define HeapTupleHeaderGetRawCommandId(tup) \
242 (tup)->t_choice.t_heap.t_field3.t_cid \
245 /* SetCmin is reasonably simple since we never need a combo CID */
246 #define HeapTupleHeaderSetCmin(tup, cid) \
248 Assert(!((tup)->t_infomask & HEAP_MOVED)); \
249 (tup)->t_choice.t_heap.t_field3.t_cid = (cid); \
250 (tup)->t_infomask &= ~HEAP_COMBOCID; \
253 /* SetCmax must be used after HeapTupleHeaderAdjustCmax; see combocid.c */
254 #define HeapTupleHeaderSetCmax(tup, cid, iscombo) \
256 Assert(!((tup)->t_infomask & HEAP_MOVED)); \
257 (tup)->t_choice.t_heap.t_field3.t_cid = (cid); \
259 (tup)->t_infomask |= HEAP_COMBOCID; \
261 (tup)->t_infomask &= ~HEAP_COMBOCID; \
264 #define HeapTupleHeaderGetXvac(tup) \
266 ((tup)->t_infomask & HEAP_MOVED) ? \
267 (tup)->t_choice.t_heap.t_field3.t_xvac \
269 InvalidTransactionId \
272 #define HeapTupleHeaderSetXvac(tup, xid) \
274 Assert((tup)->t_infomask & HEAP_MOVED); \
275 (tup)->t_choice.t_heap.t_field3.t_xvac = (xid); \
278 #define HeapTupleHeaderGetDatumLength(tup) \
281 #define HeapTupleHeaderSetDatumLength(tup, len) \
282 SET_VARSIZE(tup, len)
284 #define HeapTupleHeaderGetTypeId(tup) \
286 (tup)->t_choice.t_datum.datum_typeid \
289 #define HeapTupleHeaderSetTypeId(tup, typeid) \
291 (tup)->t_choice.t_datum.datum_typeid = (typeid) \
294 #define HeapTupleHeaderGetTypMod(tup) \
296 (tup)->t_choice.t_datum.datum_typmod \
299 #define HeapTupleHeaderSetTypMod(tup, typmod) \
301 (tup)->t_choice.t_datum.datum_typmod = (typmod) \
304 #define HeapTupleHeaderGetOid(tup) \
306 ((tup)->t_infomask & HEAP_HASOID) ? \
307 *((Oid *) ((char *)(tup) + (tup)->t_hoff - sizeof(Oid))) \
312 #define HeapTupleHeaderSetOid(tup, oid) \
314 Assert((tup)->t_infomask & HEAP_HASOID); \
315 *((Oid *) ((char *)(tup) + (tup)->t_hoff - sizeof(Oid))) = (oid); \
319 * Note that we stop considering a tuple HOT-updated as soon as it is known
320 * aborted or the would-be updating transaction is known aborted. For best
321 * efficiency, check tuple visibility before using this macro, so that the
322 * INVALID bits will be as up to date as possible.
324 #define HeapTupleHeaderIsHotUpdated(tup) \
326 ((tup)->t_infomask2 & HEAP_HOT_UPDATED) != 0 && \
327 ((tup)->t_infomask & (HEAP_XMIN_INVALID | HEAP_XMAX_INVALID)) == 0 \
330 #define HeapTupleHeaderSetHotUpdated(tup) \
332 (tup)->t_infomask2 |= HEAP_HOT_UPDATED \
335 #define HeapTupleHeaderClearHotUpdated(tup) \
337 (tup)->t_infomask2 &= ~HEAP_HOT_UPDATED \
340 #define HeapTupleHeaderIsHeapOnly(tup) \
342 (tup)->t_infomask2 & HEAP_ONLY_TUPLE \
345 #define HeapTupleHeaderSetHeapOnly(tup) \
347 (tup)->t_infomask2 |= HEAP_ONLY_TUPLE \
350 #define HeapTupleHeaderClearHeapOnly(tup) \
352 (tup)->t_infomask2 &= ~HEAP_ONLY_TUPLE \
355 #define HeapTupleHeaderHasMatch(tup) \
357 (tup)->t_infomask2 & HEAP_TUPLE_HAS_MATCH \
360 #define HeapTupleHeaderSetMatch(tup) \
362 (tup)->t_infomask2 |= HEAP_TUPLE_HAS_MATCH \
365 #define HeapTupleHeaderClearMatch(tup) \
367 (tup)->t_infomask2 &= ~HEAP_TUPLE_HAS_MATCH \
370 #define HeapTupleHeaderGetNatts(tup) \
371 ((tup)->t_infomask2 & HEAP_NATTS_MASK)
373 #define HeapTupleHeaderSetNatts(tup, natts) \
375 (tup)->t_infomask2 = ((tup)->t_infomask2 & ~HEAP_NATTS_MASK) | (natts) \
381 * Computes size of null bitmap given number of data columns.
