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/*-------------------------------------------------------------------------
*
* htup.h
* POSTGRES heap tuple definitions.
*
*
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/htup.h,v 1.98 2008/01/01 19:45:56 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef HTUP_H
#define HTUP_H
#include "storage/itemptr.h"
#include "storage/relfilenode.h"
/*
* MaxTupleAttributeNumber limits the number of (user) columns in a tuple.
* The key limit on this value is that the size of the fixed overhead for
* a tuple, plus the size of the null-values bitmap (at 1 bit per column),
* plus MAXALIGN alignment, must fit into t_hoff which is uint8. On most
* machines the upper limit without making t_hoff wider would be a little
* over 1700. We use round numbers here and for MaxHeapAttributeNumber
* so that alterations in HeapTupleHeaderData layout won't change the
* supported max number of columns.
*/
#define MaxTupleAttributeNumber 1664 /* 8 * 208 */
/*
* MaxHeapAttributeNumber limits the number of (user) columns in a table.
* This should be somewhat less than MaxTupleAttributeNumber. It must be
* at least one less, else we will fail to do UPDATEs on a maximal-width
* table (because UPDATE has to form working tuples that include CTID).
* In practice we want some additional daylight so that we can gracefully
* support operations that add hidden "resjunk" columns, for example
* SELECT * FROM wide_table ORDER BY foo, bar, baz.
* In any case, depending on column data types you will likely be running
* into the disk-block-based limit on overall tuple size if you have more
* than a thousand or so columns. TOAST won't help.
*/
#define MaxHeapAttributeNumber 1600 /* 8 * 200 */
/*
* Heap tuple header. To avoid wasting space, the fields should be
* laid out in such a way as to avoid structure padding.
*
* Datums of composite types (row types) share the same general structure
* as on-disk tuples, so that the same routines can be used to build and
* examine them. However the requirements are slightly different: a Datum
* does not need any transaction visibility information, and it does need
* a length word and some embedded type information. We can achieve this
* by overlaying the xmin/cmin/xmax/cmax/xvac fields of a heap tuple
* with the fields needed in the Datum case. Typically, all tuples built
* in-memory will be initialized with the Datum fields; but when a tuple is
* about to be inserted in a table, the transaction fields will be filled,
* overwriting the datum fields.
*
* The overall structure of a heap tuple looks like:
* fixed fields (HeapTupleHeaderData struct)
* nulls bitmap (if HEAP_HASNULL is set in t_infomask)
* alignment padding (as needed to make user data MAXALIGN'd)
* object ID (if HEAP_HASOID is set in t_infomask)
* user data fields
*
* We store five "virtual" fields Xmin, Cmin, Xmax, Cmax, and Xvac in three
* physical fields. Xmin and Xmax are always really stored, but Cmin, Cmax
* and Xvac share a field. This works because we know that Cmin and Cmax
* are only interesting for the lifetime of the inserting and deleting
* transaction respectively. If a tuple is inserted and deleted in the same
* transaction, we store a "combo" command id that can be mapped to the real
* cmin and cmax, but only by use of local state within the originating
* backend. See combocid.c for more details. Meanwhile, Xvac is only set
* by VACUUM FULL, which does not have any command sub-structure and so does
* not need either Cmin or Cmax. (This requires that VACUUM FULL never try
* to move a tuple whose Cmin or Cmax is still interesting, ie, an insert-
* in-progress or delete-in-progress tuple.)
*
* A word about t_ctid: whenever a new tuple is stored on disk, its t_ctid
* is initialized with its own TID (location). If the tuple is ever updated,
* its t_ctid is changed to point to the replacement version of the tuple.
* Thus, a tuple is the latest version of its row iff XMAX is invalid or
* t_ctid points to itself (in which case, if XMAX is valid, the tuple is
* either locked or deleted). One can follow the chain of t_ctid links
* to find the newest version of the row. Beware however that VACUUM might
* erase the pointed-to (newer) tuple before erasing the pointing (older)
* tuple. Hence, when following a t_ctid link, it is necessary to check
* to see if the referenced slot is empty or contains an unrelated tuple.
* Check that the referenced tuple has XMIN equal to the referencing tuple's
* XMAX to verify that it is actually the descendant version and not an
* unrelated tuple stored into a slot recently freed by VACUUM. If either
* check fails, one may assume that there is no live descendant version.
