/* ----------
* heap_tuple_untoast_attr_slice -
*
* Public entry point to get back part of a toasted value
* from compression or external storage.
* ----------
*/
varattrib *
heap_tuple_untoast_attr_slice(varattrib *attr, int32 sliceoffset, int32 slicelength)
{
varattrib *preslice;
varattrib *result;
int32 attrsize;
if (VARATT_IS_COMPRESSED(attr))
{
varattrib *tmp;
if (VARATT_IS_EXTERNAL(attr))
tmp = toast_fetch_datum(attr);
else
{
tmp = attr; /* compressed in main tuple */
}
preslice = (varattrib *) palloc(attr->va_content.va_external.va_rawsize
+ VARHDRSZ);
VARATT_SIZEP(preslice) = attr->va_content.va_external.va_rawsize + VARHDRSZ;
pglz_decompress((PGLZ_Header *) tmp, VARATT_DATA(preslice));
if (tmp != attr)
pfree(tmp);
}
else
{
/* Plain value */
if (VARATT_IS_EXTERNAL(attr))
{
/* fast path */
return (toast_fetch_datum_slice(attr, sliceoffset, slicelength));
}
else
preslice = attr;
}
/* slicing of datum for compressed cases and plain value */
attrsize = VARSIZE(preslice) - VARHDRSZ;
if (sliceoffset >= attrsize)
{
sliceoffset = 0;
slicelength = 0;
}
if (((sliceoffset + slicelength) > attrsize) || slicelength < 0)
slicelength = attrsize - sliceoffset;
result = (varattrib *) palloc(slicelength + VARHDRSZ);
VARATT_SIZEP(result) = slicelength + VARHDRSZ;
memcpy(VARDATA(result), VARDATA(preslice) + sliceoffset, slicelength);
if (preslice != attr)
pfree(preslice);
return result;
}
/* ----------
* toast_raw_datum_size -
*
* Return the raw (detoasted) size of a varlena datum
* (including the VARHDRSZ header)
* ----------
*/
Size
toast_raw_datum_size(Datum value)
{
varattrib *attr = (varattrib *) DatumGetPointer(value);
Size result;
if (VARATT_IS_EXTERNAL(attr))
{
/* va_rawsize is the size of the original datum -- including header */
result = attr->va_external.va_rawsize;
}
else if (VARATT_IS_COMPRESSED(attr))
{
/* here, va_rawsize is just the payload size */
result = attr->va_compressed.va_rawsize + VARHDRSZ;
}
else if (VARATT_IS_SHORT(attr))
{
/*
* we have to normalize the header length to VARHDRSZ or else the
* callers of this function will be confused.
*/
result = VARSIZE_SHORT(attr) - VARHDRSZ_SHORT + VARHDRSZ;
}
else
{
/* plain untoasted datum */
result = VARSIZE(attr);
}
return result;
}
/* ----------
* toast_datum_size
*
* Return the physical storage size (possibly compressed) of a varlena datum
* ----------
*/
Size
toast_datum_size(Datum value)
{
varattrib *attr = (varattrib *) DatumGetPointer(value);
Size result;
if (VARATT_IS_EXTERNAL(attr))
{
/*
* Attribute is stored externally - return the extsize whether
* compressed or not. We do not count the size of the toast pointer
* ... should we?
*/
result = attr->va_content.va_external.va_extsize;
}
else
{
/*
* Attribute is stored inline either compressed or not, just calculate
* the size of the datum in either case.
*/
result = VARSIZE(attr);
}
return result;
}
/* ----------
* toast_delete -
*
* Cascaded delete toast-entries on DELETE
* ----------
*/
static void
toast_delete(Relation rel, HeapTuple oldtup)
{
TupleDesc tupleDesc;
Form_pg_attribute *att;
int numAttrs;
int i;
Datum value;
bool isnull;
/*
* Get the tuple descriptor, the number of and attribute descriptors.
*/
tupleDesc = rel->rd_att;
numAttrs = tupleDesc->natts;
att = tupleDesc->attrs;
/*
* Check for external stored attributes and delete them from the
* secondary relation.
*/
for (i = 0; i < numAttrs; i++)
{
if (att[i]->attlen == -1)
{
value = heap_getattr(oldtup, i + 1, tupleDesc, &isnull);
if (!isnull && VARATT_IS_EXTERNAL(value))
toast_delete_datum(rel, value);
}
}
}
/* ----------
* toast_raw_datum_size -
*
* Return the raw (detoasted) size of a varlena datum
* (including the VARHDRSZ header)
* ----------
*/
Size
toast_raw_datum_size(Datum value)
{
struct varlena *attr = (struct varlena *) DatumGetPointer(value);
Size result;
if (VARATT_IS_EXTERNAL(attr))
{
/* va_rawsize is the size of the original datum -- including header */
struct varatt_external toast_pointer;
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
result = toast_pointer.va_rawsize;
}
else if (VARATT_IS_COMPRESSED(attr))
{
/* here, va_rawsize is just the payload size */
result = VARRAWSIZE_4B_C(attr) + VARHDRSZ;
}
else if (VARATT_IS_SHORT(attr))
{
/*
* we have to normalize the header length to VARHDRSZ or else the
* callers of this function will be confused.
*/
result = VARSIZE_SHORT(attr) - VARHDRSZ_SHORT + VARHDRSZ;
}
else
{
/* plain untoasted datum */
result = VARSIZE(attr);
}
return result;
}
/* ----------
* toast_compress_datum -
*
* Create a compressed version of a varlena datum
*
* If we fail (ie, compressed result is actually bigger than original)
* then return NULL. We must not use compressed data if it'd expand
* the tuple!
*
* We use VAR{SIZE,DATA}_ANY so we can handle short varlenas here without
* copying them. But we can't handle external or compressed datums.
* ----------
*/
Datum
toast_compress_datum(Datum value)
{
varattrib *tmp;
int32 valsize = VARSIZE_ANY_EXHDR_D(value);
Assert(!VARATT_IS_EXTERNAL(DatumGetPointer(value)));
Assert(!VARATT_IS_COMPRESSED(DatumGetPointer(value)));
/*
* No point in wasting a palloc cycle if value size is out of the allowed
* range for compression
*/
if (valsize < PGLZ_strategy_default->min_input_size ||
valsize > PGLZ_strategy_default->max_input_size)
return PointerGetDatum(NULL);
tmp = (varattrib *) palloc(PGLZ_MAX_OUTPUT(valsize));
if (pglz_compress(VARDATA_ANY_D(value), valsize,
(PGLZ_Header *) tmp, PGLZ_strategy_default) &&
VARSIZE(tmp) < VARSIZE_ANY_D(value))
{
/* successful compression */
VARATT_SET_COMPRESSED(tmp);
return PointerGetDatum(tmp);
}
else
{
/* incompressible data */
pfree(tmp);
return PointerGetDatum(NULL);
}
}
/* ----------
* toast_datum_size
*
* Return the physical storage size (possibly compressed) of a varlena datum
* ----------
*/
Size
toast_datum_size(Datum value)
{
struct varlena *attr = (struct varlena *) DatumGetPointer(value);
Size result;
if (VARATT_IS_EXTERNAL(attr))
{
/*
* Attribute is stored externally - return the extsize whether
* compressed or not. We do not count the size of the toast pointer
* ... should we?
*/
struct varatt_external toast_pointer;
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
result = toast_pointer.va_extsize;
}
else if (VARATT_IS_SHORT(attr))
{
result = VARSIZE_SHORT(attr);
}
else
{
/*
* Attribute is stored inline either compressed or not, just calculate
* the size of the datum in either case.
*/
result = VARSIZE(attr);
}
return result;
}
/* ----------
* toast_raw_datum_size -
*
* Return the raw (detoasted) size of a varlena datum
* ----------
*/
Size
toast_raw_datum_size(Datum value)
{
varattrib *attr = (varattrib *) DatumGetPointer(value);
Size result;
if (VARATT_IS_COMPRESSED(attr))
{
/*
* va_rawsize shows the original data size, whether the datum is
* external or not.
*/
result = attr->va_content.va_compressed.va_rawsize + VARHDRSZ;
}
else if (VARATT_IS_EXTERNAL(attr))
{
/*
* an uncompressed external attribute has rawsize including the
* header (not too consistent!)
*/
result = attr->va_content.va_external.va_rawsize;
}
else
{
/* plain untoasted datum */
result = VARSIZE(attr);
}
return result;
}
/**
* If this function is changed then update varattrib_untoast_len as well
*/
void varattrib_untoast_ptr_len(Datum d, char **datastart, int *len, void **tofree)
{
if (DatumGetPointer(d) == NULL)
{
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg(" Unable to detoast datum "),
errprintstack(true)));
}
struct varlena *va = (struct varlena *) DatumGetPointer(d);
varattrib *attr = (varattrib *) va;
*len = -1;
*tofree = NULL;
if(VARATT_IS_EXTENDED(attr))
{
if(VARATT_IS_EXTERNAL(attr))
{
attr = (varattrib *)toast_fetch_datum((struct varlena *)attr);
/* toast_fetch_datum will palloc, so set it up for free */
*tofree = attr;
}
if(VARATT_IS_COMPRESSED(attr))
{
PGLZ_Header *tmp = (PGLZ_Header *) attr;
attr = (varattrib *) palloc(PGLZ_RAW_SIZE(tmp) + VARHDRSZ);
SET_VARSIZE(attr, PGLZ_RAW_SIZE(tmp) + VARHDRSZ);
pglz_decompress(tmp, VARDATA(attr));
/* If tofree is set, that is, we get it from toast_fetch_datum.