383 #define BITMAPLEN(NATTS) (((int)(NATTS) + 7) / 8)
386 * MaxHeapTupleSize is the maximum allowed size of a heap tuple, including
387 * header and MAXALIGN alignment padding. Basically it's BLCKSZ minus the
388 * other stuff that has to be on a disk page. Since heap pages use no
389 * "special space", there's no deduction for that.
391 * NOTE: we allow for the ItemId that must point to the tuple, ensuring that
392 * an otherwise-empty page can indeed hold a tuple of this size. Because
393 * ItemIds and tuples have different alignment requirements, don't assume that
394 * you can, say, fit 2 tuples of size MaxHeapTupleSize/2 on the same page.
396 #define MaxHeapTupleSize (BLCKSZ - MAXALIGN(SizeOfPageHeaderData + sizeof(ItemIdData)))
399 * MaxHeapTuplesPerPage is an upper bound on the number of tuples that can
400 * fit on one heap page. (Note that indexes could have more, because they
401 * use a smaller tuple header.) We arrive at the divisor because each tuple
402 * must be maxaligned, and it must have an associated item pointer.
404 * Note: with HOT, there could theoretically be more line pointers (not actual
405 * tuples) than this on a heap page. However we constrain the number of line
406 * pointers to this anyway, to avoid excessive line-pointer bloat and not
407 * require increases in the size of work arrays.
409 #define MaxHeapTuplesPerPage \
410 ((int) ((BLCKSZ - SizeOfPageHeaderData) / \
411 (MAXALIGN(offsetof(HeapTupleHeaderData, t_bits)) + sizeof(ItemIdData))))
414 * MaxAttrSize is a somewhat arbitrary upper limit on the declared size of
415 * data fields of char(n) and similar types. It need not have anything
416 * directly to do with the *actual* upper limit of varlena values, which
417 * is currently 1Gb (see TOAST structures in postgres.h). I've set it
418 * at 10Mb which seems like a reasonable number --- tgl 8/6/00.
420 #define MaxAttrSize (10 * 1024 * 1024)
424 * MinimalTuple is an alternative representation that is used for transient
425 * tuples inside the executor, in places where transaction status information
426 * is not required, the tuple rowtype is known, and shaving off a few bytes
427 * is worthwhile because we need to store many tuples. The representation
428 * is chosen so that tuple access routines can work with either full or
429 * minimal tuples via a HeapTupleData pointer structure. The access routines
430 * see no difference, except that they must not access the transaction status
431 * or t_ctid fields because those aren't there.
433 * For the most part, MinimalTuples should be accessed via TupleTableSlot
434 * routines. These routines will prevent access to the "system columns"
435 * and thereby prevent accidental use of the nonexistent fields.
437 * MinimalTupleData contains a length word, some padding, and fields matching
438 * HeapTupleHeaderData beginning with t_infomask2. The padding is chosen so
439 * that offsetof(t_infomask2) is the same modulo MAXIMUM_ALIGNOF in both
440 * structs. This makes data alignment rules equivalent in both cases.
442 * When a minimal tuple is accessed via a HeapTupleData pointer, t_data is
443 * set to point MINIMAL_TUPLE_OFFSET bytes before the actual start of the
444 * minimal tuple --- that is, where a full tuple matching the minimal tuple's
445 * data would start. This trick is what makes the structs seem equivalent.
447 * Note that t_hoff is computed the same as in a full tuple, hence it includes
448 * the MINIMAL_TUPLE_OFFSET distance. t_len does not include that, however.
450 * MINIMAL_TUPLE_DATA_OFFSET is the offset to the first useful (non-pad) data
451 * other than the length word. tuplesort.c and tuplestore.c use this to avoid
452 * writing the padding to disk.
