/*
* brin_deconstruct_tuple
* Guts of attribute extraction from an on-disk BRIN tuple.
*
* Its arguments are:
* brdesc BRIN descriptor for the stored tuple
* tp pointer to the tuple data area
* nullbits pointer to the tuple nulls bitmask
* nulls "has nulls" bit in tuple infomask
* values output values, array of size brdesc->bd_totalstored
* allnulls output "allnulls", size brdesc->bd_tupdesc->natts
* hasnulls output "hasnulls", size brdesc->bd_tupdesc->natts
*
* Output arrays must have been allocated by caller.
*/
static inline void
brin_deconstruct_tuple(BrinDesc *brdesc,
char *tp, bits8 *nullbits, bool nulls,
Datum *values, bool *allnulls, bool *hasnulls)
{
int attnum;
int stored;
TupleDesc diskdsc;
long off;
/*
* First iterate to natts to obtain both null flags for each attribute.
* Note that we reverse the sense of the att_isnull test, because we store
* 1 for a null value (rather than a 1 for a not null value as is the
* att_isnull convention used elsewhere.) See brin_form_tuple.
*/
for (attnum = 0; attnum < brdesc->bd_tupdesc->natts; attnum++)
{
/*
* the "all nulls" bit means that all values in the page range for
* this column are nulls. Therefore there are no values in the tuple
* data area.
*/
allnulls[attnum] = nulls && !att_isnull(attnum, nullbits);
/*
* the "has nulls" bit means that some tuples have nulls, but others
* have not-null values. Therefore we know the tuple contains data
* for this column.
*
* The hasnulls bits follow the allnulls bits in the same bitmask.
*/
hasnulls[attnum] =
nulls && !att_isnull(brdesc->bd_tupdesc->natts + attnum, nullbits);
}
/*
* Iterate to obtain each attribute's stored values. Note that since we
* may reuse attribute entries for more than one column, we cannot cache
* offsets here.
*/
diskdsc = brtuple_disk_tupdesc(brdesc);
stored = 0;
off = 0;
for (attnum = 0; attnum < brdesc->bd_tupdesc->natts; attnum++)
{
int datumno;
if (allnulls[attnum])
{
stored += brdesc->bd_info[attnum]->oi_nstored;
continue;
}
for (datumno = 0;
datumno < brdesc->bd_info[attnum]->oi_nstored;
datumno++)
{
Form_pg_attribute thisatt = TupleDescAttr(diskdsc, stored);
if (thisatt->attlen == -1)
{
off = att_align_pointer(off, thisatt->attalign, -1,
tp + off);
}
else
{
/* not varlena, so safe to use att_align_nominal */
off = att_align_nominal(off, thisatt->attalign);
}
values[stored++] = fetchatt(thisatt, tp + off);
off = att_addlength_pointer(off, thisatt->attlen, tp + off);
}
}
}
/*
* Convert an index tuple into Datum/isnull arrays.
*
* The caller must allocate sufficient storage for the output arrays.
* (INDEX_MAX_KEYS entries should be enough.)
*
* This is nearly the same as heap_deform_tuple(), but for IndexTuples.
* One difference is that the tuple should never have any missing columns.
*/
void
index_deform_tuple(IndexTuple tup, TupleDesc tupleDescriptor,
Datum *values, bool *isnull)
{
int hasnulls = IndexTupleHasNulls(tup);
int natts = tupleDescriptor->natts; /* number of atts to extract */
int attnum;
char *tp; /* ptr to tuple data */
int off; /* offset in tuple data */
bits8 *bp; /* ptr to null bitmap in tuple */
bool slow = false; /* can we use/set attcacheoff? */
/* Assert to protect callers who allocate fixed-size arrays */
Assert(natts <= INDEX_MAX_KEYS);
/* XXX "knows" t_bits are just after fixed tuple header! */
bp = (bits8 *) ((char *) tup + sizeof(IndexTupleData));
tp = (char *) tup + IndexInfoFindDataOffset(tup->t_info);
off = 0;
for (attnum = 0; attnum < natts; attnum++)
{
Form_pg_attribute thisatt = TupleDescAttr(tupleDescriptor, attnum);
if (hasnulls && att_isnull(attnum, bp))
{
values[attnum] = (Datum) 0;
isnull[attnum] = true;
slow = true; /* can't use attcacheoff anymore */
continue;
}
isnull[attnum] = false;
if (!slow && thisatt->attcacheoff >= 0)
off = thisatt->attcacheoff;
else if (thisatt->attlen == -1)
{
/*
* We can only cache the offset for a varlena attribute if the
* offset is already suitably aligned, so that there would be no
* pad bytes in any case: then the offset will be valid for either
* an aligned or unaligned value.