*
* Following the fixed header fields, the nulls bitmap is stored (beginning
* at t_bits). The bitmap is *not* stored if t_infomask shows that there
* are no nulls in the tuple. If an OID field is present (as indicated by
* t_infomask), then it is stored just before the user data, which begins at
* the offset shown by t_hoff. Note that t_hoff must be a multiple of
* MAXALIGN.
*/
typedef struct HeapTupleFields
{
TransactionId t_xmin; /* inserting xact ID */
TransactionId t_xmax; /* deleting or locking xact ID */
union
{
CommandId t_cid; /* inserting or deleting command ID, or both */
TransactionId t_xvac; /* VACUUM FULL xact ID */
} t_field3;
} HeapTupleFields;
typedef struct DatumTupleFields
{
int32 datum_len_; /* varlena header (do not touch directly!) */
int32 datum_typmod; /* -1, or identifier of a record type */
Oid datum_typeid; /* composite type OID, or RECORDOID */
/*
* Note: field ordering is chosen with thought that Oid might someday
* widen to 64 bits.
*/
} DatumTupleFields;
typedef struct HeapTupleHeaderData
{
union
{
HeapTupleFields t_heap;
DatumTupleFields t_datum;
} t_choice;
ItemPointerData t_ctid; /* current TID of this or newer tuple */
/* Fields below here must match MinimalTupleData! */
uint16 t_infomask2; /* number of attributes + various flags */
uint16 t_infomask; /* various flag bits, see below */
uint8 t_hoff; /* sizeof header incl. bitmap, padding */
/* ^ - 23 bytes - ^ */
bits8 t_bits[1]; /* bitmap of NULLs -- VARIABLE LENGTH */
/* MORE DATA FOLLOWS AT END OF STRUCT */
} HeapTupleHeaderData;
typedef HeapTupleHeaderData *HeapTupleHeader;
/*
* information stored in t_infomask:
*/
#define HEAP_HASNULL 0x0001 /* has null attribute(s) */
#define HEAP_HASVARWIDTH 0x0002 /* has variable-width attribute(s) */
#define HEAP_HASEXTERNAL 0x0004 /* has external stored attribute(s) */
#define HEAP_HASOID 0x0008 /* has an object-id field */
/* bit 0x0010 is available */
#define HEAP_COMBOCID 0x0020 /* t_cid is a combo cid */
#define HEAP_XMAX_EXCL_LOCK 0x0040 /* xmax is exclusive locker */
#define HEAP_XMAX_SHARED_LOCK 0x0080 /* xmax is shared locker */
/* if either LOCK bit is set, xmax hasn't deleted the tuple, only locked it */
#define HEAP_IS_LOCKED (HEAP_XMAX_EXCL_LOCK | HEAP_XMAX_SHARED_LOCK)
#define HEAP_XMIN_COMMITTED 0x0100 /* t_xmin committed */
#define HEAP_XMIN_INVALID 0x0200 /* t_xmin invalid/aborted */
#define HEAP_XMAX_COMMITTED 0x0400 /* t_xmax committed */
#define HEAP_XMAX_INVALID 0x0800 /* t_xmax invalid/aborted */
#define HEAP_XMAX_IS_MULTI 0x1000 /* t_xmax is a MultiXactId */
#define HEAP_UPDATED 0x2000 /* this is UPDATEd version of row */
#define HEAP_MOVED_OFF 0x4000 /* moved to another place by VACUUM
* FULL */
#define HEAP_MOVED_IN 0x8000 /* moved from another place by VACUUM
* FULL */
#define HEAP_MOVED (HEAP_MOVED_OFF | HEAP_MOVED_IN)
#define HEAP_XACT_MASK 0xFFE0 /* visibility-related bits */
/*
* information stored in t_infomask2:
*/
#define HEAP_NATTS_MASK 0x07FF /* 11 bits for number of attributes */
/* bits 0x3800 are available */
#define HEAP_HOT_UPDATED 0x4000 /* tuple was HOT-updated */
#define HEAP_ONLY_TUPLE 0x8000 /* this is heap-only tuple */
#define HEAP2_XACT_MASK 0xC000 /* visibility-related bits */
/*
* HeapTupleHeader accessor macros
*
* Note: beware of multiple evaluations of "tup" argument. But the Set
* macros evaluate their other argument only once.