454 #define MINIMAL_TUPLE_OFFSET \
455 ((offsetof(HeapTupleHeaderData, t_infomask2) - sizeof(uint32)) / MAXIMUM_ALIGNOF * MAXIMUM_ALIGNOF)
456 #define MINIMAL_TUPLE_PADDING \
457 ((offsetof(HeapTupleHeaderData, t_infomask2) - sizeof(uint32)) % MAXIMUM_ALIGNOF)
458 #define MINIMAL_TUPLE_DATA_OFFSET \
459 offsetof(MinimalTupleData, t_infomask2)
461 typedef struct MinimalTupleData
463 uint32 t_len; /* actual length of minimal tuple */
465 char mt_padding[MINIMAL_TUPLE_PADDING];
467 /* Fields below here must match HeapTupleHeaderData! */
469 uint16 t_infomask2; /* number of attributes + various flags */
471 uint16 t_infomask; /* various flag bits, see below */
473 uint8 t_hoff; /* sizeof header incl. bitmap, padding */
475 /* ^ - 23 bytes - ^ */
477 bits8 t_bits[1]; /* bitmap of NULLs -- VARIABLE LENGTH */
479 /* MORE DATA FOLLOWS AT END OF STRUCT */
482 typedef MinimalTupleData *MinimalTuple;
486 * HeapTupleData is an in-memory data structure that points to a tuple.
488 * There are several ways in which this data structure is used:
490 * * Pointer to a tuple in a disk buffer: t_data points directly into the
491 * buffer (which the code had better be holding a pin on, but this is not
492 * reflected in HeapTupleData itself).
494 * * Pointer to nothing: t_data is NULL. This is used as a failure indication
497 * * Part of a palloc'd tuple: the HeapTupleData itself and the tuple
498 * form a single palloc'd chunk. t_data points to the memory location
499 * immediately following the HeapTupleData struct (at offset HEAPTUPLESIZE).
500 * This is the output format of heap_form_tuple and related routines.
502 * * Separately allocated tuple: t_data points to a palloc'd chunk that
503 * is not adjacent to the HeapTupleData. (This case is deprecated since
504 * it's difficult to tell apart from case #1. It should be used only in
505 * limited contexts where the code knows that case #1 will never apply.)
507 * * Separately allocated minimal tuple: t_data points MINIMAL_TUPLE_OFFSET
508 * bytes before the start of a MinimalTuple. As with the previous case,
509 * this can't be told apart from case #1 by inspection; code setting up
510 * or destroying this representation has to know what it's doing.
512 * t_len should always be valid, except in the pointer-to-nothing case.
513 * t_self and t_tableOid should be valid if the HeapTupleData points to
514 * a disk buffer, or if it represents a copy of a tuple on disk. They
515 * should be explicitly set invalid in manufactured tuples.
517 typedef struct HeapTupleData
519 uint32 t_len; /* length of *t_data */
520 ItemPointerData t_self; /* SelfItemPointer */
521 Oid t_tableOid; /* table the tuple came from */
522 HeapTupleHeader t_data; /* -> tuple header and data */
525 typedef HeapTupleData *HeapTuple;
527 #define HEAPTUPLESIZE MAXALIGN(sizeof(HeapTupleData))
530 * GETSTRUCT - given a HeapTuple pointer, return address of the user data
532 #define GETSTRUCT(TUP) ((char *) ((TUP)->t_data) + (TUP)->t_data->t_hoff)
535 * Accessor macros to be used with HeapTuple pointers.