*/
if (!slow &&
off == att_align_nominal(off, thisatt->attalign))
thisatt->attcacheoff = off;
else
{
off = att_align_pointer(off, thisatt->attalign, -1,
tp + off);
slow = true;
}
}
else
{
/* not varlena, so safe to use att_align_nominal */
off = att_align_nominal(off, thisatt->attalign);
if (!slow)
thisatt->attcacheoff = off;
}
values[attnum] = fetchatt(thisatt, tp + off);
off = att_addlength_pointer(off, thisatt->attlen, tp + off);
if (thisatt->attlen <= 0)
slow = true; /* can't use attcacheoff anymore */
}
}
/* ----------------
* nocache_index_getattr
*
* This gets called from index_getattr() macro, and only in cases
* where we can't use cacheoffset and the value is not null.
*
* This caches attribute offsets in the attribute descriptor.
*
* An alternative way to speed things up would be to cache offsets
* with the tuple, but that seems more difficult unless you take
* the storage hit of actually putting those offsets into the
* tuple you send to disk. Yuck.
*
* This scheme will be slightly slower than that, but should
* perform well for queries which hit large #'s of tuples. After
* you cache the offsets once, examining all the other tuples using
* the same attribute descriptor will go much quicker. -cim 5/4/91
* ----------------
*/
Datum
nocache_index_getattr(IndexTuple tup,
int attnum,
TupleDesc tupleDesc)
{
Form_pg_attribute *att = tupleDesc->attrs;
char *tp; /* ptr to data part of tuple */
bits8 *bp = NULL; /* ptr to null bitmap in tuple */
bool slow = false; /* do we have to walk attrs? */
int data_off; /* tuple data offset */
int off; /* current offset within data */
/* ----------------
* Three cases:
*
* 1: No nulls and no variable-width attributes.
* 2: Has a null or a var-width AFTER att.
* 3: Has nulls or var-widths BEFORE att.
* ----------------
*/
data_off = IndexInfoFindDataOffset(tup->t_info);
attnum--;
if (IndexTupleHasNulls(tup))
{
/*
* there's a null somewhere in the tuple
*
* check to see if desired att is null
*/
/* XXX "knows" t_bits are just after fixed tuple header! */
bp = (bits8 *) ((char *) tup + sizeof(IndexTupleData));
/*
* Now check to see if any preceding bits are null...
*/
{
int byte = attnum >> 3;
int finalbit = attnum & 0x07;
/* check for nulls "before" final bit of last byte */
if ((~bp[byte]) & ((1 << finalbit) - 1))
slow = true;
else
{
/* check for nulls in any "earlier" bytes */
int i;
for (i = 0; i < byte; i++)
{
if (bp[i] != 0xFF)
{
slow = true;
break;
}
}
}
}
}
tp = (char *) tup + data_off;
if (!slow)
{
/*
* If we get here, there are no nulls up to and including the target
* attribute. If we have a cached offset, we can use it.
*/
if (att[attnum]->attcacheoff >= 0)
{
return fetchatt(att[attnum],
tp + att[attnum]->attcacheoff);
}
/*
* Otherwise, check for non-fixed-length attrs up to and including
* target. If there aren't any, it's safe to cheaply initialize the
* cached offsets for these attrs.
*/
if (IndexTupleHasVarwidths(tup))
{
int j;
for (j = 0; j <= attnum; j++)
{
if (att[j]->attlen <= 0)
{
slow = true;
break;
}
}
}
}
if (!slow)
{
int natts = tupleDesc->natts;
int j = 1;
/*
* If we get here, we have a tuple with no nulls or var-widths up to
* and including the target attribute, so we can use the cached offset
* ... only we don't have it yet, or we'd not have got here. Since
* it's cheap to compute offsets for fixed-width columns, we take the
* opportunity to initialize the cached offsets for *all* the leading
* fixed-width columns, in hope of avoiding future visits to this
* routine.
*/
att[0]->attcacheoff = 0;
/* we might have set some offsets in the slow path previously */
while (j < natts && att[j]->attcacheoff > 0)
j++;
off = att[j - 1]->attcacheoff + att[j - 1]->attlen;
for (; j < natts; j++)
{
if (att[j]->attlen <= 0)
break;
off = att_align_nominal(off, att[j]->attalign);
att[j]->attcacheoff = off;
off += att[j]->attlen;
}
Assert(j > attnum);
off = att[attnum]->attcacheoff;
}
else
{
bool usecache = true;
int i;
/*
* Now we know that we have to walk the tuple CAREFULLY. But we still
* might be able to cache some offsets for next time.
*
* Note - This loop is a little tricky. For each non-null attribute,
* we have to first account for alignment padding before the attr,
* then advance over the attr based on its length. Nulls have no
* storage and no alignment padding either. We can use/set
* attcacheoff until we reach either a null or a var-width attribute.
