| /*------------------------------------------------------------------------- |
| * |
| * htup_details.h |
| * POSTGRES heap tuple header definitions. |
| * |
| * |
| * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group |
| * Portions Copyright (c) 1994, Regents of the University of California |
| * |
| * src/include/access/htup_details.h |
| * |
| *------------------------------------------------------------------------- |
| */ |
| #ifndef HTUP_DETAILS_H |
| #define HTUP_DETAILS_H |
| |
| #include "access/htup.h" |
| #include "access/transam.h" |
| #include "access/tupdesc.h" |
| #include "access/tupmacs.h" |
| #include "storage/bufpage.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_OLD is set in t_infomask, not created |
| * anymore) |
| * 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 |
| * old-style VACUUM FULL, which does not have any command sub-structure and so |
| * does not need either Cmin or Cmax. (This requires that old-style 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. Or |
| * if the tuple is moved from one partition to another, due to an update of |
| * the partition key, t_ctid is set to a special value to indicate that |
| * (see ItemPointerSetMovedPartitions). 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, unless it was moved to a different |
| * partition. 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. |
| * |
| * t_ctid is sometimes used to store a speculative insertion token, instead |
| * of a real TID. A speculative token is set on a tuple that's being |
| * inserted, until the inserter is sure that it wants to go ahead with the |
| * insertion. Hence a token should only be seen on a tuple with an XMAX |
| * that's still in-progress, or invalid/aborted. The token is replaced with |
| * the tuple's real TID when the insertion is confirmed. One should never |
| * see a speculative insertion token while following a chain of t_ctid links, |
| * because they are not used on updates, only insertions. |
| * |
| * 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; /* old-style 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 */ |
| |
| /* |
| * datum_typeid cannot be a domain over composite, only plain composite, |
| * even if the datum is meant as a value of a domain-over-composite type. |
| * This is in line with the general principle that CoerceToDomain does not |
| * change the physical representation of the base type value. |
| * |
| * Note: field ordering is chosen with thought that Oid might someday |
| * widen to 64 bits. |
| */ |
| } DatumTupleFields; |
| |
| struct HeapTupleHeaderData |
| { |
| union |
| { |
| HeapTupleFields t_heap; |
| DatumTupleFields t_datum; |
| } t_choice; |
| |
| ItemPointerData t_ctid; /* current TID of this or newer tuple (or a |
| * speculative insertion token) */ |
| |
| /* Fields below here must match MinimalTupleData! */ |
| |
| #define FIELDNO_HEAPTUPLEHEADERDATA_INFOMASK2 2 |
| uint16 t_infomask2; /* number of attributes + various flags */ |
| |
| #define FIELDNO_HEAPTUPLEHEADERDATA_INFOMASK 3 |
| uint16 t_infomask; /* various flag bits, see below */ |
| |
