/*
* 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 = diskdsc->attrs[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);
}
}
}
/* ----------------
* 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)
{
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)
{
Form_pg_attribute att;
/*
* 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.
*/
att = TupleDescAttr(tupleDesc, attnum);
if (att->attcacheoff >= 0)
return fetchatt(att, tp + att->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 (TupleDescAttr(tupleDesc, 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.
*/
TupleDescAttr(tupleDesc, 0)->attcacheoff = 0;
/* we might have set some offsets in the slow path previously */
while (j < natts && TupleDescAttr(tupleDesc, j)->attcacheoff > 0)
j++;
off = TupleDescAttr(tupleDesc, j - 1)->attcacheoff +
TupleDescAttr(tupleDesc, j - 1)->attlen;
for (; j < natts; j++)
{
Form_pg_attribute att = TupleDescAttr(tupleDesc, j);
if (att->attlen <= 0)
break;
off = att_align_nominal(off, att->attalign);
att->attcacheoff = off;
off += att->attlen;
}
Assert(j > attnum);
off = TupleDescAttr(tupleDesc, 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" */
{
Form_pg_attribute att = TupleDescAttr(tupleDesc, i);
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->attcacheoff >= 0)
off = att->attcacheoff;
else if (att->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->attalign))
att->attcacheoff = off;
else
{
off = att_align_pointer(off, att->attalign, -1,
tp + off);
usecache = false;
}
}
else
{
/* not varlena, so safe to use att_align_nominal */
off = att_align_nominal(off, att->attalign);
if (usecache)
att->attcacheoff = off;
}
if (i == attnum)
break;
off = att_addlength_pointer(off, att->attlen, tp + off);
if (usecache && att->attlen <= 0)
usecache = false;
}
}
return fetchatt(TupleDescAttr(tupleDesc, attnum), tp + off);
}
static void
convert_heaptuple(HeapTupleHeader htup)
{
/* HEAP_HASEXTENDED and HEAP_HASCOMPRESSED flags were removed. Clear them out */
htup->t_infomask &= ~(VERSION4_HEAP_HASEXTENDED | VERSION4_HEAP_HASCOMPRESSED);
/* HEAP_HASOID flag was moved */
if (htup->t_infomask & VERSION4_HEAP_HASOID)
{
htup->t_infomask &= ~(VERSION4_HEAP_HASOID);
htup->t_infomask |= HEAP_HASOID;
}
/* Any numeric columns? */
if (curr_hasnumerics)
{
/* This is like heap_deform_tuple() */
bool hasnulls = (htup->t_infomask & HEAP_HASNULL) != 0;
int attnum;
char *tp;
long off;
bits8 *bp = htup->t_bits; /* ptr to null bitmap in tuple */
tp = (char *) htup + htup->t_hoff;
off = 0;
for (attnum = 0; attnum < curr_natts; attnum++)
{
AttInfo *thisatt = &curr_atts[attnum];
if (hasnulls && att_isnull(attnum, bp))
continue;
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);
}
if (thisatt->is_numeric)
{
/*
* Before PostgreSQL 8.3, the n_weight and n_sign_dscale fields
* were the other way 'round. Swap them.
*
* FIXME: need to handle toasted datums here.
*/
Datum datum = PointerGetDatum(tp + off);
if (VARATT_IS_COMPRESSED(datum))
pg_log(PG_FATAL, "converting compressed numeric datums is not implemented\n");
else if (VARATT_IS_EXTERNAL(datum))
pg_log(PG_FATAL, "converting toasted numeric datums is not implemented\n");
else
{
char *numericdata = VARDATA_ANY(DatumGetPointer(datum));
int sz = VARSIZE_ANY_EXHDR(DatumGetPointer(datum));
uint16 tmp;
if (sz < 4)
pg_log(PG_FATAL, "unexpected size for numeric datum: %d\n", sz);
memcpy(&tmp, &numericdata[0], 2);
memcpy(&numericdata[0], &numericdata[2], 2);
memcpy(&numericdata[2], &tmp, 2);
}
}
off = att_addlength_pointer(off, thisatt->attlen, 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;
}
/*
* 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;
}
}
/* checks the individual attributes of the tuple */
uint32 check_index_tuple_attributes(Relation rel, PageHeader header, int block, int i, char *buffer) {
IndexTuple tuple;
uint32 nerrs = 0;
int j, off;
bits8 * bitmap;
BTPageOpaque opaque;
ereport(DEBUG2,(errmsg("[%d:%d] checking attributes for the tuple", block, i)));
/* get the index tuple and info about the page */
tuple = (IndexTuple)(buffer + header->pd_linp[i].lp_off);
opaque = (BTPageOpaque)(buffer + header->pd_special);
/* current attribute offset - always starts at (buffer + off) */
off = header->pd_linp[i].lp_off + IndexInfoFindDataOffset(tuple->t_info);
ereport(DEBUG3,(errmsg("[%d:%d] tuple has %d attributes", block, (i+1),
RelationGetNumberOfAttributes(rel))));
bitmap = (bits8*)(buffer + header->pd_linp[i].lp_off + sizeof(IndexTupleData));
/* TODO This is mostly copy'n'paste from check_heap_tuple_attributes,
so maybe it could be refactored to share the code. */
/* For left-most tuples on non-leaf pages, there are no data actually
(see src/backend/access/nbtree/README, last paragraph in section "Notes
About Data Representation")
Use P_LEFTMOST/P_ISLEAF to identify such cases (for the leftmost item only)
and set len = 0.