*/
off = 0;
for (i = 0;; i++) /* loop exit is at "break" */
{
if (IndexTupleHasNulls(tup) && att_isnull(i, bp))
{
usecache = false;
continue; /* this cannot be the target att */
}
/* If we know the next offset, we can skip the rest */
if (usecache && att[i]->attcacheoff >= 0)
off = att[i]->attcacheoff;
else if (att[i]->attlen == -1)
{
/*
* We can only cache the offset for a varlena attribute if the
* offset is already suitably aligned, so that there would be
* no pad bytes in any case: then the offset will be valid for
* either an aligned or unaligned value.
*/
if (usecache &&
off == att_align_nominal(off, att[i]->attalign))
att[i]->attcacheoff = off;
else
{
off = att_align_pointer(off, att[i]->attalign, -1,
tp + off);
usecache = false;
}
}
else
{
/* not varlena, so safe to use att_align_nominal */
off = att_align_nominal(off, att[i]->attalign);
if (usecache)
att[i]->attcacheoff = off;
}
if (i == attnum)
break;
off = att_addlength_pointer(off, att[i]->attlen, tp + off);
if (usecache && att[i]->attlen <= 0)
usecache = false;
}
}
return fetchatt(att[attnum], tp + off);
}
/*
* slot_deform_tuple
* Given a TupleTableSlot, extract data from the slot's physical tuple
* into its Datum/isnull arrays. Data is extracted up through the
* natts'th column (caller must ensure this is a legal column number).
*
* This is essentially an incremental version of heap_deform_tuple:
* on each call we extract attributes up to the one needed, without
* re-computing information about previously extracted attributes.
* slot->tts_nvalid is the number of attributes already extracted.
*/
static void
slot_deform_tuple(TupleTableSlot *slot, int natts)
{
HeapTuple tuple = TupGetHeapTuple(slot);
TupleDesc tupleDesc = slot->tts_tupleDescriptor;
Datum *values = slot->PRIVATE_tts_values;
bool *isnull = slot->PRIVATE_tts_isnull;
HeapTupleHeader tup = tuple->t_data;
bool hasnulls = HeapTupleHasNulls(tuple);
Form_pg_attribute *att = tupleDesc->attrs;
int attnum;
char *tp; /* ptr to tuple data */
long off; /* offset in tuple data */
bits8 *bp = tup->t_bits; /* ptr to null bitmap in tuple */
bool slow; /* can we use/set attcacheoff? */
/*
* Check whether the first call for this tuple, and initialize or restore
* loop state.
*/
attnum = slot->PRIVATE_tts_nvalid;
if (attnum == 0)
{
/* Start from the first attribute */
off = 0;
slow = false;
}
else
{
/* Restore state from previous execution */
off = slot->PRIVATE_tts_off;
slow = slot->PRIVATE_tts_slow;
}
tp = (char *) tup + tup->t_hoff;
for (; attnum < natts; attnum++)
{
Form_pg_attribute thisatt = att[attnum];
if (hasnulls && att_isnull(attnum, bp))
{
values[attnum] = (Datum) 0;
isnull[attnum] = true;
slow = true; /* can't use attcacheoff anymore */
continue;
}
isnull[attnum] = false;
if (!slow && thisatt->attcacheoff >= 0)
off = thisatt->attcacheoff;
else if (thisatt->attlen == -1)
{
/*
* We can only cache the offset for a varlena attribute if the
* offset is already suitably aligned, so that there would be no
* pad bytes in any case: then the offset will be valid for either
* an aligned or unaligned value.
*/
if (!slow &&
off == att_align_nominal(off, thisatt->attalign))
thisatt->attcacheoff = off;
else
{
off = att_align_pointer(off, thisatt->attalign, -1,
tp + off);
slow = true;
}
}
else
{
/* not varlena, so safe to use att_align_nominal */
off = att_align_nominal(off, thisatt->attalign);
if (!slow)
thisatt->attcacheoff = off;
}
if (!slow && thisatt->attlen < 0)
slow = true;
values[attnum] = fetchatt(thisatt, tp + off);
off = att_addlength_pointer(off, thisatt->attlen, tp + off);
if (thisatt->attlen <= 0)
slow = true; /* can't use attcacheoff anymore */
}
/*
* Save state for next execution
*/
slot->PRIVATE_tts_nvalid = attnum;
slot->PRIVATE_tts_off = off;
slot->PRIVATE_tts_slow = slow;
}
/* ----------------
* nocache_index_getattr
*
* This gets called from index_getattr() macro, and only in cases
* where we can't use cacheoffset and the value is not null.
*
* This caches attribute offsets in the attribute descriptor.
*
* An alternate way to speed things up would be to cache offsets
* with the tuple, but that seems more difficult unless you take
* the storage hit of actually putting those offsets into the
* tuple you send to disk. Yuck.