*/
#define HeapTupleHeaderGetXmin(tup) \
( \
(tup)->t_choice.t_heap.t_xmin \
)
#define HeapTupleHeaderSetXmin(tup, xid) \
( \
(tup)->t_choice.t_heap.t_xmin = (xid) \
)
#define HeapTupleHeaderGetXmax(tup) \
( \
(tup)->t_choice.t_heap.t_xmax \
)
#define HeapTupleHeaderSetXmax(tup, xid) \
( \
(tup)->t_choice.t_heap.t_xmax = (xid) \
)
/*
* HeapTupleHeaderGetRawCommandId will give you what's in the header whether
* it is useful or not. Most code should use HeapTupleHeaderGetCmin or
* HeapTupleHeaderGetCmax instead, but note that those Assert that you can
* get a legitimate result, ie you are in the originating transaction!
*/
#define HeapTupleHeaderGetRawCommandId(tup) \
( \
(tup)->t_choice.t_heap.t_field3.t_cid \
)
/* SetCmin is reasonably simple since we never need a combo CID */
#define HeapTupleHeaderSetCmin(tup, cid) \
do { \
Assert(!((tup)->t_infomask & HEAP_MOVED)); \
(tup)->t_choice.t_heap.t_field3.t_cid = (cid); \
(tup)->t_infomask &= ~HEAP_COMBOCID; \
} while (0)
/* SetCmax must be used after HeapTupleHeaderAdjustCmax; see combocid.c */
#define HeapTupleHeaderSetCmax(tup, cid, iscombo) \
do { \
Assert(!((tup)->t_infomask & HEAP_MOVED)); \
(tup)->t_choice.t_heap.t_field3.t_cid = (cid); \
if (iscombo) \
(tup)->t_infomask |= HEAP_COMBOCID; \
else \
(tup)->t_infomask &= ~HEAP_COMBOCID; \
} while (0)
#define HeapTupleHeaderGetXvac(tup) \
( \
((tup)->t_infomask & HEAP_MOVED) ? \
(tup)->t_choice.t_heap.t_field3.t_xvac \
: \
InvalidTransactionId \
)
#define HeapTupleHeaderSetXvac(tup, xid) \
do { \
Assert((tup)->t_infomask & HEAP_MOVED); \
(tup)->t_choice.t_heap.t_field3.t_xvac = (xid); \
} while (0)
#define HeapTupleHeaderGetDatumLength(tup) \
VARSIZE(tup)
#define HeapTupleHeaderSetDatumLength(tup, len) \
SET_VARSIZE(tup, len)
#define HeapTupleHeaderGetTypeId(tup) \
( \
(tup)->t_choice.t_datum.datum_typeid \
)
#define HeapTupleHeaderSetTypeId(tup, typeid) \
( \
(tup)->t_choice.t_datum.datum_typeid = (typeid) \
)
#define HeapTupleHeaderGetTypMod(tup) \
( \
(tup)->t_choice.t_datum.datum_typmod \
)
#define HeapTupleHeaderSetTypMod(tup, typmod) \
( \
(tup)->t_choice.t_datum.datum_typmod = (typmod) \
)
#define HeapTupleHeaderGetOid(tup) \
( \
((tup)->t_infomask & HEAP_HASOID) ? \
*((Oid *) ((char *)(tup) + (tup)->t_hoff - sizeof(Oid))) \
: \
InvalidOid \
)
#define HeapTupleHeaderSetOid(tup, oid) \
do { \
Assert((tup)->t_infomask & HEAP_HASOID); \
*((Oid *) ((char *)(tup) + (tup)->t_hoff - sizeof(Oid))) = (oid); \
} while (0)
/*
* Note that we stop considering a tuple HOT-updated as soon as it is known
* aborted or the would-be updating transaction is known aborted. For best
* efficiency, check tuple visibility before using this macro, so that the
* INVALID bits will be as up to date as possible.