*/
if (P_LEFTMOST(opaque) && (! P_ISLEAF(opaque)) && (i == 0)) {
ereport(DEBUG3, (errmsg("[%d:%d] leftmost tuple on non-leaf block => no data, skipping", block, i)));
return nerrs;
}
/* check all the index attributes */
for (j = 0; j < rel->rd_att->natts; j++) {
/* default length of the attribute */
int len = rel->rd_att->attrs[j]->attlen;
/* copy from src/backend/commands/analyze.c */
bool is_varlena = (!rel->rd_att->attrs[j]->attbyval && len == -1);
bool is_varwidth = (!rel->rd_att->attrs[j]->attbyval && len < 0); /* thus it's "len = -2" */
/* if the attribute is marked as NULL (in the tuple header), skip to the next attribute */
if (IndexTupleHasNulls(tuple) && att_isnull(j, bitmap)) {
ereport(DEBUG3, (errmsg("[%d:%d] attribute '%s' is NULL (skipping)", block, (i+1), rel->rd_att->attrs[j]->attname.data)));
continue;
}
/* fix the alignment (see src/include/access/tupmacs.h) */
off = att_align_pointer(off, rel->rd_att->attrs[j]->attalign, rel->rd_att->attrs[j]->attlen, buffer+off);
if (is_varlena) {
/*
other interesting macros (see postgres.h) - should do something about those ...
VARATT_IS_COMPRESSED(PTR) VARATT_IS_4B_C(PTR)
VARATT_IS_EXTERNAL(PTR) VARATT_IS_1B_E(PTR)
VARATT_IS_SHORT(PTR) VARATT_IS_1B(PTR)
VARATT_IS_EXTENDED(PTR) (!VARATT_IS_4B_U(PTR))
*/
len = VARSIZE_ANY(buffer + off);
if (len < 0) {
ereport(WARNING, (errmsg("[%d:%d] attribute '%s' has negative length < 0 (%d)", block, (i+1), rel->rd_att->attrs[j]->attname.data, len)));
++nerrs;
break;
}
if (VARATT_IS_COMPRESSED(buffer + off)) {
/* the raw length should be less than 1G (and positive) */
if ((VARRAWSIZE_4B_C(buffer + off) < 0) || (VARRAWSIZE_4B_C(buffer + off) > 1024*1024)) {
ereport(WARNING, (errmsg("[%d:%d] attribute '%s' has invalid length %d (should be between 0 and 1G)", block, (i+1), rel->rd_att->attrs[j]->attname.data, VARRAWSIZE_4B_C(buffer + off))));
++nerrs;
/* no break here, this does not break the page structure - we may check the other attributes */
}
}
/* FIXME Check if the varlena value may be detoasted. */
} else if (is_varwidth) {
/* get the C-string length (at most to the end of tuple), +1 as it does not include '\0' at the end */
/* if the string is not properly terminated, then this returns 'remaining space + 1' so it's detected */
len = strnlen(buffer + off, header->pd_linp[i].lp_off + len + header->pd_linp[i].lp_len - off) + 1;
}
/* Check if the length makes sense (is not negative and does not overflow
* the tuple end, stop validating the other rows (we don't know where to
* continue anyway). */
if (off + len > (header->pd_linp[i].lp_off + header->pd_linp[i].lp_len)) {
ereport(WARNING, (errmsg("[%d:%d] attribute '%s' (off=%d len=%d) overflows tuple end (off=%d, len=%d)", block, (i+1), rel->rd_att->attrs[j]->attname.data, off, len, header->pd_linp[i].lp_off, header->pd_linp[i].lp_len)));
++nerrs;
break;
}
/* skip to the next attribute */
off += len;
ereport(DEBUG3,(errmsg("[%d:%d] attribute '%s' len=%d", block, (i+1), rel->rd_att->attrs[j]->attname.data, len)));
}
ereport(DEBUG3,(errmsg("[%d:%d] last attribute ends at %d, tuple ends at %d", block, (i+1), off, header->pd_linp[i].lp_off + header->pd_linp[i].lp_len)));
/* after the last attribute, the offset should be exactly the same as the end of the tuple */
if (MAXALIGN(off) != header->pd_linp[i].lp_off + header->pd_linp[i].lp_len) {
ereport(WARNING, (errmsg("[%d:%d] the last attribute ends at %d but the tuple ends at %d", block, (i+1), off, header->pd_linp[i].lp_off + header->pd_linp[i].lp_len)));
++nerrs;
}
return nerrs;
}
/*
* tuple_data_split_internal
*
* Split raw tuple data taken directly from a page into an array of bytea
* elements. This routine does a lookup on NULL values and creates array
* elements accordingly. This is a reimplementation of nocachegetattr()
* in heaptuple.c simplified for educational purposes.