* We need to free it here
*/
if(*tofree)
pfree(*tofree);
*tofree = attr;
}
else if(VARATT_IS_SHORT(attr))
{
/* Warning! Return unaligned pointer! */
*len = VARSIZE_SHORT(attr) - VARHDRSZ_SHORT;
*datastart = VARDATA_SHORT(attr);
attr = NULL;
}
}
if(*len == -1)
{
*datastart = VARDATA(attr);
*len = VARSIZE(attr) - VARHDRSZ;
}
Assert(*len >= 0);
}
/*
* Receive a tuple from the executor and store it in the tuplestore.
* This is for the case where we have to detoast any toasted values.
*/
static void
tstoreReceiveSlot_detoast(TupleTableSlot *slot, DestReceiver *self)
{
TStoreState *myState = (TStoreState *) self;
TupleDesc typeinfo = slot->tts_tupleDescriptor;
Form_pg_attribute *attrs = typeinfo->attrs;
int natts = typeinfo->natts;
int nfree;
int i;
HeapTuple tuple;
MemoryContext oldcxt;
/* Make sure the tuple is fully deconstructed */
slot_getallattrs(slot);
/*
* Fetch back any out-of-line datums. We build the new datums array in
* myState->outvalues[] (but we can re-use the slot's isnull array).
* Also, remember the fetched values to free afterwards.
*/
nfree = 0;
for (i = 0; i < natts; i++)
{
Datum val = slot->tts_values[i];
if (!attrs[i]->attisdropped &&
attrs[i]->attlen == -1 &&
!slot->tts_isnull[i])
{
if (VARATT_IS_EXTERNAL(DatumGetPointer(val)))
{
val = PointerGetDatum(heap_tuple_fetch_attr((varattrib *)
DatumGetPointer(val)));
myState->tofree[nfree++] = val;
}
}
myState->outvalues[i] = val;
}
/*
* Push the modified tuple into the tuplestore.
*/
tuple = heap_form_tuple(typeinfo,
myState->outvalues, slot->tts_isnull);
oldcxt = MemoryContextSwitchTo(myState->cxt);
tuplestore_puttuple(myState->tstore, tuple);
MemoryContextSwitchTo(oldcxt);
heap_freetuple(tuple);
/* And release any temporary detoasted values */
for (i = 0; i < nfree; i++)
pfree(DatumGetPointer(myState->tofree[i]));
}
/* ----------
* heap_tuple_untoast_attr -
*
* Public entry point to get back a toasted value from compression
* or external storage.
* ----------
*/
varattrib *
heap_tuple_untoast_attr(varattrib *attr)
{
varattrib *result;
if (VARATT_IS_EXTERNAL(attr))
{
if (VARATT_IS_COMPRESSED(attr))
{
/* ----------
* This is an external stored compressed value
* Fetch it from the toast heap and decompress.
* ----------
*/
varattrib *tmp;
tmp = toast_fetch_datum(attr);
result = (varattrib *) palloc(attr->va_content.va_external.va_rawsize
+ VARHDRSZ);
VARATT_SIZEP(result) = attr->va_content.va_external.va_rawsize
+ VARHDRSZ;
pglz_decompress((PGLZ_Header *) tmp, VARATT_DATA(result));
pfree(tmp);
}
else
{
/*
* This is an external stored plain value
*/
result = toast_fetch_datum(attr);
}
}
else if (VARATT_IS_COMPRESSED(attr))
{
/*
* This is a compressed value inside of the main tuple
*/
result = (varattrib *) palloc(attr->va_content.va_compressed.va_rawsize
+ VARHDRSZ);
VARATT_SIZEP(result) = attr->va_content.va_compressed.va_rawsize
+ VARHDRSZ;
pglz_decompress((PGLZ_Header *) attr, VARATT_DATA(result));
}
else
/*
* This is a plain value inside of the main tuple - why am I
* called?
*/
return attr;
return result;
}
/* ----------
* toast_delete_datum -
*
* Delete a single external stored value.
* ----------
*/
static void
toast_delete_datum(Relation rel, Datum value)
{
struct varlena *attr = (struct varlena *) DatumGetPointer(value);
struct varatt_external toast_pointer;
Relation toastrel;
Relation toastidx;
ScanKeyData toastkey;
SysScanDesc toastscan;
HeapTuple toasttup;
if (!VARATT_IS_EXTERNAL(attr))
return;
/* Must copy to access aligned fields */
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
/*
* Open the toast relation and its index
*/
toastrel = heap_open(toast_pointer.va_toastrelid, RowExclusiveLock);
toastidx = index_open(toastrel->rd_rel->reltoastidxid, RowExclusiveLock);
/*
* Setup a scan key to find chunks with matching va_valueid
*/
ScanKeyInit(&toastkey,
(AttrNumber) 1,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(toast_pointer.va_valueid));
/*
* Find all the chunks. (We don't actually care whether we see them in
* sequence or not, but since we've already locked the index we might as
* well use systable_beginscan_ordered.)
*/
toastscan = systable_beginscan_ordered(toastrel, toastidx,
SnapshotToast, 1, &toastkey);
while ((toasttup = systable_getnext_ordered(toastscan, ForwardScanDirection)) != NULL)
{
/*
* Have a chunk, delete it
*/
simple_heap_delete(toastrel, &toasttup->t_self);
}
/*
* End scan and close relations
*/
systable_endscan_ordered(toastscan);
index_close(toastidx, RowExclusiveLock);
heap_close(toastrel, RowExclusiveLock);
}
/* ----------
* toast_delete_datum -
*
* Delete a single external stored value.
* ----------
*/
static void
toast_delete_datum(Relation rel __attribute__((unused)), Datum value)
{
varattrib *attr = (varattrib *) DatumGetPointer(value);
Relation toastrel;
Relation toastidx;
ScanKeyData toastkey;
IndexScanDesc toastscan;
HeapTuple toasttup;
if (!VARATT_IS_EXTERNAL(attr))
return;
/*
* Open the toast relation and its index
*/
toastrel = heap_open(attr->va_external.va_toastrelid,
RowExclusiveLock);
toastidx = index_open(toastrel->rd_rel->reltoastidxid, RowExclusiveLock);
/*
* Setup a scan key to fetch from the index by va_valueid (we don't
* particularly care whether we see them in sequence or not)
*/
ScanKeyInit(&toastkey,
(AttrNumber) 1,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(attr->va_external.va_valueid));
/*
* Find all the chunks. (We don't actually care whether we see them in
* sequence or not, but since we've already locked the index we might as
* well use systable_beginscan_ordered.)
*/
toastscan = index_beginscan(toastrel, toastidx,
SnapshotToast, 1, &toastkey);
while ((toasttup = index_getnext(toastscan, ForwardScanDirection)) != NULL)
{
/*
* Have a chunk, delete it
*/
simple_heap_delete(toastrel, &toasttup->t_self);
}
/*
* End scan and close relations
*/
index_endscan(toastscan);
index_close(toastidx, RowExclusiveLock);
heap_close(toastrel, RowExclusiveLock);
}
/* ----------
* toast_delete_datum -
*
* Delete a single external stored value.
* ----------
*/
static void
toast_delete_datum(Relation rel, Datum value)
{
varattrib *attr = (varattrib *) DatumGetPointer(value);
Relation toastrel;
Relation toastidx;
ScanKeyData toastkey;
IndexScanDesc toastscan;
HeapTuple toasttup;
if (!VARATT_IS_EXTERNAL(attr))
return;
/*
* Open the toast relation and it's index
*/
toastrel = heap_open(attr->va_content.va_external.va_toastrelid,
RowExclusiveLock);
toastidx = index_open(toastrel->rd_rel->reltoastidxid);
/*
* Setup a scan key to fetch from the index by va_valueid (we don't
* particularly care whether we see them in sequence or not)
*/
ScanKeyEntryInitialize(&toastkey,
(bits16) 0,
(AttrNumber) 1,
(RegProcedure) F_OIDEQ,
ObjectIdGetDatum(attr->va_content.va_external.va_valueid));
/*
* Find the chunks by index
*/
toastscan = index_beginscan(toastrel, toastidx, SnapshotToast,
1, &toastkey);
while ((toasttup = index_getnext(toastscan, ForwardScanDirection)) != NULL)
{
/*
* Have a chunk, delete it
*/
simple_heap_delete(toastrel, &toasttup->t_self);
}
/*
* End scan and close relations
*/
index_endscan(toastscan);
index_close(toastidx);
heap_close(toastrel, RowExclusiveLock);
}
/* ----------
* toast_delete -
*
* Cascaded delete toast-entries on DELETE
* ----------
*/
void
toast_delete(Relation rel, HeapTuple oldtup)
{
TupleDesc tupleDesc;
Form_pg_attribute *att;
int numAttrs;
int i;
Datum toast_values[MaxHeapAttributeNumber];
bool toast_isnull[MaxHeapAttributeNumber];
/*
* We should only ever be called for tuples of plain relations ---
* recursing on a toast rel is bad news.
*/
Assert(rel->rd_rel->relkind == RELKIND_RELATION);
/*
* Get the tuple descriptor and break down the tuple into fields.