*/
#define HeapTupleHeaderIsHotUpdated(tup) \
( \
((tup)->t_infomask2 & HEAP_HOT_UPDATED) != 0 && \
((tup)->t_infomask & (HEAP_XMIN_INVALID | HEAP_XMAX_INVALID)) == 0 \
)
#define HeapTupleHeaderSetHotUpdated(tup) \
( \
(tup)->t_infomask2 |= HEAP_HOT_UPDATED \
)
#define HeapTupleHeaderClearHotUpdated(tup) \
( \
(tup)->t_infomask2 &= ~HEAP_HOT_UPDATED \
)
#define HeapTupleHeaderIsHeapOnly(tup) \
( \
(tup)->t_infomask2 & HEAP_ONLY_TUPLE \
)
#define HeapTupleHeaderSetHeapOnly(tup) \
( \
(tup)->t_infomask2 |= HEAP_ONLY_TUPLE \
)
#define HeapTupleHeaderClearHeapOnly(tup) \
( \
(tup)->t_infomask2 &= ~HEAP_ONLY_TUPLE \
)
#define HeapTupleHeaderGetNatts(tup) \
((tup)->t_infomask2 & HEAP_NATTS_MASK)
#define HeapTupleHeaderSetNatts(tup, natts) \
( \
(tup)->t_infomask2 = ((tup)->t_infomask2 & ~HEAP_NATTS_MASK) | (natts) \
)
/*
* BITMAPLEN(NATTS) -
* Computes size of null bitmap given number of data columns.
*/
#define BITMAPLEN(NATTS) (((int)(NATTS) + 7) / 8)
/*
* MaxHeapTupleSize is the maximum allowed size of a heap tuple, including
* header and MAXALIGN alignment padding. Basically it's BLCKSZ minus the
* other stuff that has to be on a disk page. Since heap pages use no
* "special space", there's no deduction for that.
*
* NOTE: we do not need to count an ItemId for the tuple because
* sizeof(PageHeaderData) includes the first ItemId on the page. But beware
* of assuming that, say, you can fit 2 tuples of size MaxHeapTupleSize/2
* on the same page.
*/
#define MaxHeapTupleSize (BLCKSZ - MAXALIGN(sizeof(PageHeaderData)))
/*
* MaxHeapTuplesPerPage is an upper bound on the number of tuples that can
* fit on one heap page. (Note that indexes could have more, because they
* use a smaller tuple header.) We arrive at the divisor because each tuple
* must be maxaligned, and it must have an associated item pointer.
*
* Note: with HOT, there could theoretically be more line pointers (not actual
* tuples) than this on a heap page. However we constrain the number of line
* pointers to this anyway, to avoid excessive line-pointer bloat and not
* require increases in the size of work arrays.
*/
#define MaxHeapTuplesPerPage \
((int) ((BLCKSZ - offsetof(PageHeaderData, pd_linp)) / \
(MAXALIGN(offsetof(HeapTupleHeaderData, t_bits)) + sizeof(ItemIdData))))
/*
* MaxAttrSize is a somewhat arbitrary upper limit on the declared size of
* data fields of char(n) and similar types. It need not have anything
* directly to do with the *actual* upper limit of varlena values, which
* is currently 1Gb (see TOAST structures in postgres.h). I've set it
* at 10Mb which seems like a reasonable number --- tgl 8/6/00.
*/
#define MaxAttrSize (10 * 1024 * 1024)
/*
* Attribute numbers for the system-defined attributes
*/
#define SelfItemPointerAttributeNumber (-1)
#define ObjectIdAttributeNumber (-2)
#define MinTransactionIdAttributeNumber (-3)
#define MinCommandIdAttributeNumber (-4)
#define MaxTransactionIdAttributeNumber (-5)
#define MaxCommandIdAttributeNumber (-6)
#define TableOidAttributeNumber (-7)
#define FirstLowInvalidHeapAttributeNumber (-8)
/*
* MinimalTuple is an alternative representation that is used for transient
* tuples inside the executor, in places where transaction status information
* is not required, the tuple rowtype is known, and shaving off a few bytes
* is worthwhile because we need to store many tuples. The representation
* is chosen so that tuple access routines can work with either full or
* minimal tuples via a HeapTupleData pointer structure. The access routines
* see no difference, except that they must not access the transaction status
* or t_ctid fields because those aren't there.
*
* For the most part, MinimalTuples should be accessed via TupleTableSlot
* routines. These routines will prevent access to the "system columns"
* and thereby prevent accidental use of the nonexistent fields.
