| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| /** |
| * Runtime code-generation, compilation and bytecode-manipulation utilities. |
| * |
| * To achieve optimal performance in a dynamic schema environment, Drill |
| * includes a complete code generation system for generating type-specific Java |
| * code for most of its physical operators. This generated code is used for |
| * scalar expression evaluation as well as value transfers between record |
| * batches. As a new schema arrives at an operator, the schema change will be |
| * detected and prompt runtime code generation. This runtime-generated code will |
| * evaluate the expressions needed for the operator to process the incoming |
| * data. As the same code will often be run on a number of nodes in the cluster, |
| * compiled classes are stored in the distributed cache to avoid the need to re- |
| * compile and JIT-optimize the same code on every machine. |
| */ |
| package org.apache.drill.exec.compile; |
