MySQL binlog_ignore_db 參數最全解析

前言：

通過前面文章學習，咱們知道 binlog 會記錄數據庫全部執行的 DDL 和 DML 語句（除了數據查詢語句select、show等）。注意默認狀況下會記錄全部庫的操做，那麼若是咱們有另類需求，好比說只讓某個庫記錄 binglog 或排除某個庫記錄 binlog ，是否支持此類需求呢？本篇文章咱們一塊兒來看下。

1. binlog_do_db 與 binlog_ignore_db

當數據庫實例開啓 binlog 時，咱們執行 show master status 命令，會看到有 Binlog_Do_DB 與 Binlog_Ignore_DB 選項。

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000009 |   282838 |              |                  |                   |
+---------------+----------+--------------+------------------+-------------------+

默認狀況下，這兩個選項爲空，那麼這兩個參數有何做用？是否如同其字面意思一個只讓某個庫記錄 binglog 一個排除某個庫記錄 binlog 呢？筆者查閱官方文檔，簡單說明下這兩個參數的做用：

• binlog_do_db：此參數表示只記錄指定數據庫的二進制日誌，默認所有記錄。
• binlog_ignore_db：此參數表示不記錄指定的數據庫的二進制日誌。

這兩個參數爲互斥關係，通常只選擇其一設置，只能在啓動命令行中或配置文件中加入。指定多個數據庫要分行寫入，舉例以下：

# 指定 db1 db2 記錄binlog
[mysqld]
binlog_do_db = db1
binlog_do_db = db2

# 不讓 db3 db4 記錄binlog
[mysqld]
binlog_ignore_db = db3
binlog_ignore_db = db4

此外，這兩者參數具體做用與否還與 binlog 格式有關係，在某些狀況下 binlog 格式設置爲 STATEMENT 或 ROW 會有不一樣的效果。在實際應用中 binlog_ignore_db 用途更普遍些，好比說某個庫的數據不過重要，爲了減輕服務器寫入壓力，咱們可能不讓該庫記錄 binlog 。網上也有文章說設置 binlog_ignore_db 會致使從庫同步錯誤，那麼設置該參數到底有什麼效果呢，下面咱們來具體實驗下。

2. binlog_ignore_db 具體效果

首先說明下，個人測試數據庫實例是 5.7.23 社區版本，共有 testdb、logdb 兩個業務庫，咱們設置 logdb 不記錄 binlog ，下面來具體實驗下：

# binlog 爲 ROW 格式 

# 1.不使用 use db
mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |      154 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
mysql> select database();
+------------+
| database() |
+------------+
| NULL       |
+------------+
1 row in set (0.00 sec)
mysql> CREATE TABLE testdb.`test_tb1` ( id int , name varchar(30) ) ENGINE=InnoDB  DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.06 sec)

mysql> insert into testdb.test_tb1 values (1001,'sdfde');
Query OK, 1 row affected (0.01 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |      653 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> CREATE TABLE logdb.`log_tb1` ( id int , name varchar(30) ) ENGINE=InnoDB  DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.05 sec)

mysql> insert into logdb.log_tb1 values (1001,'sdfde');
Query OK, 1 row affected (0.00 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |      883 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
mysql> insert into logdb.log_tb1 values (1002,'sdsdfde'); 
Query OK, 1 row affected (0.01 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |      883 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+

mysql> alter table logdb.log_tb1 add column c3 varchar(20);   
Query OK, 0 rows affected (0.12 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     1070 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
# 結論：其餘庫記錄正常 logdb庫會記錄DDL 不記錄DML 

# 2.使用 use testdb跨庫
mysql> use testdb;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> select database();
+------------+
| database() |
+------------+
| testdb     |
+------------+
1 row in set (0.00 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     1070 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> CREATE TABLE `test_tb2` ( id int , name varchar(30) ) ENGINE=InnoDB  DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.05 sec)

mysql> insert into test_tb2 values (1001,'sdfde');
Query OK, 1 row affected (0.04 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     1574 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> CREATE TABLE logdb.`log_tb2` ( id int , name varchar(30) ) ENGINE=InnoDB  DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.05 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     1810 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> insert into logdb.log_tb2 values (1001,'sdfde');
Query OK, 1 row affected (0.01 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     1810 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
# 結論：一樣logdb庫會記錄DDL 不記錄DML 

# 3.使用 use logdb跨庫
mysql> use logdb;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> select database();
+------------+
| database() |
+------------+
| logdb      |
+------------+
1 row in set (0.00 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     1810 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> CREATE TABLE testdb.`test_tb3` ( id int , name varchar(30) ) ENGINE=InnoDB  DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.23 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     1810 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> insert into testdb.test_tb3 values (1001,'sdfde');
Query OK, 1 row affected (0.02 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     2081 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> CREATE TABLE `log_tb3` ( id int , name varchar(30) ) ENGINE=InnoDB  DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.05 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     2081 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> insert into log_tb3 values (1001,'sdfde');
Query OK, 1 row affected (0.02 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     2081 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
# 結論：logdb都不記錄 同時不記錄其餘庫的DDL

# 4.每次操做都進入此庫 不跨庫
mysql> use testdb;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     2081 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> CREATE TABLE `test_tb4` ( id int , name varchar(30) ) ENGINE=InnoDB  DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.05 sec)

mysql> insert into test_tb4 values (1001,'sdfde');
Query OK, 1 row affected (0.01 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     2585 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> use logdb;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> CREATE TABLE `log_tb4` ( id int , name varchar(30) ) ENGINE=InnoDB  DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.04 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     2585 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> insert into log_tb4 values (1001,'sdfde');
Query OK, 1 row affected (0.01 sec)

mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000011 |     2585 |              | logdb            |                   |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
# 結論：其餘庫所有記錄 logdb全不記錄

一樣的，將 binlog 格式設置爲 STATEMENT ，再次進行測試，這裏再也不贅述測試過程，總結下 STATEMENT 格式下的實驗結果：

• 未選擇任何數據庫進行操做，全部都會記錄。
• 選擇testdb，對testdb和logdb分別進行操做，全部庫都會記錄。
• 選擇logdb，對testdb和logdb分別進行操做，全部庫都不會記錄。
• 選擇某個庫並只對當前庫進行操做，則記錄正常，不會記錄logdb。

看了這麼多實驗數據，你是否眼花繚亂了呢，下面咱們以思惟導圖的形式總結以下：

這麼看來 binlog_ignore_db 參數的效果確實和諸多因素有關，特別是有從庫的狀況下，主庫要特別當心使用此參數，很容易產生主從同步錯誤。不過，按照嚴格標準只對當前數據庫進行操做，則不會產生問題。這也告訴咱們要嚴格按照標準來，只賦予業務帳號某個單庫的權限，也能避免各類問題發生。

總結：

不清楚各位讀者是否對這種介紹參數的文章感興趣呢？可能這些是數據庫運維人員比較關注的吧。本篇文章主要介紹關於 binlog 的 binlog_ignore_db 參數的具體做用，可能本篇文章實驗環境還不夠考慮周全，有興趣的同窗能夠參考下官方文檔，有助於對該參數有更深刻的瞭解。