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Java > Open Source Codes > org > apache > derby > iapi > store > access > DynamicCompiledOpenConglomInfo

1 /*
3    Derby - Class
5    Licensed to the Apache Software Foundation (ASF) under one or more
6    contributor license agreements. See the NOTICE file distributed with
7    this work for additional information regarding copyright ownership.
8    The ASF licenses this file to you under the Apache License, Version 2.0
9    (the "License"); you may not use this file except in compliance with
10    the License. You may obtain a copy of the License at
14    Unless required by applicable law or agreed to in writing, software
15    distributed under the License is distributed on an "AS IS" BASIS,
16    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17    See the License for the specific language governing permissions and
18    limitations under the License.
20  */

22 package;
24 import org.apache.derby.iapi.error.StandardException;
27 /**
29   Information that can be "compiled" and reused per transaction per
30   open operation. This information is read only by the caller and
31   written by user. Likely information kept in this object is a set of
32   scratch buffers which will be used by openScan() and thus must not be
33   shared across multiple threads/openScan()'s/openConglomerate()'s. The
34   goal is to optimize repeated operations like btree inserts, by allowing a
35   set of scratch buffers to be reused across a repeated execution of a statement
36   like an insert/delete/update.
38   This information is obtained from the getDynamicCompiledConglomInfo(conglomid)
39   method call. It can then be used in openConglomerate() and openScan() calls
40   for increased performance. The information is only valid until the next
41   ddl operation is performed on the conglomerate. It is up to the caller to
42   provide an invalidation methodology.
44   The dynamic info is a set of variables to be used in a given ScanController
45   or ConglomerateController. It can only be used in one controller at a time.
46   It is up to the caller to insure the correct thread access to this info. The
47   type of info in this is a scratch template for btree traversal, other scratch
48   variables for qualifier evaluation, ...
50 **/

52 public interface DynamicCompiledOpenConglomInfo
53 {
54 }
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