| #define FIELDNO_HEAPTUPLEHEADERDATA_HOFF 4 |
| uint8 t_hoff; /* sizeof header incl. bitmap, padding */ |
| |
| /* ^ - 23 bytes - ^ */ |
| |
| #define FIELDNO_HEAPTUPLEHEADERDATA_BITS 5 |
| bits8 t_bits[FLEXIBLE_ARRAY_MEMBER]; /* bitmap of NULLs */ |
| |
| /* MORE DATA FOLLOWS AT END OF STRUCT */ |
| }; |
| |
| /* typedef appears in htup.h */ |
| |
| #define SizeofHeapTupleHeader offsetof(HeapTupleHeaderData, t_bits) |
| |
| /* |
| * 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_OLD 0x0008 /* has an object-id field */ |
| #define HEAP_XMAX_KEYSHR_LOCK 0x0010 /* xmax is a key-shared locker */ |
| #define HEAP_COMBOCID 0x0020 /* t_cid is a combo cid */ |
| #define HEAP_XMAX_EXCL_LOCK 0x0040 /* xmax is exclusive locker */ |
| #define HEAP_XMAX_LOCK_ONLY 0x0080 /* xmax, if valid, is only a locker */ |
| |
| /* xmax is a shared locker */ |
| #define HEAP_XMAX_SHR_LOCK (HEAP_XMAX_EXCL_LOCK | HEAP_XMAX_KEYSHR_LOCK) |
| |
| #define HEAP_LOCK_MASK (HEAP_XMAX_SHR_LOCK | HEAP_XMAX_EXCL_LOCK | \ |
| HEAP_XMAX_KEYSHR_LOCK) |
| #define HEAP_XMIN_COMMITTED 0x0100 /* t_xmin committed */ |
| #define HEAP_XMIN_INVALID 0x0200 /* t_xmin invalid/aborted */ |
| #define HEAP_XMIN_FROZEN (HEAP_XMIN_COMMITTED|HEAP_XMIN_INVALID) |
| #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 pre-9.0 |
| * VACUUM FULL; kept for binary |
| * upgrade support */ |
| #define HEAP_MOVED_IN 0x8000 /* moved from another place by pre-9.0 |
| * VACUUM FULL; kept for binary |
| * upgrade support */ |
| #define HEAP_MOVED (HEAP_MOVED_OFF | HEAP_MOVED_IN) |
| |
| #define HEAP_XACT_MASK 0xFFF0 /* visibility-related bits */ |
| |
| /* |
| * A tuple is only locked (i.e. not updated by its Xmax) if the |
| * HEAP_XMAX_LOCK_ONLY bit is set; or, for pg_upgrade's sake, if the Xmax is |
| * not a multi and the EXCL_LOCK bit is set. |
| * |
| * See also HeapTupleHeaderIsOnlyLocked, which also checks for a possible |
| * aborted updater transaction. |
| * |
| * Beware of multiple evaluations of the argument. |
| */ |
| #define HEAP_XMAX_IS_LOCKED_ONLY(infomask) \ |
| (((infomask) & HEAP_XMAX_LOCK_ONLY) || \ |
| (((infomask) & (HEAP_XMAX_IS_MULTI | HEAP_LOCK_MASK)) == HEAP_XMAX_EXCL_LOCK)) |
| |
| /* |
| * A tuple that has HEAP_XMAX_IS_MULTI and HEAP_XMAX_LOCK_ONLY but neither of |
| * HEAP_XMAX_EXCL_LOCK and HEAP_XMAX_KEYSHR_LOCK must come from a tuple that was |
| * share-locked in 9.2 or earlier and then pg_upgrade'd. |
| * |
| * In 9.2 and prior, HEAP_XMAX_IS_MULTI was only set when there were multiple |
| * FOR SHARE lockers of that tuple. That set HEAP_XMAX_LOCK_ONLY (with a |
| * different name back then) but neither of HEAP_XMAX_EXCL_LOCK and |
| * HEAP_XMAX_KEYSHR_LOCK. That combination is no longer possible in 9.3 and |
| * up, so if we see that combination we know for certain that the tuple was |
| * locked in an earlier release; since all such lockers are gone (they cannot |
| * survive through pg_upgrade), such tuples can safely be considered not |
| * locked. |
| * |
| * We must not resolve such multixacts locally, because the result would be |
| * bogus, regardless of where they stand with respect to the current valid |