537 #define HeapTupleIsValid(tuple) PointerIsValid(tuple)
539 #define HeapTupleHasNulls(tuple) \
540 (((tuple)->t_data->t_infomask & HEAP_HASNULL) != 0)
542 #define HeapTupleNoNulls(tuple) \
543 (!((tuple)->t_data->t_infomask & HEAP_HASNULL))
545 #define HeapTupleHasVarWidth(tuple) \
546 (((tuple)->t_data->t_infomask & HEAP_HASVARWIDTH) != 0)
548 #define HeapTupleAllFixed(tuple) \
549 (!((tuple)->t_data->t_infomask & HEAP_HASVARWIDTH))
551 #define HeapTupleHasExternal(tuple) \
552 (((tuple)->t_data->t_infomask & HEAP_HASEXTERNAL) != 0)
554 #define HeapTupleIsHotUpdated(tuple) \
555 HeapTupleHeaderIsHotUpdated((tuple)->t_data)
557 #define HeapTupleSetHotUpdated(tuple) \
558 HeapTupleHeaderSetHotUpdated((tuple)->t_data)
560 #define HeapTupleClearHotUpdated(tuple) \
561 HeapTupleHeaderClearHotUpdated((tuple)->t_data)
563 #define HeapTupleIsHeapOnly(tuple) \
564 HeapTupleHeaderIsHeapOnly((tuple)->t_data)
566 #define HeapTupleSetHeapOnly(tuple) \
567 HeapTupleHeaderSetHeapOnly((tuple)->t_data)
569 #define HeapTupleClearHeapOnly(tuple) \
570 HeapTupleHeaderClearHeapOnly((tuple)->t_data)
572 #define HeapTupleGetOid(tuple) \
573 HeapTupleHeaderGetOid((tuple)->t_data)
575 #define HeapTupleSetOid(tuple, oid) \
576 HeapTupleHeaderSetOid((tuple)->t_data, (oid))
580 * WAL record definitions for heapam.c's WAL operations
582 * XLOG allows to store some information in high 4 bits of log
583 * record xl_info field. We use 3 for opcode and one for init bit.
585 #define XLOG_HEAP_INSERT 0x00
586 #define XLOG_HEAP_DELETE 0x10
587 #define XLOG_HEAP_UPDATE 0x20
588 /* 0x030 is free, was XLOG_HEAP_MOVE */
589 #define XLOG_HEAP_HOT_UPDATE 0x40
590 #define XLOG_HEAP_NEWPAGE 0x50
591 #define XLOG_HEAP_LOCK 0x60
592 #define XLOG_HEAP_INPLACE 0x70
594 #define XLOG_HEAP_OPMASK 0x70
596 * When we insert 1st item on new page in INSERT/UPDATE
597 * we can (and we do) restore entire page in redo
599 #define XLOG_HEAP_INIT_PAGE 0x80
601 * We ran out of opcodes, so heapam.c now has a second RmgrId. These opcodes
602 * are associated with RM_HEAP2_ID, but are not logically different from
603 * the ones above associated with RM_HEAP_ID. We apply XLOG_HEAP_OPMASK,
604 * although currently XLOG_HEAP_INIT_PAGE is not used for any of these.
606 #define XLOG_HEAP2_FREEZE 0x00
607 #define XLOG_HEAP2_CLEAN 0x10
608 /* 0x20 is free, was XLOG_HEAP2_CLEAN_MOVE */
609 #define XLOG_HEAP2_CLEANUP_INFO 0x30
610 #define XLOG_HEAP2_VISIBLE 0x40
613 * All what we need to find changed tuple
615 * NB: on most machines, sizeof(xl_heaptid) will include some trailing pad
616 * bytes for alignment. We don't want to store the pad space in the XLOG,
617 * so use SizeOfHeapTid for space calculations. Similar comments apply for
618 * the other xl_FOO structs.
620 typedef struct xl_heaptid
623 ItemPointerData tid; /* changed tuple id */
626 #define SizeOfHeapTid (offsetof(xl_heaptid, tid) + SizeOfIptrData)
628 /* This is what we need to know about delete */
629 typedef struct xl_heap_delete
631 xl_heaptid target; /* deleted tuple id */
632 bool all_visible_cleared; /* PD_ALL_VISIBLE was cleared */
635 #define SizeOfHeapDelete (offsetof(xl_heap_delete, all_visible_cleared) + sizeof(bool))
638 * We don't store the whole fixed part (HeapTupleHeaderData) of an inserted
639 * or updated tuple in WAL; we can save a few bytes by reconstructing the
640 * fields that are available elsewhere in the WAL record, or perhaps just
641 * plain needn't be reconstructed. These are the fields we must store.
642 * NOTE: t_hoff could be recomputed, but we may as well store it because
643 * it will come for free due to alignment considerations.