*
* NOTE: it's debatable whether to use heap_deform_tuple() here or just
* heap_getattr() only the varlena columns. The latter could win if there
* are few varlena columns and many non-varlena ones. However,
* heap_deform_tuple costs only O(N) while the heap_getattr way would cost
* O(N^2) if there are many varlena columns, so it seems better to err on
* the side of linear cost. (We won't even be here unless there's at
* least one varlena column, by the way.)
*/
tupleDesc = rel->rd_att;
att = tupleDesc->attrs;
numAttrs = tupleDesc->natts;
Assert(numAttrs <= MaxHeapAttributeNumber);
heap_deform_tuple(oldtup, tupleDesc, toast_values, toast_isnull);
/*
* Check for external stored attributes and delete them from the secondary
* relation.
*/
for (i = 0; i < numAttrs; i++)
{
if (att[i]->attlen == -1)
{
Datum value = toast_values[i];
if (!toast_isnull[i] && VARATT_IS_EXTERNAL(PointerGetDatum(value)))
toast_delete_datum(rel, value);
}
}
}
/*
* Extract data from the pg_statistic arrays into useful format.
*/
static Selectivity
mcelem_tsquery_selec(TSQuery query, Datum *mcelem, int nmcelem,
float4 *numbers, int nnumbers)
{
float4 minfreq;
TextFreq *lookup;
Selectivity selec;
int i;
/*
* There should be two more Numbers than Values, because the last two
* cells are taken for minimal and maximal frequency. Punt if not.
*
* (Note: the MCELEM statistics slot definition allows for a third extra
* number containing the frequency of nulls, but we're not expecting that
* to appear for a tsvector column.)
*/
if (nnumbers != nmcelem + 2)
return tsquery_opr_selec_no_stats(query);
/*
* Transpose the data into a single array so we can use bsearch().
*/
lookup = (TextFreq *) palloc(sizeof(TextFreq) * nmcelem);
for (i = 0; i < nmcelem; i++)
{
/*
* The text Datums came from an array, so it cannot be compressed or
* stored out-of-line -- it's safe to use VARSIZE_ANY*.
*/
Assert(!VARATT_IS_COMPRESSED(mcelem[i]) && !VARATT_IS_EXTERNAL(mcelem[i]));
lookup[i].element = (text *) DatumGetPointer(mcelem[i]);
lookup[i].frequency = numbers[i];
}
/*
* Grab the lowest frequency. compute_tsvector_stats() stored it for us in
* the one before the last cell of the Numbers array. See ts_typanalyze.c
*/
minfreq = numbers[nnumbers - 2];
selec = tsquery_opr_selec(GETQUERY(query), GETOPERAND(query), lookup,
nmcelem, minfreq);
pfree(lookup);
return selec;
}
/* ----------
* heap_tuple_untoast_attr -
*
* Public entry point to get back a toasted value from compression
* or external storage.
* ----------
*/
struct varlena *
heap_tuple_untoast_attr(struct varlena * attr)
{
if (VARATT_IS_EXTERNAL(attr))
{
/*
* This is an externally stored datum --- fetch it back from there
*/
attr = toast_fetch_datum(attr);
/* If it's compressed, decompress it */
if (VARATT_IS_COMPRESSED(attr))
{
PGLZ_Header *tmp = (PGLZ_Header *) attr;
attr = (struct varlena *) palloc(PGLZ_RAW_SIZE(tmp) + VARHDRSZ);
SET_VARSIZE(attr, PGLZ_RAW_SIZE(tmp) + VARHDRSZ);
pglz_decompress(tmp, VARDATA(attr));
pfree(tmp);
}
}
else if (VARATT_IS_COMPRESSED(attr))
{
/*
* This is a compressed value inside of the main tuple
*/
PGLZ_Header *tmp = (PGLZ_Header *) attr;
attr = (struct varlena *) palloc(PGLZ_RAW_SIZE(tmp) + VARHDRSZ);
SET_VARSIZE(attr, PGLZ_RAW_SIZE(tmp) + VARHDRSZ);
pglz_decompress(tmp, VARDATA(attr));
}
else if (VARATT_IS_SHORT(attr))
{
/*
* This is a short-header varlena --- convert to 4-byte header format
*/
Size data_size = VARSIZE_SHORT(attr) - VARHDRSZ_SHORT;
Size new_size = data_size + VARHDRSZ;
struct varlena *new_attr;
new_attr = (struct varlena *) palloc(new_size);
SET_VARSIZE(new_attr, new_size);
memcpy(VARDATA(new_attr), VARDATA_SHORT(attr), data_size);
attr = new_attr;
}
return attr;
}
/**
* If this function is changed then update varattrib_untoast_ptr_len as well
*/
int varattrib_untoast_len(Datum d)
{
if (DatumGetPointer(d) == NULL)
{
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg(" Unable to detoast datum "),
errprintstack(true)));
}
struct varlena *va = (struct varlena *) DatumGetPointer(d);
varattrib *attr = (varattrib *) va;
int len = -1;
void *toFree = NULL;
if(VARATT_IS_EXTENDED(attr))
{
if(VARATT_IS_EXTERNAL(attr))
{
attr = (varattrib *)toast_fetch_datum((struct varlena *)attr);
/* toast_fetch_datum will palloc, so set it up for free */
toFree = attr;
}
if(VARATT_IS_COMPRESSED(attr))
{
PGLZ_Header *tmp = (PGLZ_Header *) attr;
len = PGLZ_RAW_SIZE(tmp);
}
else if(VARATT_IS_SHORT(attr))
{
len = VARSIZE_SHORT(attr) - VARHDRSZ_SHORT;
}
}
if(len == -1)
{
len = VARSIZE(attr) - VARHDRSZ;
}
if ( toFree)
pfree(toFree);
Assert(len >= 0);
return len;
}
/* ----------
* toast_compress_datum -
*
* Create a compressed version of a varlena datum
*
* If we fail (ie, compressed result is actually bigger than original)
* then return NULL. We must not use compressed data if it'd expand
* the tuple!
*
* We use VAR{SIZE,DATA}_ANY so we can handle short varlenas here without
* copying them. But we can't handle external or compressed datums.
* ----------
*/
Datum
toast_compress_datum(Datum value)
{
struct varlena *tmp;
int32 valsize = VARSIZE_ANY_EXHDR(DatumGetPointer(value));
Assert(!VARATT_IS_EXTERNAL(DatumGetPointer(value)));
Assert(!VARATT_IS_COMPRESSED(DatumGetPointer(value)));
/*
* No point in wasting a palloc cycle if value size is out of the allowed
* range for compression
*/
if (valsize < PGLZ_strategy_default->min_input_size ||
valsize > PGLZ_strategy_default->max_input_size)
return PointerGetDatum(NULL);
tmp = (struct varlena *) palloc(PGLZ_MAX_OUTPUT(valsize));
/*
* We recheck the actual size even if pglz_compress() reports success,
* because it might be satisfied with having saved as little as one byte
* in the compressed data --- which could turn into a net loss once you
* consider header and alignment padding. Worst case, the compressed
* format might require three padding bytes (plus header, which is
* included in VARSIZE(tmp)), whereas the uncompressed format would take
* only one header byte and no padding if the value is short enough. So
* we insist on a savings of more than 2 bytes to ensure we have a gain.
*/
if (pglz_compress(VARDATA_ANY(DatumGetPointer(value)), valsize,
(PGLZ_Header *) tmp, PGLZ_strategy_default) &&
VARSIZE(tmp) < valsize - 2)
{
/* successful compression */
return PointerGetDatum(tmp);
}
else
{
/* incompressible data */
pfree(tmp);
return PointerGetDatum(NULL);
}
}
/* ----------
* heap_tuple_untoast_attr -
*
* Public entry point to get back a toasted value from compression
* or external storage.
* ----------
*/
struct varlena *
heap_tuple_untoast_attr(struct varlena *attr)
{
if (VARATT_IS_EXTERNAL(attr))
{
/*
* This is an externally stored datum --- fetch it back from there
*/
attr = toast_fetch_datum(attr);
/* fall through to IS_COMPRESSED if it's a compressed external datum */
}
if (VARATT_IS_COMPRESSED(attr))
{
/*
* This is a compressed value inside of the main tuple
*/
PGLZ_Header *tmp = (PGLZ_Header *) attr;
attr = (struct varlena *) palloc(PGLZ_RAW_SIZE(tmp) + VARHDRSZ);
SET_VARSIZE(attr, PGLZ_RAW_SIZE(tmp) + VARHDRSZ);
pglz_decompress(tmp, VARDATA(attr));
}
else if (VARATT_IS_SHORT(attr))
{
/*
* This is a short-header varlena --- convert to 4-byte header format
*/
Size data_size = VARSIZE_SHORT(attr);
Size new_size = data_size - VARHDRSZ_SHORT + VARHDRSZ;
varattrib *tmp = (varattrib *)attr;
/* This is a "short" varlena header but is otherwise a normal varlena */
attr = (struct varlena *) palloc(new_size);
SET_VARSIZE(attr, new_size);
memcpy(VARDATA(attr), VARDATA_SHORT(tmp), data_size - VARHDRSZ_SHORT);
}
return attr;
}
static void
datumstreamread_check_large_varlena_integrity(
DatumStreamRead * acc,
uint8 * buffer,
int32 contentLen)
{
struct varlena *va;
va = (struct varlena *) buffer;
if (contentLen < VARHDRSZ)
{
elog(ERROR, "Large varlena header too small. Found %d, expected at least %d",
contentLen,
VARHDRSZ);
}
if (VARATT_IS_EXTERNAL(va))
{
elog(ERROR, "Large varlena has a toast reference but Append-Only Column Store tables do not use toast");
}
}
/* ----------
* heap_tuple_fetch_attr -
*
* Public entry point to get back a toasted value from
* external storage (possibly still in compressed format).