*
* This scheme will be slightly slower than that, but should
* perform well for queries which hit large #'s of tuples. After
* you cache the offsets once, examining all the other tuples using
* the same attribute descriptor will go much quicker. -cim 5/4/91
* ----------------
*/
Datum
nocache_index_getattr(IndexTuple tup,
int attnum,
TupleDesc tupleDesc,
bool *isnull)
{
Form_pg_attribute *att = tupleDesc->attrs;
char *tp; /* ptr to att in tuple */
bits8 *bp = NULL; /* ptr to null bitmask in tuple */
bool slow = false; /* do we have to walk nulls? */
int data_off; /* tuple data offset */
(void) isnull; /* not used */
/*
* sanity checks
*/
/* ----------------
* Three cases:
*
* 1: No nulls and no variable-width attributes.
* 2: Has a null or a var-width AFTER att.
* 3: Has nulls or var-widths BEFORE att.
* ----------------
*/
#ifdef IN_MACRO
/* This is handled in the macro */
Assert(PointerIsValid(isnull));
Assert(attnum > 0);
*isnull = false;
#endif
data_off = IndexInfoFindDataOffset(tup->t_info);
attnum--;
if (!IndexTupleHasNulls(tup))
{
#ifdef IN_MACRO
/* This is handled in the macro */
if (att[attnum]->attcacheoff != -1)
{
return fetchatt(att[attnum],
(char *) tup + data_off +
att[attnum]->attcacheoff);
}
#endif
}
else
{
/*
* there's a null somewhere in the tuple
*
* check to see if desired att is null
*/
/* XXX "knows" t_bits are just after fixed tuple header! */
bp = (bits8 *) ((char *) tup + sizeof(IndexTupleData));
#ifdef IN_MACRO
/* This is handled in the macro */
if (att_isnull(attnum, bp))
{
*isnull = true;
return (Datum) NULL;
}
#endif
/*
* Now check to see if any preceding bits are null...
*/
{
int byte = attnum >> 3;
int finalbit = attnum & 0x07;
/* check for nulls "before" final bit of last byte */
if ((~bp[byte]) & ((1 << finalbit) - 1))
slow = true;
else
{
/* check for nulls in any "earlier" bytes */
int i;
for (i = 0; i < byte; i++)
{
if (bp[i] != 0xFF)
{
slow = true;
break;
}
}
}
}
}
tp = (char *) tup + data_off;
/*
* now check for any non-fixed length attrs before our attribute
*/
if (!slow)
{
if (att[attnum]->attcacheoff != -1)
{
return fetchatt(att[attnum],
tp + att[attnum]->attcacheoff);
}
else if (IndexTupleHasVarwidths(tup))
{
int j;
for (j = 0; j < attnum; j++)
{
if (att[j]->attlen <= 0)
{
slow = true;
break;
}
}
}
}
/*
* If slow is false, and we got here, we know that we have a tuple with no
* nulls or var-widths before the target attribute. If possible, we also
* want to initialize the remainder of the attribute cached offset values.
*/
if (!slow)
{
int j = 1;
long off;
/*
* need to set cache for some atts
*/
att[0]->attcacheoff = 0;
while (j < attnum && att[j]->attcacheoff > 0)
j++;
off = att[j - 1]->attcacheoff + att[j - 1]->attlen;
for (; j <= attnum; j++)
{
off = att_align(off, att[j]->attalign);
att[j]->attcacheoff = off;
off += att[j]->attlen;
}
return fetchatt(att[attnum], tp + att[attnum]->attcacheoff);
}
else
{
bool usecache = true;
int off = 0;
int i;
/*
* Now we know that we have to walk the tuple CAREFULLY.
*/
for (i = 0; i < attnum; i++)
{
if (IndexTupleHasNulls(tup))
{
if (att_isnull(i, bp))
{
usecache = false;
continue;
}
}
/* If we know the next offset, we can skip the rest */
if (usecache && att[i]->attcacheoff != -1)
off = att[i]->attcacheoff;
else
{
off = att_align(off, att[i]->attalign);
if (usecache)
att[i]->attcacheoff = off;
}
off = att_addlength(off, att[i]->attlen, tp + off);
if (usecache && att[i]->attlen <= 0)
usecache = false;
}
off = att_align(off, att[attnum]->attalign);
return fetchatt(att[attnum], tp + off);
}
}
/*
* heap_deformtuple
*
* Given a tuple, extract data into values/nulls arrays; this is
* the inverse of heap_formtuple.
*
* Storage for the values/nulls arrays is provided by the caller;
* it should be sized according to tupleDesc->natts not tuple->t_natts.
*
* Note that for pass-by-reference datatypes, the pointer placed
* in the Datum will point into the given tuple.
*
* When all or most of a tuple's fields need to be extracted,
* this routine will be significantly quicker than a loop around
* heap_getattr; the loop will become O(N^2) as soon as any
* noncacheable attribute offsets are involved.
*
* OLD API with char 'n'/' ' convention for indicating nulls.
* This is deprecated and should not be used in new code, but we keep it
* around for use by old add-on modules.