| * multixact range. |
| */ |
| #define HEAP_LOCKED_UPGRADED(infomask) \ |
| ( \ |
| ((infomask) & HEAP_XMAX_IS_MULTI) != 0 && \ |
| ((infomask) & HEAP_XMAX_LOCK_ONLY) != 0 && \ |
| (((infomask) & (HEAP_XMAX_EXCL_LOCK | HEAP_XMAX_KEYSHR_LOCK)) == 0) \ |
| ) |
| |
| /* |
| * Use these to test whether a particular lock is applied to a tuple |
| */ |
| #define HEAP_XMAX_IS_SHR_LOCKED(infomask) \ |
| (((infomask) & HEAP_LOCK_MASK) == HEAP_XMAX_SHR_LOCK) |
| #define HEAP_XMAX_IS_EXCL_LOCKED(infomask) \ |
| (((infomask) & HEAP_LOCK_MASK) == HEAP_XMAX_EXCL_LOCK) |
| #define HEAP_XMAX_IS_KEYSHR_LOCKED(infomask) \ |
| (((infomask) & HEAP_LOCK_MASK) == HEAP_XMAX_KEYSHR_LOCK) |
| |
| /* turn these all off when Xmax is to change */ |
| #define HEAP_XMAX_BITS (HEAP_XMAX_COMMITTED | HEAP_XMAX_INVALID | \ |
| HEAP_XMAX_IS_MULTI | HEAP_LOCK_MASK | HEAP_XMAX_LOCK_ONLY) |
| |
| /* |
| * information stored in t_infomask2: |
| */ |
| #define HEAP_NATTS_MASK 0x07FF /* 11 bits for number of attributes */ |
| /* bits 0x1800 are available */ |
| #define HEAP_KEYS_UPDATED 0x2000 /* tuple was updated and key cols |
| * modified, or tuple deleted */ |
| #define HEAP_HOT_UPDATED 0x4000 /* tuple was HOT-updated */ |
| #define HEAP_ONLY_TUPLE 0x8000 /* this is heap-only tuple */ |
| |
| #define HEAP2_XACT_MASK 0xE000 /* visibility-related bits */ |
| |
| /* |
| * HEAP_TUPLE_HAS_MATCH is a temporary flag used during hash joins. It is |
| * only used in tuples that are in the hash table, and those don't need |
| * any visibility information, so we can overlay it on a visibility flag |
| * instead of using up a dedicated bit. |
| */ |
| #define HEAP_TUPLE_HAS_MATCH HEAP_ONLY_TUPLE /* tuple has a join match */ |
| |
| /* |
| * HeapTupleHeader accessor macros |
| * |
| * Note: beware of multiple evaluations of "tup" argument. But the Set |
| * macros evaluate their other argument only once. |
| */ |
| |
| /* |
| * HeapTupleHeaderGetRawXmin returns the "raw" xmin field, which is the xid |
| * originally used to insert the tuple. However, the tuple might actually |
| * be frozen (via HeapTupleHeaderSetXminFrozen) in which case the tuple's xmin |
| * is visible to every snapshot. Prior to PostgreSQL 9.4, we actually changed |
| * the xmin to FrozenTransactionId, and that value may still be encountered |
| * on disk. |
| */ |
| #define HeapTupleHeaderGetRawXmin(tup) \ |
| ( \ |
| (tup)->t_choice.t_heap.t_xmin \ |
| ) |
| |
| #define HeapTupleHeaderGetXmin(tup) \ |
| ( \ |
| HeapTupleHeaderXminFrozen(tup) ? \ |
| FrozenTransactionId : HeapTupleHeaderGetRawXmin(tup) \ |
| ) |
| |
| #define HeapTupleHeaderSetXmin(tup, xid) \ |
| ( \ |
| (tup)->t_choice.t_heap.t_xmin = (xid) \ |
| ) |
| |
| #define HeapTupleHeaderXminCommitted(tup) \ |
| ( \ |
| ((tup)->t_infomask & HEAP_XMIN_COMMITTED) != 0 \ |
| ) |
| |
| #define HeapTupleHeaderXminInvalid(tup) \ |
| ( \ |
| ((tup)->t_infomask & (HEAP_XMIN_COMMITTED|HEAP_XMIN_INVALID)) == \ |
| HEAP_XMIN_INVALID \ |
| ) |
| |
| #define HeapTupleHeaderXminFrozen(tup) \ |
| ( \ |
| ((tup)->t_infomask & (HEAP_XMIN_FROZEN)) == HEAP_XMIN_FROZEN \ |
| ) |
| |
| #define HeapTupleHeaderSetXminCommitted(tup) \ |
