/*
* Form a tuple for entry tree.
*
* On leaf pages, Index tuple has non-traditional layout. Tuple may contain
* posting list or root blocknumber of posting tree.
* Macros: GinIsPostingTree(itup) / GinSetPostingTree(itup, blkno)
* 1) Posting list
* - itup->t_info & INDEX_SIZE_MASK contains total size of tuple as usual
* - ItemPointerGetBlockNumber(&itup->t_tid) contains original
* size of tuple (without posting list).
* Macros: GinGetOrigSizePosting(itup) / GinSetOrigSizePosting(itup,n)
* - ItemPointerGetOffsetNumber(&itup->t_tid) contains number
* of elements in posting list (number of heap itempointers)
* Macros: GinGetNPosting(itup) / GinSetNPosting(itup,n)
* - After standard part of tuple there is a posting list, ie, array
* of heap itempointers
* Macros: GinGetPosting(itup)
* 2) Posting tree
* - itup->t_info & INDEX_SIZE_MASK contains size of tuple as usual
* - ItemPointerGetBlockNumber(&itup->t_tid) contains block number of
* root of posting tree
* - ItemPointerGetOffsetNumber(&itup->t_tid) contains magic number
* GIN_TREE_POSTING, which distinguishes this from posting-list case
*
* Attributes of an index tuple are different for single and multicolumn index.
* For single-column case, index tuple stores only value to be indexed.
* For multicolumn case, it stores two attributes: column number of value
* and value.
*/
IndexTuple
GinFormTuple(GinState *ginstate, OffsetNumber attnum, Datum key, ItemPointerData *ipd, uint32 nipd)
{
bool isnull[2] = {FALSE, FALSE};
IndexTuple itup;
if (ginstate->oneCol)
itup = index_form_tuple(ginstate->origTupdesc, &key, isnull);
else
{
Datum datums[2];
datums[0] = UInt16GetDatum(attnum);
datums[1] = key;
itup = index_form_tuple(ginstate->tupdesc[attnum - 1], datums, isnull);
}
GinSetOrigSizePosting(itup, IndexTupleSize(itup));
if (nipd > 0)
{
uint32 newsize = MAXALIGN(SHORTALIGN(IndexTupleSize(itup)) + sizeof(ItemPointerData) * nipd);
if (newsize >= INDEX_SIZE_MASK)
return NULL;
if (newsize > TOAST_INDEX_TARGET && nipd > 1)
return NULL;
itup = repalloc(itup, newsize);
/* set new size */
itup->t_info &= ~INDEX_SIZE_MASK;
itup->t_info |= newsize;
if (ipd)
memcpy(GinGetPosting(itup), ipd, sizeof(ItemPointerData) * nipd);
GinSetNPosting(itup, nipd);
}
else
{
GinSetNPosting(itup, 0);
}
return itup;
}
/*
* Form a tuple for entry tree.
*
* If the tuple would be too big to be stored, function throws a suitable
* error if errorTooBig is TRUE, or returns NULL if errorTooBig is FALSE.
*
* On leaf pages, Index tuple has non-traditional layout. Tuple may contain
* posting list or root blocknumber of posting tree.
* Macros: GinIsPostingTree(itup) / GinSetPostingTree(itup, blkno)
* 1) Posting list
* - itup->t_info & INDEX_SIZE_MASK contains total size of tuple as usual
* - ItemPointerGetBlockNumber(&itup->t_tid) contains original
* size of tuple (without posting list).
* Macros: GinGetOrigSizePosting(itup) / GinSetOrigSizePosting(itup,n)
* - ItemPointerGetOffsetNumber(&itup->t_tid) contains number
* of elements in posting list (number of heap itempointers)
* Macros: GinGetNPosting(itup) / GinSetNPosting(itup,n)
* - After standard part of tuple there is a posting list, ie, array
* of heap itempointers
* Macros: GinGetPosting(itup)
* 2) Posting tree
* - itup->t_info & INDEX_SIZE_MASK contains size of tuple as usual
* - ItemPointerGetBlockNumber(&itup->t_tid) contains block number of
* root of posting tree
* - ItemPointerGetOffsetNumber(&itup->t_tid) contains magic number
* GIN_TREE_POSTING, which distinguishes this from posting-list case
*
* Attributes of an index tuple are different for single and multicolumn index.
* For single-column case, index tuple stores only value to be indexed.
* For multicolumn case, it stores two attributes: column number of value
* and value.
*/
IndexTuple
GinFormTuple(Relation index, GinState *ginstate,
OffsetNumber attnum, Datum key,
ItemPointerData *ipd, uint32 nipd, bool errorTooBig)
{
bool isnull[2] = {FALSE, FALSE};
IndexTuple itup;
uint32 newsize;
if (ginstate->oneCol)
itup = index_form_tuple(ginstate->origTupdesc, &key, isnull);
else
{
Datum datums[2];
datums[0] = UInt16GetDatum(attnum);
datums[1] = key;
itup = index_form_tuple(ginstate->tupdesc[attnum - 1], datums, isnull);
}
GinSetOrigSizePosting(itup, IndexTupleSize(itup));
if (nipd > 0)
{
newsize = MAXALIGN(SHORTALIGN(IndexTupleSize(itup)) + sizeof(ItemPointerData) * nipd);
if (newsize > Min(INDEX_SIZE_MASK, GinMaxItemSize))
{
if (errorTooBig)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("index row size %lu exceeds maximum %lu for index \"%s\"",
(unsigned long) newsize,
(unsigned long) Min(INDEX_SIZE_MASK,
GinMaxItemSize),
RelationGetRelationName(index))));
return NULL;
}
itup = repalloc(itup, newsize);
/* set new size */
itup->t_info &= ~INDEX_SIZE_MASK;
itup->t_info |= newsize;
if (ipd)
memcpy(GinGetPosting(itup), ipd, sizeof(ItemPointerData) * nipd);
GinSetNPosting(itup, nipd);
}
else
{
/*
* Gin tuple without any ItemPointers should be large enough to keep
* one ItemPointer, to prevent inconsistency between
* ginHeapTupleFastCollect and ginEntryInsert called by
* ginHeapTupleInsert. ginHeapTupleFastCollect forms tuple without
* extra pointer to heap, but ginEntryInsert (called for pending list
* cleanup during vacuum) will form the same tuple with one
* ItemPointer.
*/
newsize = MAXALIGN(SHORTALIGN(IndexTupleSize(itup)) + sizeof(ItemPointerData));
if (newsize > Min(INDEX_SIZE_MASK, GinMaxItemSize))
{
if (errorTooBig)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("index row size %lu exceeds maximum %lu for index \"%s\"",
(unsigned long) newsize,
(unsigned long) Min(INDEX_SIZE_MASK,
GinMaxItemSize),
RelationGetRelationName(index))));
return NULL;
}
GinSetNPosting(itup, 0);
}
return itup;
}