*/
void
heap_deformtuple(HeapTuple tuple,
TupleDesc tupleDesc,
Datum *values,
char *nulls)
{
HeapTupleHeader tup = tuple->t_data;
bool hasnulls = HeapTupleHasNulls(tuple);
Form_pg_attribute *att = tupleDesc->attrs;
int tdesc_natts = tupleDesc->natts;
int natts; /* number of atts to extract */
int attnum;
char *tp; /* ptr to tuple data */
long off; /* offset in tuple data */
bits8 *bp = tup->t_bits; /* ptr to null bitmap in tuple */
bool slow = false; /* can we use/set attcacheoff? */
natts = HeapTupleHeaderGetNatts(tup);
/*
* In inheritance situations, it is possible that the given tuple actually
* has more fields than the caller is expecting. Don't run off the end of
* the caller's arrays.
*/
natts = Min(natts, tdesc_natts);
tp = (char *) tup + tup->t_hoff;
off = 0;
for (attnum = 0; attnum < natts; attnum++)
{
Form_pg_attribute thisatt = att[attnum];
if (hasnulls && att_isnull(attnum, bp))
{
values[attnum] = (Datum) 0;
nulls[attnum] = 'n';
slow = true; /* can't use attcacheoff anymore */
continue;
}
nulls[attnum] = ' ';
if (!slow && thisatt->attcacheoff >= 0)
off = thisatt->attcacheoff;
else if (thisatt->attlen == -1)
{
/*
* We can only cache the offset for a varlena attribute if the
* offset is already suitably aligned, so that there would be no
* pad bytes in any case: then the offset will be valid for either
* an aligned or unaligned value.
*/
if (!slow &&
off == att_align_nominal(off, thisatt->attalign))
thisatt->attcacheoff = off;
else
{
off = att_align_pointer(off, thisatt->attalign, -1,
tp + off);
slow = true;
}
}
else
{
/* not varlena, so safe to use att_align_nominal */
off = att_align_nominal(off, thisatt->attalign);
if (!slow)
thisatt->attcacheoff = off;
}
values[attnum] = fetchatt(thisatt, tp + off);
off = att_addlength_pointer(off, thisatt->attlen, tp + off);
if (thisatt->attlen <= 0)
slow = true; /* can't use attcacheoff anymore */
}
/*
* If tuple doesn't have all the atts indicated by tupleDesc, read the
* rest as null
*/
for (; attnum < tdesc_natts; attnum++)
{
values[attnum] = (Datum) 0;
nulls[attnum] = 'n';
}
}
/*
* heap_deform_tuple
* Given a tuple, extract data into values/isnull arrays; this is
* the inverse of heap_form_tuple.
*
* Storage for the values/isnull arrays is provided by the caller;
* it should be sized according to tupleDesc->natts not tuple->t_natts.
*
* Note that for pass-by-reference datatypes, the pointer placed
* in the Datum will point into the given tuple.
*
* When all or most of a tuple's fields need to be extracted,
* this routine will be significantly quicker than a loop around
* heap_getattr; the loop will become O(N^2) as soon as any
* noncacheable attribute offsets are involved.
*/
void
heap_deform_tuple(HeapTuple tuple, TupleDesc tupleDesc,
Datum *values, bool *isnull)
{
HeapTupleHeader tup = tuple->t_data;
bool hasnulls = HeapTupleHasNulls(tuple);
Form_pg_attribute *att = tupleDesc->attrs;
int tdesc_natts = tupleDesc->natts;
int natts; /* number of atts to extract */
int attnum;
char *tp; /* ptr to tuple data */
long off; /* offset in tuple data */
bits8 *bp = tup->t_bits; /* ptr to null bitmap in tuple */
bool slow = false; /* can we use/set attcacheoff? */
Assert(!is_heaptuple_memtuple(tuple));
natts = HeapTupleHeaderGetNatts(tup);
/*
* In inheritance situations, it is possible that the given tuple actually
* has more fields than the caller is expecting. Don't run off the end of
* the caller's arrays.
*/
natts = Min(natts, tdesc_natts);
tp = (char *) tup + tup->t_hoff;
off = 0;
for (attnum = 0; attnum < natts; attnum++)
{
Form_pg_attribute thisatt = att[attnum];
if (hasnulls && att_isnull(attnum, bp))
{
values[attnum] = (Datum) 0;
isnull[attnum] = true;
slow = true; /* can't use attcacheoff anymore */
continue;
}
isnull[attnum] = false;
if (!slow && thisatt->attcacheoff >= 0)
off = thisatt->attcacheoff;
else if (thisatt->attlen == -1)
{
/*
* We can only cache the offset for a varlena attribute if the
* offset is already suitably aligned, so that there would be no
* pad bytes in any case: then the offset will be valid for either
* an aligned or unaligned value.