*
* This will return a datum that contains all the data internally, ie, not
* relying on external storage, but it can still be compressed or have a short
* header.
----------
*/
struct varlena *
heap_tuple_fetch_attr(struct varlena * attr)
{
struct varlena *result;
if (VARATT_IS_EXTERNAL(attr))
{
/*
* This is an external stored plain value
*/
result = toast_fetch_datum(attr);
}
else
{
/*
* This is a plain value inside of the main tuple - why am I called?
*/
result = attr;
}
return result;
}
/* ----------
* toast_flatten_tuple_attribute -
*
* If a Datum is of composite type, "flatten" it to contain no toasted fields.
* This must be invoked on any potentially-composite field that is to be
* inserted into a tuple. Doing this preserves the invariant that toasting
* goes only one level deep in a tuple.
*
* Note that flattening does not mean expansion of short-header varlenas,
* so in one sense toasting is allowed within composite datums.
* ----------
*/
Datum
toast_flatten_tuple_attribute(Datum value,
Oid typeId, int32 typeMod)
{
TupleDesc tupleDesc;
HeapTupleHeader olddata;
HeapTupleHeader new_data;
int32 new_len;
int32 new_data_len;
HeapTupleData tmptup;
Form_pg_attribute *att;
int numAttrs;
int i;
bool need_change = false;
bool has_nulls = false;
Datum toast_values[MaxTupleAttributeNumber];
bool toast_isnull[MaxTupleAttributeNumber];
bool toast_free[MaxTupleAttributeNumber];
/*
* See if it's a composite type, and get the tupdesc if so.
*/
tupleDesc = lookup_rowtype_tupdesc_noerror(typeId, typeMod, true);
if (tupleDesc == NULL)
return value; /* not a composite type */
att = tupleDesc->attrs;
numAttrs = tupleDesc->natts;
/*
* Break down the tuple into fields.
*/
olddata = DatumGetHeapTupleHeader(value);
Assert(typeId == HeapTupleHeaderGetTypeId(olddata));
Assert(typeMod == HeapTupleHeaderGetTypMod(olddata));
/* Build a temporary HeapTuple control structure */
tmptup.t_len = HeapTupleHeaderGetDatumLength(olddata);
ItemPointerSetInvalid(&(tmptup.t_self));
tmptup.t_tableOid = InvalidOid;
tmptup.t_data = olddata;
Assert(numAttrs <= MaxTupleAttributeNumber);
heap_deform_tuple(&tmptup, tupleDesc, toast_values, toast_isnull);
memset(toast_free, 0, numAttrs * sizeof(bool));
for (i = 0; i < numAttrs; i++)
{
/*
* Look at non-null varlena attributes
*/
if (toast_isnull[i])
has_nulls = true;
else if (att[i]->attlen == -1)
{
struct varlena *new_value;
new_value = (struct varlena *) DatumGetPointer(toast_values[i]);
if (VARATT_IS_EXTERNAL(new_value) ||
VARATT_IS_COMPRESSED(new_value))
{
new_value = heap_tuple_untoast_attr(new_value);
toast_values[i] = PointerGetDatum(new_value);
toast_free[i] = true;
need_change = true;
}
}
}
/*
* If nothing to untoast, just return the original tuple.
*/
if (!need_change)
{
ReleaseTupleDesc(tupleDesc);
return value;
}
/*
* Calculate the new size of the tuple. Header size should not change,
* but data size might.
*/
new_len = offsetof(HeapTupleHeaderData, t_bits);
if (has_nulls)
new_len += BITMAPLEN(numAttrs);
if (olddata->t_infomask & HEAP_HASOID)
new_len += sizeof(Oid);
new_len = MAXALIGN(new_len);
Assert(new_len == olddata->t_hoff);
new_data_len = heap_compute_data_size(tupleDesc,
toast_values, toast_isnull);
new_len += new_data_len;
new_data = (HeapTupleHeader) palloc0(new_len);
/*
* Put the tuple header and the changed values into place
*/
memcpy(new_data, olddata, olddata->t_hoff);
HeapTupleHeaderSetDatumLength(new_data, new_len);
heap_fill_tuple(tupleDesc,
toast_values,
toast_isnull,
(char *) new_data + olddata->t_hoff,
new_data_len,
&(new_data->t_infomask),
has_nulls ? new_data->t_bits : NULL);
/*
* Free allocated temp values
*/
for (i = 0; i < numAttrs; i++)
if (toast_free[i])
pfree(DatumGetPointer(toast_values[i]));
ReleaseTupleDesc(tupleDesc);
return PointerGetDatum(new_data);
}
/* ----------------
* index_form_tuple
*
* This shouldn't leak any memory; otherwise, callers such as
* tuplesort_putindextuplevalues() will be very unhappy.
* ----------------
*/
IndexTuple
index_form_tuple(TupleDesc tupleDescriptor,
Datum *values,
bool *isnull)
{
char *tp; /* tuple pointer */
IndexTuple tuple; /* return tuple */
Size size,
data_size,
hoff;
int i;
unsigned short infomask = 0;
bool hasnull = false;
uint16 tupmask = 0;
int numberOfAttributes = tupleDescriptor->natts;
#ifdef TOAST_INDEX_HACK
Datum untoasted_values[INDEX_MAX_KEYS];
bool untoasted_free[INDEX_MAX_KEYS];
#endif
if (numberOfAttributes > INDEX_MAX_KEYS)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("number of index columns (%d) exceeds limit (%d)",
numberOfAttributes, INDEX_MAX_KEYS)));
#ifdef TOAST_INDEX_HACK
for (i = 0; i < numberOfAttributes; i++)
{
Form_pg_attribute att = tupleDescriptor->attrs[i];
untoasted_values[i] = values[i];
untoasted_free[i] = false;
/* Do nothing if value is NULL or not of varlena type */
if (isnull[i] || att->attlen != -1)
continue;
/*
* If value is stored EXTERNAL, must fetch it so we are not depending
* on outside storage. This should be improved someday.
*/
if (VARATT_IS_EXTERNAL(DatumGetPointer(values[i])))
{
untoasted_values[i] =
PointerGetDatum(heap_tuple_fetch_attr((struct varlena *)
DatumGetPointer(values[i])));
untoasted_free[i] = true;
}
/*
* If value is above size target, and is of a compressible datatype,
* try to compress it in-line.
*/
if (!VARATT_IS_EXTENDED(DatumGetPointer(untoasted_values[i])) &&
VARSIZE(DatumGetPointer(untoasted_values[i])) > TOAST_INDEX_TARGET &&
(att->attstorage == 'x' || att->attstorage == 'm'))
{
Datum cvalue = toast_compress_datum(untoasted_values[i]);
if (DatumGetPointer(cvalue) != NULL)
{
/* successful compression */
if (untoasted_free[i])
pfree(DatumGetPointer(untoasted_values[i]));
untoasted_values[i] = cvalue;
untoasted_free[i] = true;
}
}
}
#endif
for (i = 0; i < numberOfAttributes; i++)
{
if (isnull[i])
{
hasnull = true;
break;
}
}
if (hasnull)
infomask |= INDEX_NULL_MASK;
hoff = IndexInfoFindDataOffset(infomask);
#ifdef TOAST_INDEX_HACK
data_size = heap_compute_data_size(tupleDescriptor,
untoasted_values, isnull);
#else
data_size = heap_compute_data_size(tupleDescriptor,
values, isnull);
#endif
size = hoff + data_size;
size = MAXALIGN(size); /* be conservative */
tp = (char *) palloc0(size);
tuple = (IndexTuple) tp;
heap_fill_tuple(tupleDescriptor,
#ifdef TOAST_INDEX_HACK
untoasted_values,
#else
values,
#endif
isnull,
(char *) tp + hoff,
data_size,
&tupmask,
(hasnull ? (bits8 *) tp + sizeof(IndexTupleData) : NULL));
#ifdef TOAST_INDEX_HACK
for (i = 0; i < numberOfAttributes; i++)
{
if (untoasted_free[i])
pfree(DatumGetPointer(untoasted_values[i]));
}
#endif
/*
* We do this because heap_fill_tuple wants to initialize a "tupmask"
* which is used for HeapTuples, but we want an indextuple infomask. The
* only relevant info is the "has variable attributes" field. We have
* already set the hasnull bit above.
*/
if (tupmask & HEAP_HASVARWIDTH)
infomask |= INDEX_VAR_MASK;
/* Also assert we got rid of external attributes */
#ifdef TOAST_INDEX_HACK
Assert((tupmask & HEAP_HASEXTERNAL) == 0);
#endif
/*
* Here we make sure that the size will fit in the field reserved for it
* in t_info.