*/
static Datum
tuple_data_split_internal(Oid relid, char *tupdata,
uint16 tupdata_len, uint16 t_infomask,
uint16 t_infomask2, bits8 *t_bits,
bool do_detoast)
{
ArrayBuildState *raw_attrs;
int nattrs;
int i;
int off = 0;
Relation rel;
TupleDesc tupdesc;
/* Get tuple descriptor from relation OID */
rel = relation_open(relid, NoLock);
tupdesc = CreateTupleDescCopyConstr(rel->rd_att);
relation_close(rel, NoLock);
raw_attrs = initArrayResult(BYTEAOID, CurrentMemoryContext, false);
nattrs = tupdesc->natts;
if (nattrs < (t_infomask2 & HEAP_NATTS_MASK))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("number of attributes in tuple header is greater than number of attributes in tuple descriptor")));
for (i = 0; i < nattrs; i++)
{
Form_pg_attribute attr;
bool is_null;
bytea *attr_data = NULL;
attr = tupdesc->attrs[i];
is_null = (t_infomask & HEAP_HASNULL) && att_isnull(i, t_bits);
/*
* Tuple header can specify less attributes than tuple descriptor as
* ALTER TABLE ADD COLUMN without DEFAULT keyword does not actually
* change tuples in pages, so attributes with numbers greater than
* (t_infomask2 & HEAP_NATTS_MASK) should be treated as NULL.
*/
if (i >= (t_infomask2 & HEAP_NATTS_MASK))
is_null = true;
if (!is_null)
{
int len;
if (attr->attlen == -1)
{
off = att_align_pointer(off, tupdesc->attrs[i]->attalign, -1,
tupdata + off);
/*
* As VARSIZE_ANY throws an exception if it can't properly
* detect the type of external storage in macros VARTAG_SIZE,
* this check is repeated to have a nicer error handling.
*/
if (VARATT_IS_EXTERNAL(tupdata + off) &&
!VARATT_IS_EXTERNAL_ONDISK(tupdata + off) &&
!VARATT_IS_EXTERNAL_INDIRECT(tupdata + off))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("first byte of varlena attribute is incorrect for attribute %d", i)));
len = VARSIZE_ANY(tupdata + off);
}
else
{
off = att_align_nominal(off, tupdesc->attrs[i]->attalign);
len = attr->attlen;
}
if (tupdata_len < off + len)
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("unexpected end of tuple data")));
if (attr->attlen == -1 && do_detoast)
attr_data = DatumGetByteaPCopy(tupdata + off);
else
{
attr_data = (bytea *) palloc(len + VARHDRSZ);
SET_VARSIZE(attr_data, len + VARHDRSZ);
memcpy(VARDATA(attr_data), tupdata + off, len);
}
off = att_addlength_pointer(off, tupdesc->attrs[i]->attlen,
tupdata + off);
}
raw_attrs = accumArrayResult(raw_attrs, PointerGetDatum(attr_data),
is_null, BYTEAOID, CurrentMemoryContext);
if (attr_data)
pfree(attr_data);
}
if (tupdata_len != off)
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("end of tuple reached without looking at all its data")));
return makeArrayResult(raw_attrs, CurrentMemoryContext);
}