| ( \ |
| AssertMacro(!HeapTupleHeaderXminInvalid(tup)), \ |
| ((tup)->t_infomask |= HEAP_XMIN_COMMITTED) \ |
| ) |
| |
| #define HeapTupleHeaderSetXminInvalid(tup) \ |
| ( \ |
| AssertMacro(!HeapTupleHeaderXminCommitted(tup)), \ |
| ((tup)->t_infomask |= HEAP_XMIN_INVALID) \ |
| ) |
| |
| #define HeapTupleHeaderSetXminFrozen(tup) \ |
| ( \ |
| AssertMacro(!HeapTupleHeaderXminInvalid(tup)), \ |
| ((tup)->t_infomask |= HEAP_XMIN_FROZEN) \ |
| ) |
| |
| /* |
| * HeapTupleHeaderGetRawXmax gets you the raw Xmax field. To find out the Xid |
| * that updated a tuple, you might need to resolve the MultiXactId if certain |
| * bits are set. HeapTupleHeaderGetUpdateXid checks those bits and takes care |
| * to resolve the MultiXactId if necessary. This might involve multixact I/O, |
| * so it should only be used if absolutely necessary. |
| */ |
| #define HeapTupleHeaderGetUpdateXid(tup) \ |
| ( \ |
| (!((tup)->t_infomask & HEAP_XMAX_INVALID) && \ |
| ((tup)->t_infomask & HEAP_XMAX_IS_MULTI) && \ |
| !((tup)->t_infomask & HEAP_XMAX_LOCK_ONLY)) ? \ |
| HeapTupleGetUpdateXid(tup) \ |
| : \ |
| HeapTupleHeaderGetRawXmax(tup) \ |
| ) |
| |
| #define HeapTupleHeaderGetRawXmax(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 HeapTupleHeaderIsSpeculative(tup) \ |
| ( \ |
| (ItemPointerGetOffsetNumberNoCheck(&(tup)->t_ctid) == SpecTokenOffsetNumber) \ |
| ) |
| |
| #define HeapTupleHeaderGetSpeculativeToken(tup) \ |
| ( \ |
| AssertMacro(HeapTupleHeaderIsSpeculative(tup)), \ |
| ItemPointerGetBlockNumber(&(tup)->t_ctid) \ |
| ) |
| |
| #define HeapTupleHeaderSetSpeculativeToken(tup, token) \ |
| ( \ |
| ItemPointerSet(&(tup)->t_ctid, token, SpecTokenOffsetNumber) \ |
| ) |
| |
| #define HeapTupleHeaderIndicatesMovedPartitions(tup) \ |
| (ItemPointerGetOffsetNumber(&(tup)->t_ctid) == MovedPartitionsOffsetNumber && \ |
| ItemPointerGetBlockNumberNoCheck(&(tup)->t_ctid) == MovedPartitionsBlockNumber) |
| |
| #define HeapTupleHeaderSetMovedPartitions(tup) \ |
| ItemPointerSet(&(tup)->t_ctid, MovedPartitionsBlockNumber, MovedPartitionsOffsetNumber) |
| |
| #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) \ |
| ) |
| |
| /* |
| * 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_XMAX_INVALID) == 0 && \ |
| !HeapTupleHeaderXminInvalid(tup) \ |
| ) |
| |
| #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) != 0 \ |
| ) |
| |
| #define HeapTupleHeaderSetHeapOnly(tup) \ |
| ( \ |
| (tup)->t_infomask2 |= HEAP_ONLY_TUPLE \ |
| ) |
| |
| #define HeapTupleHeaderClearHeapOnly(tup) \ |
| ( \ |
| (tup)->t_infomask2 &= ~HEAP_ONLY_TUPLE \ |
| ) |
| |
| #define HeapTupleHeaderHasMatch(tup) \ |
| ( \ |
| ((tup)->t_infomask2 & HEAP_TUPLE_HAS_MATCH) != 0 \ |
| ) |
| |
| #define HeapTupleHeaderSetMatch(tup) \ |
| ( \ |
| (tup)->t_infomask2 |= HEAP_TUPLE_HAS_MATCH \ |
| ) |
| |
| #define HeapTupleHeaderClearMatch(tup) \ |
| ( \ |
| (tup)->t_infomask2 &= ~HEAP_TUPLE_HAS_MATCH \ |
| ) |
| |
| #define HeapTupleHeaderGetNatts(tup) \ |
| ((tup)->t_infomask2 & HEAP_NATTS_MASK) |
| |
| #define HeapTupleHeaderSetNatts(tup, natts) \ |
| ( \ |
| (tup)->t_infomask2 = ((tup)->t_infomask2 & ~HEAP_NATTS_MASK) | (natts) \ |
