Exemplo n.º 1
0
Datum
make_tuple_indirect(PG_FUNCTION_ARGS)
{
	HeapTupleHeader rec = PG_GETARG_HEAPTUPLEHEADER(0);
	HeapTupleData tuple;
	int			ncolumns;
	Datum	   *values;
	bool	   *nulls;

	Oid			tupType;
	int32		tupTypmod;
	TupleDesc	tupdesc;

	HeapTuple	newtup;

	int			i;

	MemoryContext old_context;

	/* Extract type info from the tuple itself */
	tupType = HeapTupleHeaderGetTypeId(rec);
	tupTypmod = HeapTupleHeaderGetTypMod(rec);
	tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
	ncolumns = tupdesc->natts;

	/* Build a temporary HeapTuple control structure */
	tuple.t_len = HeapTupleHeaderGetDatumLength(rec);
	ItemPointerSetInvalid(&(tuple.t_self));
	tuple.t_tableOid = InvalidOid;
	tuple.t_data = rec;

	values = (Datum *) palloc(ncolumns * sizeof(Datum));
	nulls = (bool *) palloc(ncolumns * sizeof(bool));

	heap_deform_tuple(&tuple, tupdesc, values, nulls);

	old_context = MemoryContextSwitchTo(TopTransactionContext);

	for (i = 0; i < ncolumns; i++)
	{
		struct varlena *attr;
		struct varlena *new_attr;
		struct varatt_indirect redirect_pointer;

		/* only work on existing, not-null varlenas */
		if (TupleDescAttr(tupdesc, i)->attisdropped ||
			nulls[i] ||
			TupleDescAttr(tupdesc, i)->attlen != -1)
			continue;

		attr = (struct varlena *) DatumGetPointer(values[i]);

		/* don't recursively indirect */
		if (VARATT_IS_EXTERNAL_INDIRECT(attr))
			continue;

		/* copy datum, so it still lives later */
		if (VARATT_IS_EXTERNAL_ONDISK(attr))
			attr = heap_tuple_fetch_attr(attr);
		else
		{
			struct varlena *oldattr = attr;

			attr = palloc0(VARSIZE_ANY(oldattr));
			memcpy(attr, oldattr, VARSIZE_ANY(oldattr));
		}

		/* build indirection Datum */
		new_attr = (struct varlena *) palloc0(INDIRECT_POINTER_SIZE);
		redirect_pointer.pointer = attr;
		SET_VARTAG_EXTERNAL(new_attr, VARTAG_INDIRECT);
		memcpy(VARDATA_EXTERNAL(new_attr), &redirect_pointer,
			   sizeof(redirect_pointer));

		values[i] = PointerGetDatum(new_attr);
	}

	newtup = heap_form_tuple(tupdesc, values, nulls);
	pfree(values);
	pfree(nulls);
	ReleaseTupleDesc(tupdesc);

	MemoryContextSwitchTo(old_context);

	/*
	 * We intentionally don't use PG_RETURN_HEAPTUPLEHEADER here, because that
	 * would cause the indirect toast pointers to be flattened out of the
	 * tuple immediately, rendering subsequent testing irrelevant.  So just
	 * return the HeapTupleHeader pointer as-is.  This violates the general
	 * rule that composite Datums shouldn't contain toast pointers, but so
	 * long as the regression test scripts don't insert the result of this
	 * function into a container type (record, array, etc) it should be OK.
	 */
	PG_RETURN_POINTER(newtup->t_data);
}
/*
 * Write a tuple to the outputstream, in the most efficient format possible.
 */
static void
pglogical_write_tuple(StringInfo out, PGLogicalOutputData *data,
					   Relation rel, HeapTuple tuple)
{
	TupleDesc	desc;
	Datum		values[MaxTupleAttributeNumber];
	bool		isnull[MaxTupleAttributeNumber];
	int			i;
	uint16		nliveatts = 0;

	desc = RelationGetDescr(rel);

	pq_sendbyte(out, 'T');			/* sending TUPLE */

	for (i = 0; i < desc->natts; i++)
	{
		if (desc->attrs[i]->attisdropped)
			continue;
		nliveatts++;
	}
	pq_sendint(out, nliveatts, 2);

	/* try to allocate enough memory from the get go */
	enlargeStringInfo(out, tuple->t_len +
					  nliveatts * (1 + 4));

	/*
	 * XXX: should this prove to be a relevant bottleneck, it might be
	 * interesting to inline heap_deform_tuple() here, we don't actually need
	 * the information in the form we get from it.
	 */
	heap_deform_tuple(tuple, desc, values, isnull);

	for (i = 0; i < desc->natts; i++)
	{
		HeapTuple	typtup;
		Form_pg_type typclass;
		Form_pg_attribute att = desc->attrs[i];
		char		transfer_type;

		/* skip dropped columns */
		if (att->attisdropped)
			continue;

		if (isnull[i])
		{
			pq_sendbyte(out, 'n');	/* null column */
			continue;
		}
		else if (att->attlen == -1 && VARATT_IS_EXTERNAL_ONDISK(values[i]))
		{
			pq_sendbyte(out, 'u');	/* unchanged toast column */
			continue;
		}

		typtup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(att->atttypid));
		if (!HeapTupleIsValid(typtup))
			elog(ERROR, "cache lookup failed for type %u", att->atttypid);
		typclass = (Form_pg_type) GETSTRUCT(typtup);

		transfer_type = decide_datum_transfer(att, typclass,
											  data->allow_internal_basetypes,
											  data->allow_binary_basetypes);
        pq_sendbyte(out, transfer_type);
		switch (transfer_type)
		{
			case 'b':	/* internal-format binary data follows */