*/
if ((size & INDEX_SIZE_MASK) != size)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("index row requires %zu bytes, maximum size is %zu",
size, (Size) INDEX_SIZE_MASK)));
infomask |= size;
/*
* initialize metadata
*/
tuple->t_info = infomask;
return tuple;
}
/* ----------
* toast_insert_or_update -
*
* Delete no-longer-used toast-entries and create new ones to
* make the new tuple fit on INSERT or UPDATE
*
* Inputs:
* newtup: the candidate new tuple to be inserted
* oldtup: the old row version for UPDATE, or NULL for INSERT
* options: options to be passed to heap_insert() for toast rows
* Result:
* either newtup if no toasting is needed, or a palloc'd modified tuple
* that is what should actually get stored
*
* NOTE: neither newtup nor oldtup will be modified. This is a change
* from the pre-8.1 API of this routine.
* ----------
*/
HeapTuple
toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup,
int options)
{
HeapTuple result_tuple;
TupleDesc tupleDesc;
Form_pg_attribute *att;
int numAttrs;
int i;
bool need_change = false;
bool need_free = false;
bool need_delold = false;
bool has_nulls = false;
Size maxDataLen;
Size hoff;
char toast_action[MaxHeapAttributeNumber];
bool toast_isnull[MaxHeapAttributeNumber];
bool toast_oldisnull[MaxHeapAttributeNumber];
Datum toast_values[MaxHeapAttributeNumber];
Datum toast_oldvalues[MaxHeapAttributeNumber];
int32 toast_sizes[MaxHeapAttributeNumber];
bool toast_free[MaxHeapAttributeNumber];
bool toast_delold[MaxHeapAttributeNumber];
/*
* We should only ever be called for tuples of plain relations ---
* recursing on a toast rel is bad news.
*/
Assert(rel->rd_rel->relkind == RELKIND_RELATION);
/*
* Get the tuple descriptor and break down the tuple(s) into fields.
*/
tupleDesc = rel->rd_att;
att = tupleDesc->attrs;
numAttrs = tupleDesc->natts;
Assert(numAttrs <= MaxHeapAttributeNumber);
heap_deform_tuple(newtup, tupleDesc, toast_values, toast_isnull);
if (oldtup != NULL)
heap_deform_tuple(oldtup, tupleDesc, toast_oldvalues, toast_oldisnull);
/* ----------
* Then collect information about the values given
*
* NOTE: toast_action[i] can have these values:
* ' ' default handling
* 'p' already processed --- don't touch it
* 'x' incompressible, but OK to move off
*
* NOTE: toast_sizes[i] is only made valid for varlena attributes with
* toast_action[i] different from 'p'.
* ----------
*/
memset(toast_action, ' ', numAttrs * sizeof(char));
memset(toast_free, 0, numAttrs * sizeof(bool));
memset(toast_delold, 0, numAttrs * sizeof(bool));
for (i = 0; i < numAttrs; i++)
{
struct varlena *old_value;
struct varlena *new_value;
if (oldtup != NULL)
{
/*
* For UPDATE get the old and new values of this attribute
*/
old_value = (struct varlena *) DatumGetPointer(toast_oldvalues[i]);
new_value = (struct varlena *) DatumGetPointer(toast_values[i]);
/*
* If the old value is an external stored one, check if it has
* changed so we have to delete it later.
*/
if (att[i]->attlen == -1 && !toast_oldisnull[i] &&
VARATT_IS_EXTERNAL(old_value))
{
if (toast_isnull[i] || !VARATT_IS_EXTERNAL(new_value) ||
memcmp((char *) old_value, (char *) new_value,
VARSIZE_EXTERNAL(old_value)) != 0)
{
/*
* The old external stored value isn't needed any more
* after the update
*/
toast_delold[i] = true;
need_delold = true;
}
else
{
/*
* This attribute isn't changed by this update so we reuse
* the original reference to the old value in the new
* tuple.
*/
toast_action[i] = 'p';
continue;
}
}
}
else
{
/*
* For INSERT simply get the new value
*/
new_value = (struct varlena *) DatumGetPointer(toast_values[i]);
}
/*
* Handle NULL attributes
*/
if (toast_isnull[i])
{
toast_action[i] = 'p';
has_nulls = true;
continue;
}
/*
* Now look at varlena attributes
*/
if (att[i]->attlen == -1)
{
/*
* If the table's attribute says PLAIN always, force it so.
*/
if (att[i]->attstorage == 'p')
toast_action[i] = 'p';
/*
* We took care of UPDATE above, so any external value we find
* still in the tuple must be someone else's we cannot reuse.
* Fetch it back (without decompression, unless we are forcing
* PLAIN storage). If necessary, we'll push it out as a new
* external value below.
*/
if (VARATT_IS_EXTERNAL(new_value))
{
if (att[i]->attstorage == 'p')
new_value = heap_tuple_untoast_attr(new_value);
else
new_value = heap_tuple_fetch_attr(new_value);
toast_values[i] = PointerGetDatum(new_value);
toast_free[i] = true;
need_change = true;
need_free = true;
}
/*
* Remember the size of this attribute
*/
toast_sizes[i] = VARSIZE_ANY(new_value);
}
else
{
/*
* Not a varlena attribute, plain storage always
*/
toast_action[i] = 'p';
}
}
/* ----------
* Compress and/or save external until data fits into target length
*
* 1: Inline compress attributes with attstorage 'x', and store very
* large attributes with attstorage 'x' or 'e' external immediately
* 2: Store attributes with attstorage 'x' or 'e' external
* 3: Inline compress attributes with attstorage 'm'
* 4: Store attributes with attstorage 'm' external
* ----------
*/
/* compute header overhead --- this should match heap_form_tuple() */
hoff = offsetof(HeapTupleHeaderData, t_bits);
if (has_nulls)
hoff += BITMAPLEN(numAttrs);
if (newtup->t_data->t_infomask & HEAP_HASOID)
hoff += sizeof(Oid);
hoff = MAXALIGN(hoff);
Assert(hoff == newtup->t_data->t_hoff);
/* now convert to a limit on the tuple data size */
maxDataLen = TOAST_TUPLE_TARGET - hoff;
/*
* Look for attributes with attstorage 'x' to compress. Also find large
* attributes with attstorage 'x' or 'e', and store them external.
*/
while (heap_compute_data_size(tupleDesc,
toast_values, toast_isnull) > maxDataLen)
{
int biggest_attno = -1;
int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE);
Datum old_value;
Datum new_value;
/*
* Search for the biggest yet unprocessed internal attribute
*/
for (i = 0; i < numAttrs; i++)
{
if (toast_action[i] != ' ')
continue;
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i])))
continue; /* can't happen, toast_action would be 'p' */
if (VARATT_IS_COMPRESSED(DatumGetPointer(toast_values[i])))
continue;
if (att[i]->attstorage != 'x' && att[i]->attstorage != 'e')
continue;
if (toast_sizes[i] > biggest_size)
{
biggest_attno = i;
biggest_size = toast_sizes[i];
}
}
if (biggest_attno < 0)
break;
/*
* Attempt to compress it inline, if it has attstorage 'x'
*/
i = biggest_attno;
if (att[i]->attstorage == 'x')
{
old_value = toast_values[i];
new_value = toast_compress_datum(old_value);
if (DatumGetPointer(new_value) != NULL)
{
/* successful compression */
if (toast_free[i])
pfree(DatumGetPointer(old_value));
toast_values[i] = new_value;
toast_free[i] = true;
toast_sizes[i] = VARSIZE(DatumGetPointer(toast_values[i]));
need_change = true;
need_free = true;
}
else
{
/* incompressible, ignore on subsequent compression passes */
toast_action[i] = 'x';
}
}
else
{
/* has attstorage 'e', ignore on subsequent compression passes */
toast_action[i] = 'x';
}
/*
* If this value is by itself more than maxDataLen (after compression
* if any), push it out to the toast table immediately, if possible.
* This avoids uselessly compressing other fields in the common case
* where we have one long field and several short ones.
*
* XXX maybe the threshold should be less than maxDataLen?
*/
if (toast_sizes[i] > maxDataLen &&
rel->rd_rel->reltoastrelid != InvalidOid)
{
old_value = toast_values[i];
toast_action[i] = 'p';
toast_values[i] = toast_save_datum(rel, toast_values[i], options);
if (toast_free[i])
pfree(DatumGetPointer(old_value));
toast_free[i] = true;
need_change = true;
need_free = true;
}
}
/*
* Second we look for attributes of attstorage 'x' or 'e' that are still
* inline. But skip this if there's no toast table to push them to.