| ) |
| |
| #define HeapTupleHeaderHasExternal(tup) \ |
| (((tup)->t_infomask & HEAP_HASEXTERNAL) != 0) |
| |
| |
| /* |
| * 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 allow for the ItemId that must point to the tuple, ensuring that |
| * an otherwise-empty page can indeed hold a tuple of this size. Because |
| * ItemIds and tuples have different alignment requirements, don't assume that |
| * you can, say, fit 2 tuples of size MaxHeapTupleSize/2 on the same page. |
| */ |
| #define MaxHeapTupleSize (BLCKSZ - MAXALIGN(SizeOfPageHeaderData + sizeof(ItemIdData))) |
| #define MinHeapTupleSize MAXALIGN(SizeofHeapTupleHeader) |
| |
| /* |
| * 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 line 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 - SizeOfPageHeaderData) / \ |
| (MAXALIGN(SizeofHeapTupleHeader) + 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) |
| |
| |
| /* |
| * 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. |
| * |
| * MINIMAL_TUPLE_DATA_OFFSET is the offset to the first useful (non-pad) data |
| * other than the length word. tuplesort.c and tuplestore.c use this to avoid |
| * writing the padding to disk. |
| */ |
| #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) |
| #define MINIMAL_TUPLE_DATA_OFFSET \ |
| offsetof(MinimalTupleData, t_infomask2) |
| |
| 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[FLEXIBLE_ARRAY_MEMBER]; /* bitmap of NULLs */ |
| |
| /* MORE DATA FOLLOWS AT END OF STRUCT */ |
| }; |
| |
| /* typedef appears in htup.h */ |
| |
| #define SizeofMinimalTupleHeader offsetof(MinimalTupleData, t_bits) |
| |
| |
| /* |
| * 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 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) |
| |
| |
| /* ---------------- |
| * fastgetattr |
| * |
| * Fetch a user attribute's value as a Datum (might be either a |
| * value, or a pointer into the data area of the tuple). |
| * |
| * This must not be used when a system attribute might be requested. |
| * Furthermore, the passed attnum MUST be valid. Use heap_getattr() |
| * instead, if in doubt. |
| * |
| * This gets called many times, so we macro the cacheable and NULL |
| * lookups, and call nocachegetattr() for the rest. |
| * ---------------- |
| */ |
| |
| #if !defined(DISABLE_COMPLEX_MACRO) |
| |
| #define fastgetattr(tup, attnum, tupleDesc, isnull) \ |
| ( \ |
| AssertMacro((attnum) > 0), \ |
| (*(isnull) = false), \ |
| HeapTupleNoNulls(tup) ? \ |
| ( \ |
| TupleDescAttr((tupleDesc), (attnum)-1)->attcacheoff >= 0 ? \ |
| ( \ |
| fetchatt(TupleDescAttr((tupleDesc), (attnum)-1), \ |
| (char *) (tup)->t_data + (tup)->t_data->t_hoff + \ |
| TupleDescAttr((tupleDesc), (attnum)-1)->attcacheoff)\ |
| ) \ |
| : \ |
| nocachegetattr((tup), (attnum), (tupleDesc)) \ |
| ) \ |
| : \ |
| ( \ |
| att_isnull((attnum)-1, (tup)->t_data->t_bits) ? \ |
| ( \ |
| (*(isnull) = true), \ |
| (Datum)NULL \ |
| ) \ |
| : \ |
| ( \ |
| nocachegetattr((tup), (attnum), (tupleDesc)) \ |
| ) \ |
| ) \ |
| ) |
| #else /* defined(DISABLE_COMPLEX_MACRO) */ |
| |
| extern Datum fastgetattr(HeapTuple tup, int attnum, TupleDesc tupleDesc, |