*/
if (!slow &&
off == att_align_nominal(off, thisatt->attalign))
thisatt->attcacheoff = off;
else
{
off = att_align_pointer(off, thisatt->attalign, -1,
tp + off);
slow = true;
}
}
else
{
/* not varlena, so safe to use att_align_nominal */
off = att_align_nominal(off, thisatt->attalign);
if (!slow)
thisatt->attcacheoff = off;
}
if (!slow && thisatt->attlen < 0)
slow = true;
values[attnum] = fetchatt(thisatt, tp + off);
#ifdef USE_ASSERT_CHECKING
/* Ignore attributes with dropped types */
if (thisatt->attlen == -1 && !thisatt->attisdropped)
{
Assert(VARATT_IS_SHORT(DatumGetPointer(values[attnum])) ||
!VARATT_CAN_MAKE_SHORT(DatumGetPointer(values[attnum])) ||
thisatt->atttypid == OIDVECTOROID ||
thisatt->atttypid == INT2VECTOROID ||
thisatt->atttypid >= FirstNormalObjectId);
}
#endif
off = att_addlength_pointer(off, thisatt->attlen, tp + off);
}
/*
* If tuple doesn't have all the atts indicated by tupleDesc, read the
* rest as null
*/
for (; attnum < tdesc_natts; attnum++)
{
values[attnum] = (Datum) 0;
isnull[attnum] = true;
}
}
/*
* heap_deform_tuple
* Given a tuple, extract data into values/isnull arrays; this is
* the inverse of heap_form_tuple.
*
* Storage for the values/isnull arrays is provided by the caller;
* it should be sized according to tupleDesc->natts not tuple->t_natts.
*
* Note that for pass-by-reference datatypes, the pointer placed
* in the Datum will point into the given tuple.
*
* When all or most of a tuple's fields need to be extracted,
* this routine will be significantly quicker than a loop around
* heap_getattr; the loop will become O(N^2) as soon as any
* noncacheable attribute offsets are involved.
*/
void
heap_deform_tuple(HeapTuple tuple, TupleDesc tupleDesc,
Datum *values, bool *isnull)
{
HeapTupleHeader tup = tuple->t_data;
bool hasnulls = HeapTupleHasNulls(tuple);
Form_pg_attribute *att = tupleDesc->attrs;
int tdesc_natts = tupleDesc->natts;
int natts; /* number of atts to extract */
int attnum;
char *tp; /* ptr to tuple data */
long off; /* offset in tuple data */
bits8 *bp = tup->t_bits; /* ptr to null bitmap in tuple */
bool slow = false; /* can we use/set attcacheoff? */
Assert(!is_heaptuple_memtuple(tuple));
natts = HeapTupleHeaderGetNatts(tup);
/*
* In inheritance situations, it is possible that the given tuple actually
* has more fields than the caller is expecting. Don't run off the end of
* the caller's arrays.
*/
natts = Min(natts, tdesc_natts);
tp = (char *) tup + tup->t_hoff;
off = 0;
for (attnum = 0; attnum < natts; attnum++)
{
Form_pg_attribute thisatt = att[attnum];
if (hasnulls && att_isnull(attnum, bp))
{
values[attnum] = (Datum) 0;
isnull[attnum] = true;
slow = true; /* can't use attcacheoff anymore */
continue;
}
isnull[attnum] = false;
if (!slow && thisatt->attcacheoff >= 0)
off = thisatt->attcacheoff;
else
{
/* if it's a varlena it may or may not be aligned, so check for
* something that looks like a padding byte before aligning. If
* we're already aligned it may be the leading byte of a 4-byte
* header but then the att_align is harmless. Don't bother looking
* if it's not a varlena though.*/
if (thisatt->attlen != -1 || !tp[off])
off = att_align(off, thisatt->attalign);
if (!slow && thisatt->attlen != -1)
thisatt->attcacheoff = off;
}
if (!slow && thisatt->attlen < 0)
slow = true;
values[attnum] = fetchatt(thisatt, tp + off);
#ifdef USE_ASSERT_CHECKING
/* Ignore attributes with dropped types */
if (thisatt->attlen == -1 && !thisatt->attisdropped)
{
Assert(VARATT_IS_SHORT_D(values[attnum]) ||
!VARATT_COULD_SHORT_D(values[attnum]) ||
thisatt->atttypid == OIDVECTOROID ||
thisatt->atttypid == INT2VECTOROID ||
thisatt->atttypid >= FirstNormalObjectId);
}
#endif
off = att_addlength(off, thisatt->attlen, PointerGetDatum(tp + off));
}
/*
* If tuple doesn't have all the atts indicated by tupleDesc, read the
* rest as null
*/
for (; attnum < tdesc_natts; attnum++)
{
values[attnum] = (Datum) 0;
isnull[attnum] = true;
}
}
/* ----------------
* nocachegetattr
*
* This only gets called from fastgetattr() macro, in cases where
* we can't use a cacheoffset and the value is not null.