*/
while (heap_compute_data_size(tupleDesc,
toast_values, toast_isnull) > maxDataLen &&
rel->rd_rel->reltoastrelid != InvalidOid)
{
int biggest_attno = -1;
int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE);
Datum old_value;
/*------
* Search for the biggest yet inlined attribute with
* attstorage equals 'x' or 'e'
*------
*/
for (i = 0; i < numAttrs; i++)
{
if (toast_action[i] == 'p')
continue;
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i])))
continue; /* can't happen, toast_action would be 'p' */
if (att[i]->attstorage != 'x' && att[i]->attstorage != 'e')
continue;
if (toast_sizes[i] > biggest_size)
{
biggest_attno = i;
biggest_size = toast_sizes[i];
}
}
if (biggest_attno < 0)
break;
/*
* Store this external
*/
i = biggest_attno;
old_value = toast_values[i];
toast_action[i] = 'p';
toast_values[i] = toast_save_datum(rel, toast_values[i], options);
if (toast_free[i])
pfree(DatumGetPointer(old_value));
toast_free[i] = true;
need_change = true;
need_free = true;
}
/*
* Round 3 - this time we take attributes with storage 'm' into
* compression
*/
while (heap_compute_data_size(tupleDesc,
toast_values, toast_isnull) > maxDataLen)
{
int biggest_attno = -1;
int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE);
Datum old_value;
Datum new_value;
/*
* Search for the biggest yet uncompressed internal attribute
*/
for (i = 0; i < numAttrs; i++)
{
if (toast_action[i] != ' ')
continue;
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i])))
continue; /* can't happen, toast_action would be 'p' */
if (VARATT_IS_COMPRESSED(DatumGetPointer(toast_values[i])))
continue;
if (att[i]->attstorage != 'm')
continue;
if (toast_sizes[i] > biggest_size)
{
biggest_attno = i;
biggest_size = toast_sizes[i];
}
}
if (biggest_attno < 0)
break;
/*
* Attempt to compress it inline
*/
i = biggest_attno;
old_value = toast_values[i];
new_value = toast_compress_datum(old_value);
if (DatumGetPointer(new_value) != NULL)
{
/* successful compression */
if (toast_free[i])
pfree(DatumGetPointer(old_value));
toast_values[i] = new_value;
toast_free[i] = true;
toast_sizes[i] = VARSIZE(DatumGetPointer(toast_values[i]));
need_change = true;
need_free = true;
}
else
{
/* incompressible, ignore on subsequent compression passes */
toast_action[i] = 'x';
}
}
/*
* Finally we store attributes of type 'm' externally. At this point we
* increase the target tuple size, so that 'm' attributes aren't stored
* externally unless really necessary.
*/
maxDataLen = TOAST_TUPLE_TARGET_MAIN - hoff;
while (heap_compute_data_size(tupleDesc,
toast_values, toast_isnull) > maxDataLen &&
rel->rd_rel->reltoastrelid != InvalidOid)
{
int biggest_attno = -1;
int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE);
Datum old_value;
/*--------
* Search for the biggest yet inlined attribute with
* attstorage = 'm'
*--------
*/
for (i = 0; i < numAttrs; i++)
{
if (toast_action[i] == 'p')
continue;
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i])))
continue; /* can't happen, toast_action would be 'p' */
if (att[i]->attstorage != 'm')
continue;
if (toast_sizes[i] > biggest_size)
{
biggest_attno = i;
biggest_size = toast_sizes[i];
}
}
if (biggest_attno < 0)
break;
/*
* Store this external
*/
i = biggest_attno;
old_value = toast_values[i];
toast_action[i] = 'p';
toast_values[i] = toast_save_datum(rel, toast_values[i], options);
if (toast_free[i])
pfree(DatumGetPointer(old_value));
toast_free[i] = true;
need_change = true;
need_free = true;
}
/*
* In the case we toasted any values, we need to build a new heap tuple
* with the changed values.
*/
if (need_change)
{
HeapTupleHeader olddata = newtup->t_data;
HeapTupleHeader new_data;
int32 new_len;
int32 new_data_len;
/*
* Calculate the new size of the tuple. Header size should not
* change, but data size might.
*/
new_len = offsetof(HeapTupleHeaderData, t_bits);
if (has_nulls)
new_len += BITMAPLEN(numAttrs);
if (olddata->t_infomask & HEAP_HASOID)
new_len += sizeof(Oid);
new_len = MAXALIGN(new_len);
Assert(new_len == olddata->t_hoff);
new_data_len = heap_compute_data_size(tupleDesc,
toast_values, toast_isnull);
new_len += new_data_len;
/*
* Allocate and zero the space needed, and fill HeapTupleData fields.
*/
result_tuple = (HeapTuple) palloc0(HEAPTUPLESIZE + new_len);
result_tuple->t_len = new_len;
result_tuple->t_self = newtup->t_self;
result_tuple->t_tableOid = newtup->t_tableOid;
new_data = (HeapTupleHeader) ((char *) result_tuple + HEAPTUPLESIZE);
result_tuple->t_data = new_data;
/*
* Put the existing tuple header and the changed values into place
*/
memcpy(new_data, olddata, olddata->t_hoff);
heap_fill_tuple(tupleDesc,
toast_values,
toast_isnull,
(char *) new_data + olddata->t_hoff,
new_data_len,
&(new_data->t_infomask),
has_nulls ? new_data->t_bits : NULL);
}
else
result_tuple = newtup;
/*
* Free allocated temp values
*/
if (need_free)
for (i = 0; i < numAttrs; i++)
if (toast_free[i])
pfree(DatumGetPointer(toast_values[i]));
/*
* Delete external values from the old tuple
*/
if (need_delold)
for (i = 0; i < numAttrs; i++)
if (toast_delold[i])
toast_delete_datum(rel, toast_oldvalues[i]);
return result_tuple;
}
int64
datumstreamwrite_lob(DatumStreamWrite * acc,
Datum d,
AppendOnlyBlockDirectory *blockDirectory,
int colGroupNo,
bool addColAction)
{
uint8 *p;
int32 varLen;
Assert(acc);
Assert(acc->datumStreamVersion == DatumStreamVersion_Original ||
acc->datumStreamVersion == DatumStreamVersion_Dense ||
acc->datumStreamVersion == DatumStreamVersion_Dense_Enhanced);
if (acc->typeInfo.datumlen >= 0)
{
elog(ERROR, "Large object must be variable length objects (varlena)");
}
/*
* If the datum is toasted / compressed -- an error.
*/
if (VARATT_IS_EXTENDED(DatumGetPointer(d)))
{
elog(ERROR, "Expected large object / variable length objects (varlena) to be de-toasted and/or de-compressed at this point");
}
/*
* De-Toast Datum
*/
if (VARATT_IS_EXTERNAL(DatumGetPointer(d)))
{
d = PointerGetDatum(heap_tuple_fetch_attr(DatumGetPointer(d)));
}
p = (uint8 *) DatumGetPointer(d);
varLen = VARSIZE_ANY(p);
if (Debug_datumstream_write_print_large_varlena_info)
{
datumstreamwrite_print_large_varlena_info(
acc,
p);
}
/* Set the BlockFirstRowNum */
AppendOnlyStorageWrite_SetFirstRowNum(&acc->ao_write,
acc->blockFirstRowNum);
AppendOnlyStorageWrite_Content(
&acc->ao_write,
p,
varLen,
AOCSBK_BLOB,
/* rowCount */ 1);
/* Insert an entry to the block directory */
AppendOnlyBlockDirectory_InsertEntry(
blockDirectory,
colGroupNo,
acc->blockFirstRowNum,
AppendOnlyStorageWrite_LogicalBlockStartOffset(&acc->ao_write),
1, /*itemCount -- always just the lob just inserted */
addColAction);
return varLen;
}
/* ----------
* toast_insert_or_update -
*
* Delete no-longer-used toast-entries and create new ones to
* make the new tuple fit on INSERT or UPDATE
* ----------
*/
static void
toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
{
TupleDesc tupleDesc;
Form_pg_attribute *att;
int numAttrs;
int i;
bool old_isnull;
bool new_isnull;
bool need_change = false;
bool need_free = false;
bool need_delold = false;
bool has_nulls = false;
Size maxDataLen;
char toast_action[MaxHeapAttributeNumber];
char toast_nulls[MaxHeapAttributeNumber];
Datum toast_values[MaxHeapAttributeNumber];
int32 toast_sizes[MaxHeapAttributeNumber];
bool toast_free[MaxHeapAttributeNumber];
bool toast_delold[MaxHeapAttributeNumber];
/*
* Get the tuple descriptor, the number of and attribute descriptors
* and the location of the tuple values.
*/
tupleDesc = rel->rd_att;
numAttrs = tupleDesc->natts;
att = tupleDesc->attrs;
/* ----------
* Then collect information about the values given
*
* NOTE: toast_action[i] can have these values:
* ' ' default handling
* 'p' already processed --- don't touch it
* 'x' incompressible, but OK to move off
* ----------
*/
memset(toast_action, ' ', numAttrs * sizeof(char));
memset(toast_nulls, ' ', numAttrs * sizeof(char));
memset(toast_free, 0, numAttrs * sizeof(bool));
memset(toast_delold, 0, numAttrs * sizeof(bool));
for (i = 0; i < numAttrs; i++)
{
varattrib *old_value;
varattrib *new_value;
if (oldtup != NULL)
{
/*
* For UPDATE get the old and new values of this attribute
*/
old_value = (varattrib *) DatumGetPointer(
heap_getattr(oldtup, i + 1, tupleDesc, &old_isnull));
toast_values[i] =
heap_getattr(newtup, i + 1, tupleDesc, &new_isnull);
new_value = (varattrib *) DatumGetPointer(toast_values[i]);
/*
* If the old value is an external stored one, check if it has
* changed so we have to delete it later.
*/
if (!old_isnull && att[i]->attlen == -1 &&
VARATT_IS_EXTERNAL(old_value))
{
if (new_isnull || !VARATT_IS_EXTERNAL(new_value) ||
old_value->va_content.va_external.va_valueid !=
new_value->va_content.va_external.va_valueid ||
old_value->va_content.va_external.va_toastrelid !=
new_value->va_content.va_external.va_toastrelid)
{
/*
* The old external store value isn't needed any more
* after the update
*/
toast_delold[i] = true;
need_delold = true;
}
else
{
/*
* This attribute isn't changed by this update so we
* reuse the original reference to the old value in
* the new tuple.
