Function command_update

pg_documentdb/src/commands/update.c:518–554

* command_update handles a single update on a collection. */

 * command_update handles a single update on a collection.
 */
Datum
command_update(PG_FUNCTION_ARGS)
{
	if (PG_ARGISNULL(1))
	{
		ereport(ERROR, (errmsg("update document cannot be NULL")));
	}

	Datum databaseNameDatum = PG_ARGISNULL(0) ? (Datum) 0 : PG_GETARG_DATUM(0);
	pgbson *updateSpec = PG_GETARG_PGBSON(1);

	pgbsonsequence *updateDocs = PG_GETARG_MAYBE_NULL_PGBSON_SEQUENCE(2);

	text *transactionId = NULL;
	if (!PG_ARGISNULL(3))
	{
		transactionId = PG_GETARG_TEXT_P(3);
	}

	ReportFeatureUsage(FEATURE_COMMAND_UPDATE);

	/* fetch TupleDesc for return value, not interested in resultTypeId */
	Oid *resultTypeId = NULL;
	TupleDesc resultTupDesc;
	TypeFuncClass resultTypeClass =
		get_call_result_type(fcinfo, resultTypeId, &resultTupDesc);

	if (resultTypeClass != TYPEFUNC_COMPOSITE)
	{
		ereport(ERROR, (errmsg("return type must be a row type")));
	}

	HeapTuple resultTuple = PerformUpdateCore(&databaseNameDatum, updateSpec, updateDocs,
											  transactionId, resultTupDesc,
											  WriteMode_Txn_Func, CurrentMemoryContext);
	PG_RETURN_DATUM(HeapTupleGetDatum(resultTuple));
}


inline static bool