*
* MinimalTupleData contains a length word, some padding, and fields matching
* HeapTupleHeaderData beginning with t_infomask2. The padding is chosen so
* that offsetof(t_infomask2) is the same modulo MAXIMUM_ALIGNOF in both
* structs. This makes data alignment rules equivalent in both cases.
*
* When a minimal tuple is accessed via a HeapTupleData pointer, t_data is
* set to point MINIMAL_TUPLE_OFFSET bytes before the actual start of the
* minimal tuple --- that is, where a full tuple matching the minimal tuple's
* data would start. This trick is what makes the structs seem equivalent.
*
* Note that t_hoff is computed the same as in a full tuple, hence it includes
* the MINIMAL_TUPLE_OFFSET distance. t_len does not include that, however.
*/
#define MINIMAL_TUPLE_OFFSET \
((offsetof(HeapTupleHeaderData, t_infomask2) - sizeof(uint32)) / MAXIMUM_ALIGNOF * MAXIMUM_ALIGNOF)
#define MINIMAL_TUPLE_PADDING \
((offsetof(HeapTupleHeaderData, t_infomask2) - sizeof(uint32)) % MAXIMUM_ALIGNOF)
typedef struct MinimalTupleData
{
uint32 t_len; /* actual length of minimal tuple */
char mt_padding[MINIMAL_TUPLE_PADDING];
/* Fields below here must match HeapTupleHeaderData! */
uint16 t_infomask2; /* number of attributes + various flags */
uint16 t_infomask; /* various flag bits, see below */
uint8 t_hoff; /* sizeof header incl. bitmap, padding */
/* ^ - 23 bytes - ^ */
bits8 t_bits[1]; /* bitmap of NULLs -- VARIABLE LENGTH */
/* MORE DATA FOLLOWS AT END OF STRUCT */
} MinimalTupleData;
typedef MinimalTupleData *MinimalTuple;
/*
* HeapTupleData is an in-memory data structure that points to a tuple.
*
* There are several ways in which this data structure is used:
*
* * Pointer to a tuple in a disk buffer: t_data points directly into the
* buffer (which the code had better be holding a pin on, but this is not
* reflected in HeapTupleData itself).
*
* * Pointer to nothing: t_data is NULL. This is used as a failure indication
* in some functions.
*
* * Part of a palloc'd tuple: the HeapTupleData itself and the tuple
* form a single palloc'd chunk. t_data points to the memory location
* immediately following the HeapTupleData struct (at offset HEAPTUPLESIZE).
* This is the output format of heap_form_tuple and related routines.
*
* * Separately allocated tuple: t_data points to a palloc'd chunk that
* is not adjacent to the HeapTupleData. (This case is deprecated since
* it's difficult to tell apart from case #1. It should be used only in
* limited contexts where the code knows that case #1 will never apply.)
*
* * Separately allocated minimal tuple: t_data points MINIMAL_TUPLE_OFFSET
* bytes before the start of a MinimalTuple. As with the previous case,
* this can't be told apart from case #1 by inspection; code setting up
* or destroying this representation has to know what it's doing.
*
* t_len should always be valid, except in the pointer-to-nothing case.
* t_self and t_tableOid should be valid if the HeapTupleData points to
* a disk buffer, or if it represents a copy of a tuple on disk. They
* should be explicitly set invalid in manufactured tuples.
*/
typedef struct HeapTupleData
{
uint32 t_len; /* length of *t_data */
ItemPointerData t_self; /* SelfItemPointer */
Oid t_tableOid; /* table the tuple came from */
HeapTupleHeader t_data; /* -> tuple header and data */
} HeapTupleData;
typedef HeapTupleData *HeapTuple;
#define HEAPTUPLESIZE MAXALIGN(sizeof(HeapTupleData))
/*
* GETSTRUCT - given a HeapTuple pointer, return address of the user data
*/
#define GETSTRUCT(TUP) ((char *) ((TUP)->t_data) + (TUP)->t_data->t_hoff)
/*
* Accessor macros to be used with HeapTuple pointers.