| bool *isnull); |
| #endif /* defined(DISABLE_COMPLEX_MACRO) */ |
| |
| |
| /* ---------------- |
| * heap_getattr |
| * |
| * Extract an attribute of a heap tuple and return it as a Datum. |
| * This works for either system or user attributes. The given attnum |
| * is properly range-checked. |
| * |
| * If the field in question has a NULL value, we return a zero Datum |
| * and set *isnull == true. Otherwise, we set *isnull == false. |
| * |
| * <tup> is the pointer to the heap tuple. <attnum> is the attribute |
| * number of the column (field) caller wants. <tupleDesc> is a |
| * pointer to the structure describing the row and all its fields. |
| * ---------------- |
| */ |
| #define heap_getattr(tup, attnum, tupleDesc, isnull) \ |
| ( \ |
| ((attnum) > 0) ? \ |
| ( \ |
| ((attnum) > (int) HeapTupleHeaderGetNatts((tup)->t_data)) ? \ |
| getmissingattr((tupleDesc), (attnum), (isnull)) \ |
| : \ |
| fastgetattr((tup), (attnum), (tupleDesc), (isnull)) \ |
| ) \ |
| : \ |
| heap_getsysattr((tup), (attnum), (tupleDesc), (isnull)) \ |
| ) |
| |
| |
| /* prototypes for functions in common/heaptuple.c */ |
| extern Size heap_compute_data_size(TupleDesc tupleDesc, |
| Datum *values, bool *isnull); |
| extern void heap_fill_tuple(TupleDesc tupleDesc, |
| Datum *values, bool *isnull, |
| char *data, Size data_size, |
| uint16 *infomask, bits8 *bit); |
| extern bool heap_attisnull(HeapTuple tup, int attnum, TupleDesc tupleDesc); |
| extern Datum nocachegetattr(HeapTuple tup, int attnum, |
| TupleDesc att); |
| extern Datum heap_getsysattr(HeapTuple tup, int attnum, TupleDesc tupleDesc, |
| bool *isnull); |
| extern Datum getmissingattr(TupleDesc tupleDesc, |
| int attnum, bool *isnull); |
| extern HeapTuple heap_copytuple(HeapTuple tuple); |
| extern void heap_copytuple_with_tuple(HeapTuple src, HeapTuple dest); |
| extern Datum heap_copy_tuple_as_datum(HeapTuple tuple, TupleDesc tupleDesc); |
| extern HeapTuple heap_form_tuple(TupleDesc tupleDescriptor, |
| Datum *values, bool *isnull); |
| extern HeapTuple heap_modify_tuple(HeapTuple tuple, |
| TupleDesc tupleDesc, |
| Datum *replValues, |
| bool *replIsnull, |
| bool *doReplace); |
| extern HeapTuple heap_modify_tuple_by_cols(HeapTuple tuple, |
| TupleDesc tupleDesc, |
| int nCols, |
| int *replCols, |
| Datum *replValues, |
| bool *replIsnull); |
| extern void heap_deform_tuple(HeapTuple tuple, TupleDesc tupleDesc, |
| Datum *values, bool *isnull); |
| extern void heap_freetuple(HeapTuple htup); |
| extern MinimalTuple heap_form_minimal_tuple(TupleDesc tupleDescriptor, |
| Datum *values, bool *isnull); |
| extern void heap_free_minimal_tuple(MinimalTuple mtup); |
| extern MinimalTuple heap_copy_minimal_tuple(MinimalTuple mtup); |
| extern HeapTuple heap_tuple_from_minimal_tuple(MinimalTuple mtup); |
| extern MinimalTuple minimal_tuple_from_heap_tuple(HeapTuple htup); |
| extern size_t varsize_any(void *p); |
| extern HeapTuple heap_expand_tuple(HeapTuple sourceTuple, TupleDesc tupleDesc); |
| extern MinimalTuple minimal_expand_tuple(HeapTuple sourceTuple, TupleDesc tupleDesc); |
| |
| #endif /* HTUP_DETAILS_H */ |