645 typedef struct xl_heap_header
652 #define SizeOfHeapHeader (offsetof(xl_heap_header, t_hoff) + sizeof(uint8))
654 /* This is what we need to know about insert */
655 typedef struct xl_heap_insert
657 xl_heaptid target; /* inserted tuple id */
658 bool all_visible_cleared; /* PD_ALL_VISIBLE was cleared */
659 /* xl_heap_header & TUPLE DATA FOLLOWS AT END OF STRUCT */
662 #define SizeOfHeapInsert (offsetof(xl_heap_insert, all_visible_cleared) + sizeof(bool))
664 /* This is what we need to know about update|hot_update */
665 typedef struct xl_heap_update
667 xl_heaptid target; /* deleted tuple id */
668 ItemPointerData newtid; /* new inserted tuple id */
669 bool all_visible_cleared; /* PD_ALL_VISIBLE was cleared */
670 bool new_all_visible_cleared; /* same for the page of newtid */
671 /* NEW TUPLE xl_heap_header AND TUPLE DATA FOLLOWS AT END OF STRUCT */
674 #define SizeOfHeapUpdate (offsetof(xl_heap_update, new_all_visible_cleared) + sizeof(bool))
677 * This is what we need to know about vacuum page cleanup/redirect
679 * The array of OffsetNumbers following the fixed part of the record contains:
680 * * for each redirected item: the item offset, then the offset redirected to
681 * * for each now-dead item: the item offset
682 * * for each now-unused item: the item offset
683 * The total number of OffsetNumbers is therefore 2*nredirected+ndead+nunused.
684 * Note that nunused is not explicitly stored, but may be found by reference
685 * to the total record length.
687 typedef struct xl_heap_clean
691 TransactionId latestRemovedXid;
694 /* OFFSET NUMBERS FOLLOW */
697 #define SizeOfHeapClean (offsetof(xl_heap_clean, ndead) + sizeof(uint16))
700 * Cleanup_info is required in some cases during a lazy VACUUM.
701 * Used for reporting the results of HeapTupleHeaderAdvanceLatestRemovedXid()
702 * see vacuumlazy.c for full explanation
704 typedef struct xl_heap_cleanup_info
707 TransactionId latestRemovedXid;
708 } xl_heap_cleanup_info;
710 #define SizeOfHeapCleanupInfo (sizeof(xl_heap_cleanup_info))
712 /* This is for replacing a page's contents in toto */
713 /* NB: this is used for indexes as well as heaps */
714 typedef struct xl_heap_newpage
718 BlockNumber blkno; /* location of new page */
719 /* entire page contents follow at end of record */
722 #define SizeOfHeapNewpage (offsetof(xl_heap_newpage, blkno) + sizeof(BlockNumber))
724 /* This is what we need to know about lock */
725 typedef struct xl_heap_lock
727 xl_heaptid target; /* locked tuple id */
728 TransactionId locking_xid; /* might be a MultiXactId not xid */
729 bool xid_is_mxact; /* is it? */
730 bool shared_lock; /* shared or exclusive row lock? */
733 #define SizeOfHeapLock (offsetof(xl_heap_lock, shared_lock) + sizeof(bool))
735 /* This is what we need to know about in-place update */
736 typedef struct xl_heap_inplace
738 xl_heaptid target; /* updated tuple id */
739 /* TUPLE DATA FOLLOWS AT END OF STRUCT */
742 #define SizeOfHeapInplace (offsetof(xl_heap_inplace, target) + SizeOfHeapTid)
744 /* This is what we need to know about tuple freezing during vacuum */
745 typedef struct xl_heap_freeze
749 TransactionId cutoff_xid;
750 /* TUPLE OFFSET NUMBERS FOLLOW AT THE END */
753 #define SizeOfHeapFreeze (offsetof(xl_heap_freeze, cutoff_xid) + sizeof(TransactionId))
755 /* This is what we need to know about setting a visibility map bit */
756 typedef struct xl_heap_visible
762 #define SizeOfHeapVisible (offsetof(xl_heap_visible, block) + sizeof(BlockNumber))
764 extern void HeapTupleHeaderAdvanceLatestRemovedXid(HeapTupleHeader tuple,
765 TransactionId *latestRemovedXid);
767 /* HeapTupleHeader functions implemented in utils/time/combocid.c */
768 extern CommandId HeapTupleHeaderGetCmin(HeapTupleHeader tup);
769 extern CommandId HeapTupleHeaderGetCmax(HeapTupleHeader tup);
770 extern void HeapTupleHeaderAdjustCmax(HeapTupleHeader tup,
777 * Fetch a user attribute's value as a Datum (might be either a
778 * value, or a pointer into the data area of the tuple).
780 * This must not be used when a system attribute might be requested.