*
* This caches attribute offsets in the attribute descriptor.
*
* An alternative way to speed things up would be to cache offsets
* with the tuple, but that seems more difficult unless you take
* the storage hit of actually putting those offsets into the
* tuple you send to disk. Yuck.
*
* This scheme will be slightly slower than that, but should
* perform well for queries which hit large #'s of tuples. After
* you cache the offsets once, examining all the other tuples using
* the same attribute descriptor will go much quicker. -cim 5/4/91
*
* NOTE: if you need to change this code, see also heap_deform_tuple.
* Also see nocache_index_getattr, which is the same code for index
* tuples.
* ----------------
*/
Datum
nocachegetattr(HeapTuple tuple,
int attnum,
TupleDesc tupleDesc)
{
HeapTupleHeader tup = tuple->t_data;
Form_pg_attribute *att = tupleDesc->attrs;
char *tp; /* ptr to att in tuple */
bits8 *bp = tup->t_bits; /* ptr to null bitmap in tuple */
bool slow = false; /* do we have to walk nulls? */
Assert(!is_heaptuple_memtuple(tuple));
/* If any cached offsets are there we can check that they make sense, but
* there may not be any at all, so pass -1 for the attnum we know is valid */
#ifdef IN_MACRO
/* This is handled in the macro */
Assert(attnum > 0);
if (isnull)
*isnull = false;
#endif
attnum--;
/* ----------------
* Three cases:
*
* 1: No nulls and no variable-width attributes.
* 2: Has a null or a var-width AFTER att.
* 3: Has nulls or var-widths BEFORE att.
* ----------------
*/
if (HeapTupleNoNulls(tuple))
{
#ifdef IN_MACRO
/* This is handled in the macro */
if (att[attnum]->attcacheoff != -1)
{
return fetchatt(att[attnum],
(char *) tup + tup->t_hoff +
att[attnum]->attcacheoff);
}
#endif
}
else
{
/*
* there's a null somewhere in the tuple
*
* check to see if desired att is null
*/
#ifdef IN_MACRO
/* This is handled in the macro */
if (att_isnull(attnum, bp))
{
if (isnull)
*isnull = true;
return (Datum) NULL;
}
#endif
/*
* Now check to see if any preceding bits are null...
*/
{
int byte = attnum >> 3;
int finalbit = attnum & 0x07;
/* check for nulls "before" final bit of last byte */
if ((~bp[byte]) & ((1 << finalbit) - 1))
slow = true;
else
{
/* check for nulls in any "earlier" bytes */
int i;
for (i = 0; i < byte; i++)
{
if (bp[i] != 0xFF)
{
slow = true;
break;
}
}
}
}
}
tp = (char *) tup + tup->t_hoff;
/*
* now check for any non-fixed length attrs before our attribute
*/
if (!slow)
{
/*
* If we get here, there are no nulls up to and including the target
* attribute. If we have a cached offset, we can use it.
*/
if (att[attnum]->attcacheoff >= 0)
{
return fetchatt(att[attnum],
tp + att[attnum]->attcacheoff);
}
/*
* Otherwise, check for non-fixed-length attrs up to and including
* target. If there aren't any, it's safe to cheaply initialize the
* cached offsets for these attrs.
*/
if (HeapTupleHasVarWidth(tuple))
{
int j;
/*
* In for(), we test <= and not < because we want to see if we can
* go past it in initializing offsets.
*/
for (j = 0; j <= attnum; j++)
{
if (att[j]->attlen <= 0)
{
slow = true;
break;
}
}
}
}
/*
* If slow is false, and we got here, we know that we have a tuple with no
* nulls or var-widths before the target attribute. If possible, we also
* want to initialize the remainder of the attribute cached offset values.
*/
if (!slow)
{
int j = 1;
long off;
int natts = HeapTupleHeaderGetNatts(tup);
/*
* If we get here, we have a tuple with no nulls or var-widths up to
* and including the target attribute, so we can use the cached offset
* ... only we don't have it yet, or we'd not have got here. Since
* it's cheap to compute offsets for fixed-width columns, we take the
* opportunity to initialize the cached offsets for *all* the leading
* fixed-width columns, in hope of avoiding future visits to this
* routine.