*/
#define HeapTupleIsValid(tuple) PointerIsValid(tuple)
#define HeapTupleHasNulls(tuple) \
(((tuple)->t_data->t_infomask & HEAP_HASNULL) != 0)
#define HeapTupleNoNulls(tuple) \
(!((tuple)->t_data->t_infomask & HEAP_HASNULL))
#define HeapTupleHasVarWidth(tuple) \
(((tuple)->t_data->t_infomask & HEAP_HASVARWIDTH) != 0)
#define HeapTupleAllFixed(tuple) \
(!((tuple)->t_data->t_infomask & HEAP_HASVARWIDTH))
#define HeapTupleHasExternal(tuple) \
(((tuple)->t_data->t_infomask & HEAP_HASEXTERNAL) != 0)
#define HeapTupleIsHotUpdated(tuple) \
HeapTupleHeaderIsHotUpdated((tuple)->t_data)
#define HeapTupleSetHotUpdated(tuple) \
HeapTupleHeaderSetHotUpdated((tuple)->t_data)
#define HeapTupleClearHotUpdated(tuple) \
HeapTupleHeaderClearHotUpdated((tuple)->t_data)
#define HeapTupleIsHeapOnly(tuple) \
HeapTupleHeaderIsHeapOnly((tuple)->t_data)
#define HeapTupleSetHeapOnly(tuple) \
HeapTupleHeaderSetHeapOnly((tuple)->t_data)
#define HeapTupleClearHeapOnly(tuple) \
HeapTupleHeaderClearHeapOnly((tuple)->t_data)
#define HeapTupleGetOid(tuple) \
HeapTupleHeaderGetOid((tuple)->t_data)
#define HeapTupleSetOid(tuple, oid) \
HeapTupleHeaderSetOid((tuple)->t_data, (oid))
/*
* WAL record definitions for heapam.c's WAL operations
*
* XLOG allows to store some information in high 4 bits of log
* record xl_info field. We use 3 for opcode and one for init bit.
*/
#define XLOG_HEAP_INSERT 0x00
#define XLOG_HEAP_DELETE 0x10
#define XLOG_HEAP_UPDATE 0x20
#define XLOG_HEAP_MOVE 0x30
#define XLOG_HEAP_HOT_UPDATE 0x40
#define XLOG_HEAP_NEWPAGE 0x50
#define XLOG_HEAP_LOCK 0x60
#define XLOG_HEAP_INPLACE 0x70
#define XLOG_HEAP_OPMASK 0x70
/*
* When we insert 1st item on new page in INSERT/UPDATE
* we can (and we do) restore entire page in redo
*/
#define XLOG_HEAP_INIT_PAGE 0x80
/*
* We ran out of opcodes, so heapam.c now has a second RmgrId. These opcodes
* are associated with RM_HEAP2_ID, but are not logically different from
* the ones above associated with RM_HEAP_ID. We apply XLOG_HEAP_OPMASK,
* although currently XLOG_HEAP_INIT_PAGE is not used for any of these.
*/
#define XLOG_HEAP2_FREEZE 0x00
#define XLOG_HEAP2_CLEAN 0x10
#define XLOG_HEAP2_CLEAN_MOVE 0x20
/*
* All what we need to find changed tuple
*
* NB: on most machines, sizeof(xl_heaptid) will include some trailing pad
* bytes for alignment. We don't want to store the pad space in the XLOG,
* so use SizeOfHeapTid for space calculations. Similar comments apply for
* the other xl_FOO structs.
*/
typedef struct xl_heaptid
{
RelFileNode node;
ItemPointerData tid; /* changed tuple id */
} xl_heaptid;
#define SizeOfHeapTid (offsetof(xl_heaptid, tid) + SizeOfIptrData)
/* This is what we need to know about delete */
typedef struct xl_heap_delete
{
xl_heaptid target; /* deleted tuple id */
} xl_heap_delete;
#define SizeOfHeapDelete (offsetof(xl_heap_delete, target) + SizeOfHeapTid)
/*
* We don't store the whole fixed part (HeapTupleHeaderData) of an inserted
* or updated tuple in WAL; we can save a few bytes by reconstructing the
* fields that are available elsewhere in the WAL record, or perhaps just
* plain needn't be reconstructed. These are the fields we must store.
* NOTE: t_hoff could be recomputed, but we may as well store it because
* it will come for free due to alignment considerations.