*/
toast_action[i] = 'p';
toast_sizes[i] = VARATT_SIZE(toast_values[i]);
continue;
}
}
}
else
{
/*
* For INSERT simply get the new value
*/
toast_values[i] =
heap_getattr(newtup, i + 1, tupleDesc, &new_isnull);
}
/*
* Handle NULL attributes
*/
if (new_isnull)
{
toast_action[i] = 'p';
toast_nulls[i] = 'n';
has_nulls = true;
continue;
}
/*
* Now look at varsize attributes
*/
if (att[i]->attlen == -1)
{
/*
* If the table's attribute says PLAIN always, force it so.
*/
if (att[i]->attstorage == 'p')
toast_action[i] = 'p';
/*
* We took care of UPDATE above, so any external value we find
* still in the tuple must be someone else's we cannot reuse.
* Expand it to plain (and, probably, toast it again below).
*/
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i])))
{
toast_values[i] = PointerGetDatum(heap_tuple_untoast_attr(
(varattrib *) DatumGetPointer(toast_values[i])));
toast_free[i] = true;
need_change = true;
need_free = true;
}
/*
* Remember the size of this attribute
*/
toast_sizes[i] = VARATT_SIZE(DatumGetPointer(toast_values[i]));
}
else
{
/*
* Not a variable size attribute, plain storage always
*/
toast_action[i] = 'p';
toast_sizes[i] = att[i]->attlen;
}
}
/* ----------
* Compress and/or save external until data fits into target length
*
* 1: Inline compress attributes with attstorage 'x'
* 2: Store attributes with attstorage 'x' or 'e' external
* 3: Inline compress attributes with attstorage 'm'
* 4: Store attributes with attstorage 'm' external
* ----------
*/
maxDataLen = offsetof(HeapTupleHeaderData, t_bits);
if (has_nulls)
maxDataLen += BITMAPLEN(numAttrs);
maxDataLen = TOAST_TUPLE_TARGET - MAXALIGN(maxDataLen);
/*
* Look for attributes with attstorage 'x' to compress
*/
while (MAXALIGN(ComputeDataSize(tupleDesc, toast_values, toast_nulls)) >
maxDataLen)
{
int biggest_attno = -1;
int32 biggest_size = MAXALIGN(sizeof(varattrib));
Datum old_value;
Datum new_value;
/*
* Search for the biggest yet uncompressed internal attribute
*/
for (i = 0; i < numAttrs; i++)
{
if (toast_action[i] != ' ')
continue;
if (VARATT_IS_EXTENDED(toast_values[i]))
continue;
if (att[i]->attstorage != 'x')
continue;
if (toast_sizes[i] > biggest_size)
{
biggest_attno = i;
biggest_size = toast_sizes[i];
}
}
if (biggest_attno < 0)
break;
/*
* Attempt to compress it inline
*/
i = biggest_attno;
old_value = toast_values[i];
new_value = toast_compress_datum(old_value);
if (DatumGetPointer(new_value) != NULL)
{
/* successful compression */
if (toast_free[i])
pfree(DatumGetPointer(old_value));
toast_values[i] = new_value;
toast_free[i] = true;
toast_sizes[i] = VARATT_SIZE(toast_values[i]);
need_change = true;
need_free = true;
}
else
{
/*
* incompressible data, ignore on subsequent compression
* passes
*/
toast_action[i] = 'x';
}
}
/*
* Second we look for attributes of attstorage 'x' or 'e' that are
* still inline.
*/
while (MAXALIGN(ComputeDataSize(tupleDesc, toast_values, toast_nulls)) >
maxDataLen && rel->rd_rel->reltoastrelid != InvalidOid)
{
int biggest_attno = -1;
int32 biggest_size = MAXALIGN(sizeof(varattrib));
Datum old_value;
/*------
* Search for the biggest yet inlined attribute with
* attstorage equals 'x' or 'e'
*------
*/
for (i = 0; i < numAttrs; i++)
{
if (toast_action[i] == 'p')
continue;
if (VARATT_IS_EXTERNAL(toast_values[i]))
continue;
if (att[i]->attstorage != 'x' && att[i]->attstorage != 'e')
continue;
if (toast_sizes[i] > biggest_size)
{
biggest_attno = i;
biggest_size = toast_sizes[i];
}
}
if (biggest_attno < 0)
break;
/*
* Store this external
*/
i = biggest_attno;
old_value = toast_values[i];
toast_action[i] = 'p';
toast_values[i] = toast_save_datum(rel, toast_values[i]);
if (toast_free[i])
pfree(DatumGetPointer(old_value));
toast_free[i] = true;
toast_sizes[i] = VARATT_SIZE(toast_values[i]);
need_change = true;
need_free = true;
}
/*
* Round 3 - this time we take attributes with storage 'm' into
* compression
*/
while (MAXALIGN(ComputeDataSize(tupleDesc, toast_values, toast_nulls)) >
maxDataLen)
{
int biggest_attno = -1;
int32 biggest_size = MAXALIGN(sizeof(varattrib));
Datum old_value;
Datum new_value;
/*
* Search for the biggest yet uncompressed internal attribute
*/
for (i = 0; i < numAttrs; i++)
{
if (toast_action[i] != ' ')
continue;
if (VARATT_IS_EXTENDED(toast_values[i]))
continue;
if (att[i]->attstorage != 'm')
continue;
if (toast_sizes[i] > biggest_size)
{
biggest_attno = i;
biggest_size = toast_sizes[i];
}
}
if (biggest_attno < 0)
break;
/*
* Attempt to compress it inline
*/
i = biggest_attno;
old_value = toast_values[i];
new_value = toast_compress_datum(old_value);
if (DatumGetPointer(new_value) != NULL)
{
/* successful compression */
if (toast_free[i])
pfree(DatumGetPointer(old_value));
toast_values[i] = new_value;
toast_free[i] = true;
toast_sizes[i] = VARATT_SIZE(toast_values[i]);
need_change = true;
need_free = true;
}
else
{
/*
* incompressible data, ignore on subsequent compression
* passes
*/
toast_action[i] = 'x';
}
}
/*
* Finally we store attributes of type 'm' external
*/
while (MAXALIGN(ComputeDataSize(tupleDesc, toast_values, toast_nulls)) >
maxDataLen && rel->rd_rel->reltoastrelid != InvalidOid)
{
int biggest_attno = -1;
int32 biggest_size = MAXALIGN(sizeof(varattrib));
Datum old_value;
/*--------
* Search for the biggest yet inlined attribute with
* attstorage = 'm'
*--------
*/
for (i = 0; i < numAttrs; i++)
{
if (toast_action[i] == 'p')
continue;
if (VARATT_IS_EXTERNAL(toast_values[i]))
continue;
if (att[i]->attstorage != 'm')
continue;
if (toast_sizes[i] > biggest_size)
{
biggest_attno = i;
biggest_size = toast_sizes[i];
}
}
if (biggest_attno < 0)
break;
/*
* Store this external
*/
i = biggest_attno;
old_value = toast_values[i];
toast_action[i] = 'p';
toast_values[i] = toast_save_datum(rel, toast_values[i]);
if (toast_free[i])
pfree(DatumGetPointer(old_value));
toast_free[i] = true;
toast_sizes[i] = VARATT_SIZE(toast_values[i]);
need_change = true;
need_free = true;
}
/*
* In the case we toasted any values, we need to build a new heap
* tuple with the changed values.
*/
if (need_change)
{
HeapTupleHeader olddata = newtup->t_data;
char *new_data;
int32 new_len;
/*
* Calculate the new size of the tuple. Header size should not
* change, but data size might.
*/
new_len = offsetof(HeapTupleHeaderData, t_bits);
if (has_nulls)
new_len += BITMAPLEN(numAttrs);
if (olddata->t_infomask & HEAP_HASOID)
new_len += sizeof(Oid);
new_len = MAXALIGN(new_len);
Assert(new_len == olddata->t_hoff);
new_len += ComputeDataSize(tupleDesc, toast_values, toast_nulls);
/*
* Allocate new tuple in same context as old one.
*/
new_data = (char *) MemoryContextAlloc(newtup->t_datamcxt, new_len);
newtup->t_data = (HeapTupleHeader) new_data;
newtup->t_len = new_len;
/*
* Put the tuple header and the changed values into place
*/
memcpy(new_data, olddata, olddata->t_hoff);
DataFill((char *) new_data + olddata->t_hoff,
tupleDesc,
toast_values,
toast_nulls,
&(newtup->t_data->t_infomask),
has_nulls ? newtup->t_data->t_bits : NULL);
/*
* In the case we modified a previously modified tuple again, free
* the memory from the previous run
*/
if ((char *) olddata != ((char *) newtup + HEAPTUPLESIZE))
pfree(olddata);
}
/*
* Free allocated temp values
*/
if (need_free)
for (i = 0; i < numAttrs; i++)
if (toast_free[i])
pfree(DatumGetPointer(toast_values[i]));
/*
* Delete external values from the old tuple
*/
if (need_delold)
for (i = 0; i < numAttrs; i++)
if (toast_delold[i])
toast_delete_datum(rel,
heap_getattr(oldtup, i + 1, tupleDesc, &old_isnull));
}
/* ----------
* heap_tuple_untoast_attr_slice -
*
* Public entry point to get back part of a toasted value
* from compression or external storage.