*/
/* this is always true */
att[0]->attcacheoff = 0;
while (j < attnum && att[j]->attcacheoff > 0)
j++;
off = att[j - 1]->attcacheoff + att[j - 1]->attlen;
for (; j <= attnum ||
/* Can we compute more? We will probably need them */
(j < natts &&
att[j]->attcacheoff == -1 &&
(HeapTupleNoNulls(tuple) || !att_isnull(j, bp)) &&
(HeapTupleAllFixed(tuple) || att[j]->attlen > 0)); j++)
{
/* don't need to worry about shortvarlenas here since we're only
* looking at non-varlenas. Note that it's important that we check
* that the target attribute itself is a nonvarlena too since we
* can't use cached offsets for even the first varlena any more. */
off = att_align(off, att[j]->attalign);
att[j]->attcacheoff = off;
off = att_addlength(off, att[j]->attlen, PointerGetDatum(tp + off));
}
return fetchatt(att[attnum], tp + att[attnum]->attcacheoff);
}
else
{
bool usecache = true;
int off = 0;
int i;
/* this is always true */
att[0]->attcacheoff = 0;
/*
* Now we know that we have to walk the tuple CAREFULLY.
*
* Note - This loop is a little tricky. For each non-null attribute,
* we have to first account for alignment padding before the attr,
* then advance over the attr based on its length. Nulls have no
* storage and no alignment padding either. We can use/set
* attcacheoff until we reach either a null or a var-width attribute.
*/
for (i = 0; i < attnum; i++)
{
if (HeapTupleHasNulls(tuple) && att_isnull(i, bp))
{
usecache = false;
continue;
}
/* If we know the next offset, we can skip the alignment calc */
if (usecache && att[i]->attcacheoff != -1)
off = att[i]->attcacheoff;
else
{
/* if it's a varlena it may or may not be aligned, so check for
* something that looks like a padding byte before aligning. If
* we're already aligned it may be the leading byte of a 4-byte
* header but then the att_align is harmless. Don't bother
* looking if it's not a varlena though.*/
if (att[i]->attlen != -1 || !tp[off])
off = att_align(off, att[i]->attalign);
if (usecache && att[i]->attlen != -1)
att[i]->attcacheoff = off;
}
if (att[i]->attlen < 0)
usecache = false;
off = att_addlength(off, att[i]->attlen, PointerGetDatum(tp + off));
}
if (att[attnum]->attlen != -1 || !tp[off])
off = att_align(off, att[attnum]->attalign);
return fetchatt(att[attnum], tp + off);
}
}
/*
* slot_deform_tuple
* Given a TupleTableSlot, extract data from the slot's physical tuple
* into its Datum/isnull arrays. Data is extracted up through the
* natts'th column (caller must ensure this is a legal column number).
*
* This is essentially an incremental version of heap_deform_tuple:
* on each call we extract attributes up to the one needed, without
* re-computing information about previously extracted attributes.
* slot->tts_nvalid is the number of attributes already extracted.
*/
static void
slot_deform_tuple(TupleTableSlot *slot, int natts)
{
HeapTuple tuple = TupGetHeapTuple(slot);
TupleDesc tupleDesc = slot->tts_tupleDescriptor;
Datum *values = slot->PRIVATE_tts_values;
bool *isnull = slot->PRIVATE_tts_isnull;
HeapTupleHeader tup = tuple->t_data;
bool hasnulls = HeapTupleHasNulls(tuple);
Form_pg_attribute *att = tupleDesc->attrs;
int attnum;
char *tp; /* ptr to tuple data */
long off; /* offset in tuple data */
bits8 *bp = tup->t_bits; /* ptr to null bitmap in tuple */
bool slow; /* can we use/set attcacheoff? */
/*
* Check whether the first call for this tuple, and initialize or restore
* loop state.
*/
attnum = slot->PRIVATE_tts_nvalid;
if (attnum == 0)
{
/* Start from the first attribute */
off = 0;
slow = false;
}
else
{
/* Restore state from previous execution */
off = slot->PRIVATE_tts_off;
slow = slot->PRIVATE_tts_slow;
}
tp = (char *) tup + tup->t_hoff;
for (; attnum < natts; attnum++)
{
Form_pg_attribute thisatt = att[attnum];
if (hasnulls && att_isnull(attnum, bp))
{
values[attnum] = (Datum) 0;
isnull[attnum] = true;
slow = true; /* can't use attcacheoff anymore */
continue;
}
isnull[attnum] = false;
if (!slow && thisatt->attcacheoff >= 0)
off = thisatt->attcacheoff;
else
{
/* if it's a varlena it may or may not be aligned, so check for
* something that looks like a padding byte before aligning. If
* we're already aligned it may be the leading byte of a 4-byte
* header but then the att_align is harmless. Don't bother looking
* if it's not a varlena though.*/
if (thisatt->attlen != -1 || !tp[off])
off = att_align(off, thisatt->attalign);
if (!slow && thisatt->attlen != -1)
thisatt->attcacheoff = off;
}
if (!slow && thisatt->attlen < 0)
slow = true;
values[attnum] = fetchatt(thisatt, tp + off);
off = att_addlength(off, thisatt->attlen, PointerGetDatum(tp + off));
}
/*
* Save state for next execution
*/
slot->PRIVATE_tts_nvalid = attnum;
slot->PRIVATE_tts_off = off;
slot->PRIVATE_tts_slow = slow;
}