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## Proposed changes Add transaction for the operation of insert. It will cost less time than non-transaction(it will cost 1/1000 time) when you want to insert a amount of rows. ### Syntax ``` BEGIN [ WITH LABEL label]; INSERT INTO table_name ... [COMMIT | ROLLBACK]; ``` ### Example commit a transaction: ``` begin; insert into Tbl values(11, 22, 33); commit; ``` rollback a transaction: ``` begin; insert into Tbl values(11, 22, 33); rollback; ``` commit a transaction with label: ``` begin with label test_label; insert into Tbl values(11, 22, 33); commit; ``` ### Description ``` begin: begin a transaction, the next insert will execute in the transaction until commit/rollback; commit: commit the transaction, the data in the transaction will be inserted into the table; rollback: abort the transaction, nothing will be inserted into the table; ``` ### The main realization principle: ``` 1. begin a transaction in the session. next sql is executed in the transaction; 2. insert sql will be parser and get the database name and table name, they will be used to select a be and create a pipe to accept data; 3. all inserted values will be sent to the be and write into the pipe; 4. a thread will get the data from the pipe, then write them to disk; 5. commit will complete this transaction and make these data visible; 6. rollback will abort this transaction ``` ### Some restrictions on the use of update syntax. 1. Only ```insert``` can be called in a transaction. 2. If something error happened, ```commit``` will not succeed, it will ```rollback``` directly; 3. By default, if part of insert in the transaction is invalid, ```commit``` will only insert the other correct data into the table. 4. If you need ```commit``` return failed when any insert in the transaction is invalid, you need execute ```set enable_insert_strict = true``` before ```begin```.
94 lines
2.4 KiB
Markdown
94 lines
2.4 KiB
Markdown
---
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{
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"title": "BEGIN",
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"language": "zh-CN"
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}
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---
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<!--
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Licensed to the Apache Software Foundation (ASF) under one
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or more contributor license agreements. See the NOTICE file
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distributed with this work for additional information
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regarding copyright ownership. The ASF licenses this file
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to you under the Apache License, Version 2.0 (the
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"License"); you may not use this file except in compliance
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with the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing,
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software distributed under the License is distributed on an
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"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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KIND, either express or implied. See the License for the
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specific language governing permissions and limitations
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under the License.
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-->
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# BEGIN, COMMIT, ROLLBACK
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## Description
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### Syntax
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```
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BEGIN;
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INSERT INTO table_name ...
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COMMIT;
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```
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```
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BEGIN [ WITH LABEL label];
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INSERT INTO table_name ...
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ROLLBACK;
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```
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### Parameters
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> label: 用于指定当前事务的标签名。
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### Note
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事务只能对insert使用，而不能对update和delete使用，当指定标签时，可通过以下命令检查事务的运行状态： `SHOW TRANSACTION WHERE LABEL = 'label'`
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## example
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1. 开启一个事务，不指定标签，执行insert后提交。
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```
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BEGIN
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INSERT INTO test VALUES (1, 2);
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INSERT INTO test (c1, c2) VALUES (1, 2);
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INSERT INTO test (c1, c2) VALUES (1, DEFAULT);
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INSERT INTO test (c1) VALUES (1);
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COMMIT:
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```
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所有在`begin`和`commit`之间的数据会被插入到test表中。
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2. 开启一个事务，不指定标签，执行insert后，回滚。
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```
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BEGIN
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INSERT INTO test VALUES (1, 2);
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INSERT INTO test (c1, c2) VALUES (1, 2);
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INSERT INTO test (c1, c2) VALUES (1, DEFAULT);
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INSERT INTO test (c1) VALUES (1);
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ROLLBACK:
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```
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所有在`begin`和`commit`之间的数据会取消，没有任何数据插入到test表中。
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3. 开启一个事务，指定标签为test_label1，执行insert后提交。
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```
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BEGIN WITH LABEL test_label1
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INSERT INTO test VALUES (1, 2);
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INSERT INTO test (c1, c2) VALUES (1, 2);
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INSERT INTO test (c1, c2) VALUES (1, DEFAULT);
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INSERT INTO test (c1) VALUES (1);
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COMMIT:
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```
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所有在`begin`和`commit`之间的数据会被插入到test表中。
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标签`test_label1`用于标记该事务，可以通过以下命令来检查事务的状态：`SHOW TRANSACTION WHERE LABEL = 'test_label1'`。
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## keyword
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BEGIN, COMMIT, ROLLBACK
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