781 * Furthermore, the passed attnum MUST be valid. Use heap_getattr()
782 * instead, if in doubt.
784 * This gets called many times, so we macro the cacheable and NULL
785 * lookups, and call nocachegetattr() for the rest.
789 #if !defined(DISABLE_COMPLEX_MACRO)
791 #define fastgetattr(tup, attnum, tupleDesc, isnull) \
793 AssertMacro((attnum) > 0), \
794 (*(isnull) = false), \
795 HeapTupleNoNulls(tup) ? \
797 (tupleDesc)->attrs[(attnum)-1]->attcacheoff >= 0 ? \
799 fetchatt((tupleDesc)->attrs[(attnum)-1], \
800 (char *) (tup)->t_data + (tup)->t_data->t_hoff + \
801 (tupleDesc)->attrs[(attnum)-1]->attcacheoff) \
804 nocachegetattr((tup), (attnum), (tupleDesc)) \
808 att_isnull((attnum)-1, (tup)->t_data->t_bits) ? \
810 (*(isnull) = true), \
815 nocachegetattr((tup), (attnum), (tupleDesc)) \
819 #else /* defined(DISABLE_COMPLEX_MACRO) */
821 extern Datum fastgetattr(HeapTuple tup, int attnum, TupleDesc tupleDesc,
823 #endif /* defined(DISABLE_COMPLEX_MACRO) */
829 * Extract an attribute of a heap tuple and return it as a Datum.
830 * This works for either system or user attributes. The given attnum
831 * is properly range-checked.
833 * If the field in question has a NULL value, we return a zero Datum
834 * and set *isnull == true. Otherwise, we set *isnull == false.
836 * <tup> is the pointer to the heap tuple. <attnum> is the attribute
837 * number of the column (field) caller wants. <tupleDesc> is a
838 * pointer to the structure describing the row and all its fields.
841 #define heap_getattr(tup, attnum, tupleDesc, isnull) \
843 AssertMacro((tup) != NULL), \
847 ((attnum) > (int) HeapTupleHeaderGetNatts((tup)->t_data)) ? \
849 (*(isnull) = true), \
853 fastgetattr((tup), (attnum), (tupleDesc), (isnull)) \
856 heap_getsysattr((tup), (attnum), (tupleDesc), (isnull)) \
860 /* prototypes for functions in common/heaptuple.c */
861 extern Size heap_compute_data_size(TupleDesc tupleDesc,
862 Datum *values, bool *isnull);
863 extern void heap_fill_tuple(TupleDesc tupleDesc,
864 Datum *values, bool *isnull,
865 char *data, Size data_size,
866 uint16 *infomask, bits8 *bit);
867 extern bool heap_attisnull(HeapTuple tup, int attnum);
868 extern Datum nocachegetattr(HeapTuple tup, int attnum,
870 extern Datum heap_getsysattr(HeapTuple tup, int attnum, TupleDesc tupleDesc,
872 extern HeapTuple heap_copytuple(HeapTuple tuple);
873 extern void heap_copytuple_with_tuple(HeapTuple src, HeapTuple dest);
874 extern HeapTuple heap_form_tuple(TupleDesc tupleDescriptor,
875 Datum *values, bool *isnull);
876 extern HeapTuple heap_modify_tuple(HeapTuple tuple,
881 extern void heap_deform_tuple(HeapTuple tuple, TupleDesc tupleDesc,
882 Datum *values, bool *isnull);
884 /* these three are deprecated versions of the three above: */
885 extern HeapTuple heap_formtuple(TupleDesc tupleDescriptor,
886 Datum *values, char *nulls);
887 extern HeapTuple heap_modifytuple(HeapTuple tuple,
892 extern void heap_deformtuple(HeapTuple tuple, TupleDesc tupleDesc,
893 Datum *values, char *nulls);
894 extern void heap_freetuple(HeapTuple htup);
895 extern MinimalTuple heap_form_minimal_tuple(TupleDesc tupleDescriptor,
896 Datum *values, bool *isnull);
897 extern void heap_free_minimal_tuple(MinimalTuple mtup);
898 extern MinimalTuple heap_copy_minimal_tuple(MinimalTuple mtup);
899 extern HeapTuple heap_tuple_from_minimal_tuple(MinimalTuple mtup);
900 extern MinimalTuple minimal_tuple_from_heap_tuple(HeapTuple htup);