				/* pass by value */
				if (att->attbyval)
				{
					pq_sendint(out, att->attlen, 4); /* length */

					enlargeStringInfo(out, att->attlen);
					store_att_byval(out->data + out->len, values[i],
									att->attlen);
					out->len += att->attlen;
					out->data[out->len] = '\0';
				}
				/* fixed length non-varlena pass-by-reference type */
				else if (att->attlen > 0)
				{
					pq_sendint(out, att->attlen, 4); /* length */

					appendBinaryStringInfo(out, DatumGetPointer(values[i]),
										   att->attlen);
				}
				/* varlena type */
				else if (att->attlen == -1)
				{
					char *data = DatumGetPointer(values[i]);

					/* send indirect datums inline */
					if (VARATT_IS_EXTERNAL_INDIRECT(values[i]))
					{
						struct varatt_indirect redirect;
						VARATT_EXTERNAL_GET_POINTER(redirect, data);
						data = (char *) redirect.pointer;
					}

					Assert(!VARATT_IS_EXTERNAL(data));

					pq_sendint(out, VARSIZE_ANY(data), 4); /* length */

					appendBinaryStringInfo(out, data, VARSIZE_ANY(data));
				}
				else
					elog(ERROR, "unsupported tuple type");

				break;

			case 's': /* binary send/recv data follows */
				{
					bytea	   *outputbytes;
					int			len;

					outputbytes = OidSendFunctionCall(typclass->typsend,
													  values[i]);

					len = VARSIZE(outputbytes) - VARHDRSZ;
					pq_sendint(out, len, 4); /* length */
					pq_sendbytes(out, VARDATA(outputbytes), len); /* data */
					pfree(outputbytes);
				}
				break;

			default:
				{
					char   	   *outputstr;
					int			len;

					outputstr =	OidOutputFunctionCall(typclass->typoutput,
													  values[i]);
					len = strlen(outputstr) + 1;
					pq_sendint(out, len, 4); /* length */
					appendBinaryStringInfo(out, outputstr, len); /* data */
					pfree(outputstr);
				}
		}

		ReleaseSysCache(typtup);
	}
}
Exemplo n.º 3
0
/*
 * 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);
}
Exemplo n.º 4
0
Datum
make_tuple_indirect(PG_FUNCTION_ARGS)
{
	HeapTupleHeader rec = PG_GETARG_HEAPTUPLEHEADER(0);
	HeapTupleData tuple;
	int			ncolumns;
	Datum	   *values;
	bool	   *nulls;

	Oid			tupType;
	int32		tupTypmod;
	TupleDesc	tupdesc;

	HeapTuple	newtup;

	int			i;

	MemoryContext old_context;

	/* Extract type info from the tuple itself */
	tupType = HeapTupleHeaderGetTypeId(rec);
	tupTypmod = HeapTupleHeaderGetTypMod(rec);
	tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
	ncolumns = tupdesc->natts;

	/* Build a temporary HeapTuple control structure */
	tuple.t_len = HeapTupleHeaderGetDatumLength(rec);
	ItemPointerSetInvalid(&(tuple.t_self));
	tuple.t_tableOid = InvalidOid;
	tuple.t_data = rec;

	values = (Datum *) palloc(ncolumns * sizeof(Datum));
	nulls = (bool *) palloc(ncolumns * sizeof(bool));

	heap_deform_tuple(&tuple, tupdesc, values, nulls);

	old_context = MemoryContextSwitchTo(TopTransactionContext);

	for (i = 0; i < ncolumns; i++)
	{
		struct varlena *attr;
		struct varlena *new_attr;
		struct varatt_indirect redirect_pointer;

		/* only work on existing, not-null varlenas */
		if (tupdesc->attrs[i]->attisdropped ||
			nulls[i] ||
			tupdesc->attrs[i]->attlen != -1)
			continue;

		attr = (struct varlena *) DatumGetPointer(values[i]);

		/* don't recursively indirect */
		if (VARATT_IS_EXTERNAL_INDIRECT(attr))
			continue;

		/* copy datum, so it still lives later */
		if (VARATT_IS_EXTERNAL_ONDISK(attr))
			attr = heap_tuple_fetch_attr(attr);
		else
		{
			struct varlena *oldattr = attr;
			attr = palloc0(VARSIZE_ANY(oldattr));
			memcpy(attr, oldattr, VARSIZE_ANY(oldattr));
		}

		/* build indirection Datum */
		new_attr = (struct varlena *) palloc0(INDIRECT_POINTER_SIZE);
		redirect_pointer.pointer = attr;
		SET_VARTAG_EXTERNAL(new_attr, VARTAG_INDIRECT);
		memcpy(VARDATA_EXTERNAL(new_attr), &redirect_pointer,
			   sizeof(redirect_pointer));

		values[i] = PointerGetDatum(new_attr);
	}

	newtup = heap_form_tuple(tupdesc, values, nulls);
	pfree(values);
	pfree(nulls);
	ReleaseTupleDesc(tupdesc);

	MemoryContextSwitchTo(old_context);

	PG_RETURN_HEAPTUPLEHEADER(newtup->t_data);
}