* ----------
*/
struct varlena *
heap_tuple_untoast_attr_slice(struct varlena * attr,
int32 sliceoffset, int32 slicelength)
{
struct varlena *preslice;
struct varlena *result;
char *attrdata;
int32 attrsize;
if (VARATT_IS_EXTERNAL(attr))
{
struct varatt_external toast_pointer;
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
/* fast path for non-compressed external datums */
if (!VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer))
return toast_fetch_datum_slice(attr, sliceoffset, slicelength);
/* fetch it back (compressed marker will get set automatically) */
preslice = toast_fetch_datum(attr);
}
else
preslice = attr;
if (VARATT_IS_COMPRESSED(preslice))
{
PGLZ_Header *tmp = (PGLZ_Header *) preslice;
Size size = PGLZ_RAW_SIZE(tmp) + VARHDRSZ;
preslice = (struct varlena *) palloc(size);
SET_VARSIZE(preslice, size);
pglz_decompress(tmp, VARDATA(preslice));
if (tmp != (PGLZ_Header *) attr)
pfree(tmp);
}
if (VARATT_IS_SHORT(preslice))
{
attrdata = VARDATA_SHORT(preslice);
attrsize = VARSIZE_SHORT(preslice) - VARHDRSZ_SHORT;
}
else
{
attrdata = VARDATA(preslice);
attrsize = VARSIZE(preslice) - VARHDRSZ;
}
/* slicing of datum for compressed cases and plain value */
if (sliceoffset >= attrsize)
{
sliceoffset = 0;
slicelength = 0;
}
if (((sliceoffset + slicelength) > attrsize) || slicelength < 0)
slicelength = attrsize - sliceoffset;
result = (struct varlena *) palloc(slicelength + VARHDRSZ);
SET_VARSIZE(result, slicelength + VARHDRSZ);
memcpy(VARDATA(result), attrdata + sliceoffset, slicelength);
if (preslice != attr)
pfree(preslice);
return result;
}
/* ----------
* toast_fetch_datum_slice -
*
* Reconstruct a segment of a Datum from the chunks saved
* in the toast relation
* ----------
*/
static struct varlena *
toast_fetch_datum_slice(struct varlena * attr, int32 sliceoffset, int32 length)
{
Relation toastrel;
Relation toastidx;
ScanKeyData toastkey[3];
int nscankeys;
SysScanDesc toastscan;
HeapTuple ttup;
TupleDesc toasttupDesc;
struct varlena *result;
struct varatt_external toast_pointer;
int32 attrsize;
int32 residx;
int32 nextidx;
int numchunks;
int startchunk;
int endchunk;
int32 startoffset;
int32 endoffset;
int totalchunks;
Pointer chunk;
bool isnull;
char *chunkdata;
int32 chunksize;
int32 chcpystrt;
int32 chcpyend;
Assert(VARATT_IS_EXTERNAL(attr));
/* Must copy to access aligned fields */
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
/*
* It's nonsense to fetch slices of a compressed datum -- this isn't lo_*
* we can't return a compressed datum which is meaningful to toast later
*/
Assert(!VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer));
attrsize = toast_pointer.va_extsize;
totalchunks = ((attrsize - 1) / TOAST_MAX_CHUNK_SIZE) + 1;
if (sliceoffset >= attrsize)
{
sliceoffset = 0;
length = 0;
}
if (((sliceoffset + length) > attrsize) || length < 0)
length = attrsize - sliceoffset;
result = (struct varlena *) palloc(length + VARHDRSZ);
if (VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer))
SET_VARSIZE_COMPRESSED(result, length + VARHDRSZ);
else
SET_VARSIZE(result, length + VARHDRSZ);
if (length == 0)
return result; /* Can save a lot of work at this point! */
startchunk = sliceoffset / TOAST_MAX_CHUNK_SIZE;
endchunk = (sliceoffset + length - 1) / TOAST_MAX_CHUNK_SIZE;
numchunks = (endchunk - startchunk) + 1;
startoffset = sliceoffset % TOAST_MAX_CHUNK_SIZE;
endoffset = (sliceoffset + length - 1) % TOAST_MAX_CHUNK_SIZE;
/*
* Open the toast relation and its index
*/
toastrel = heap_open(toast_pointer.va_toastrelid, AccessShareLock);
toasttupDesc = toastrel->rd_att;
toastidx = index_open(toastrel->rd_rel->reltoastidxid, AccessShareLock);
/*
* Setup a scan key to fetch from the index. This is either two keys or
* three depending on the number of chunks.
*/
ScanKeyInit(&toastkey[0],
(AttrNumber) 1,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(toast_pointer.va_valueid));
/*
* Use equality condition for one chunk, a range condition otherwise:
*/
if (numchunks == 1)
{
ScanKeyInit(&toastkey[1],
(AttrNumber) 2,
BTEqualStrategyNumber, F_INT4EQ,
Int32GetDatum(startchunk));
nscankeys = 2;
}
else
{
ScanKeyInit(&toastkey[1],
(AttrNumber) 2,
BTGreaterEqualStrategyNumber, F_INT4GE,
Int32GetDatum(startchunk));
ScanKeyInit(&toastkey[2],
(AttrNumber) 2,
BTLessEqualStrategyNumber, F_INT4LE,
Int32GetDatum(endchunk));
nscankeys = 3;
}
/*
* Read the chunks by index
*
* The index is on (valueid, chunkidx) so they will come in order
*/
nextidx = startchunk;
toastscan = systable_beginscan_ordered(toastrel, toastidx,
SnapshotToast, nscankeys, toastkey);
while ((ttup = systable_getnext_ordered(toastscan, ForwardScanDirection)) != NULL)
{
/*
* Have a chunk, extract the sequence number and the data
*/
residx = DatumGetInt32(fastgetattr(ttup, 2, toasttupDesc, &isnull));
Assert(!isnull);
chunk = DatumGetPointer(fastgetattr(ttup, 3, toasttupDesc, &isnull));
Assert(!isnull);
if (!VARATT_IS_EXTENDED(chunk))
{
chunksize = VARSIZE(chunk) - VARHDRSZ;
chunkdata = VARDATA(chunk);
}
else if (VARATT_IS_SHORT(chunk))
{
/* could happen due to heap_form_tuple doing its thing */
chunksize = VARSIZE_SHORT(chunk) - VARHDRSZ_SHORT;
chunkdata = VARDATA_SHORT(chunk);
}
else
{
/* should never happen */
elog(ERROR, "found toasted toast chunk for toast value %u in %s",
toast_pointer.va_valueid,
RelationGetRelationName(toastrel));
chunksize = 0; /* keep compiler quiet */
chunkdata = NULL;
}
/*
* Some checks on the data we've found
*/
if ((residx != nextidx) || (residx > endchunk) || (residx < startchunk))
elog(ERROR, "unexpected chunk number %d (expected %d) for toast value %u in %s",
residx, nextidx,
toast_pointer.va_valueid,
RelationGetRelationName(toastrel));
if (residx < totalchunks - 1)
{
if (chunksize != TOAST_MAX_CHUNK_SIZE)
elog(ERROR, "unexpected chunk size %d (expected %d) in chunk %d of %d for toast value %u in %s when fetching slice",
chunksize, (int) TOAST_MAX_CHUNK_SIZE,
residx, totalchunks,
toast_pointer.va_valueid,
RelationGetRelationName(toastrel));
}
else if (residx == totalchunks - 1)
{
if ((residx * TOAST_MAX_CHUNK_SIZE + chunksize) != attrsize)
elog(ERROR, "unexpected chunk size %d (expected %d) in final chunk %d for toast value %u in %s when fetching slice",
chunksize,
(int) (attrsize - residx * TOAST_MAX_CHUNK_SIZE),
residx,
toast_pointer.va_valueid,
RelationGetRelationName(toastrel));
}
else
elog(ERROR, "unexpected chunk number %d (out of range %d..%d) for toast value %u in %s",
residx,
0, totalchunks - 1,
toast_pointer.va_valueid,
RelationGetRelationName(toastrel));
/*
* Copy the data into proper place in our result
*/
chcpystrt = 0;
chcpyend = chunksize - 1;
if (residx == startchunk)
chcpystrt = startoffset;
if (residx == endchunk)
chcpyend = endoffset;
memcpy(VARDATA(result) +
(residx * TOAST_MAX_CHUNK_SIZE - sliceoffset) + chcpystrt,
chunkdata + chcpystrt,
(chcpyend - chcpystrt) + 1);
nextidx++;
}
/*
* Final checks that we successfully fetched the datum
*/
if (nextidx != (endchunk + 1))
elog(ERROR, "missing chunk number %d for toast value %u in %s",
nextidx,
toast_pointer.va_valueid,
RelationGetRelationName(toastrel));
/*
* End scan and close relations
*/
systable_endscan_ordered(toastscan);
index_close(toastidx, AccessShareLock);
heap_close(toastrel, AccessShareLock);
return result;
}
/*
* 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, AccessShareLock);
tupdesc = RelationGetDescr(rel);
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 = TupleDescAttr(tupdesc, i);
/*
* 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;
else
is_null = (t_infomask & HEAP_HASNULL) && att_isnull(i, t_bits);
if (!is_null)
{
int len;
if (attr->attlen == -1)
{
off = att_align_pointer(off, attr->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, attr->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, attr->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")));
relation_close(rel, AccessShareLock);
return makeArrayResult(raw_attrs, CurrentMemoryContext);
}