*/
typedef struct xl_heap_header
{
uint16 t_infomask2;
uint16 t_infomask;
uint8 t_hoff;
} xl_heap_header;
#define SizeOfHeapHeader (offsetof(xl_heap_header, t_hoff) + sizeof(uint8))
/* This is what we need to know about insert */
typedef struct xl_heap_insert
{
xl_heaptid target; /* inserted tuple id */
/* xl_heap_header & TUPLE DATA FOLLOWS AT END OF STRUCT */
} xl_heap_insert;
#define SizeOfHeapInsert (offsetof(xl_heap_insert, target) + SizeOfHeapTid)
/* This is what we need to know about update|move|hot_update */
typedef struct xl_heap_update
{
xl_heaptid target; /* deleted tuple id */
ItemPointerData newtid; /* new inserted tuple id */
/* NEW TUPLE xl_heap_header (PLUS xmax & xmin IF MOVE OP) */
/* and TUPLE DATA FOLLOWS AT END OF STRUCT */
} xl_heap_update;
#define SizeOfHeapUpdate (offsetof(xl_heap_update, newtid) + SizeOfIptrData)
/*
* This is what we need to know about vacuum page cleanup/redirect
*
* The array of OffsetNumbers following the fixed part of the record contains:
* * for each redirected item: the item offset, then the offset redirected to
* * for each now-dead item: the item offset
* * for each now-unused item: the item offset
* The total number of OffsetNumbers is therefore 2*nredirected+ndead+nunused.
* Note that nunused is not explicitly stored, but may be found by reference
* to the total record length.
*
* If the opcode is CLEAN_MOVE instead of CLEAN, then each redirection pair
* should be interpreted as physically moving the "to" item pointer to the
* "from" slot, rather than placing a redirection item in the "from" slot.
* The moved pointers should be replaced by LP_UNUSED items (there will not
* be explicit entries in the "now-unused" list for this). Also, the
* HEAP_ONLY bit in the moved tuples must be turned off.
*/
typedef struct xl_heap_clean
{
RelFileNode node;
BlockNumber block;
uint16 nredirected;
uint16 ndead;
/* OFFSET NUMBERS FOLLOW */
} xl_heap_clean;
#define SizeOfHeapClean (offsetof(xl_heap_clean, ndead) + sizeof(uint16))
/* This is for replacing a page's contents in toto */
/* NB: this is used for indexes as well as heaps */
typedef struct xl_heap_newpage
{
RelFileNode node;
BlockNumber blkno; /* location of new page */
/* entire page contents follow at end of record */
} xl_heap_newpage;
#define SizeOfHeapNewpage (offsetof(xl_heap_newpage, blkno) + sizeof(BlockNumber))
/* This is what we need to know about lock */
typedef struct xl_heap_lock
{
xl_heaptid target; /* locked tuple id */
TransactionId locking_xid; /* might be a MultiXactId not xid */
bool xid_is_mxact; /* is it? */
bool shared_lock; /* shared or exclusive row lock? */
} xl_heap_lock;
#define SizeOfHeapLock (offsetof(xl_heap_lock, shared_lock) + sizeof(bool))
/* This is what we need to know about in-place update */
typedef struct xl_heap_inplace
{
xl_heaptid target; /* updated tuple id */
/* TUPLE DATA FOLLOWS AT END OF STRUCT */
} xl_heap_inplace;
#define SizeOfHeapInplace (offsetof(xl_heap_inplace, target) + SizeOfHeapTid)
/* This is what we need to know about tuple freezing during vacuum */
typedef struct xl_heap_freeze
{
RelFileNode node;
BlockNumber block;
TransactionId cutoff_xid;
/* TUPLE OFFSET NUMBERS FOLLOW AT THE END */
} xl_heap_freeze;
#define SizeOfHeapFreeze (offsetof(xl_heap_freeze, cutoff_xid) + sizeof(TransactionId))
/* HeapTupleHeader functions implemented in utils/time/combocid.c */
extern CommandId HeapTupleHeaderGetCmin(HeapTupleHeader tup);
extern CommandId HeapTupleHeaderGetCmax(HeapTupleHeader tup);
extern void HeapTupleHeaderAdjustCmax(HeapTupleHeader tup,
CommandId *cmax,
bool *iscombo);
#endif /* HTUP_H */