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MySQL binlog_ignore_db 引數最全解析

前言:

經過前面文章學習,我們知道 binlog 會記錄資料庫所有執行的 DDL 和 DML 語句(除了資料查詢語句select、show等)。注意預設情況下會記錄所有庫的操作,那麼如果我們有另類需求,比如說只讓某個庫記錄 binglog 或排除某個庫記錄 binlog ,是否支援此類需求呢?本篇文章我們一起來看下。

1. binlog_do_db 與 binlog_ignore_db

當資料庫例項開啟 binlog 時,我們執行 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 |              |                  |                   |
+---------------+----------+--------------+------------------+-------------------+

預設情況下,這兩個選項為空,那麼這兩個引數有何作用?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?筆者查閱官方文件,簡單說明下這兩個引數的作用:

  • binlog_do_db:此引數表示只記錄指定資料庫的二進位制日誌,預設全部記錄。
  • binlog_ignore_db:此引數表示不記錄指定的資料庫的二進位制日誌。

這兩個引數為互斥關係,一般只選擇其一設定,只能在啟動命令列中或配置檔案中加入。指定多個數據庫要分行寫入,舉例如下:

# 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,這二者引數具體作用與否還與 binlog 格式有關係,在某些情況下 binlog 格式設定為 STATEMENT 或 ROW 會有不同的效果。在實際應用中 binlog_ignore_db 用途更廣泛些,比如說某個庫的資料不太重要,為了減輕伺服器寫入壓力,我們可能不讓該庫記錄 binlog 。網上也有文章說設定 binlog_ignore_db 會導致從庫同步錯誤,那麼設定該引數到底有什麼效果呢,下面我們來具體實驗下。

2. binlog_ignore_db 具體效果

首先說明下,我的測試資料庫例項是 5.7.23 社群版本,共有 testdb、logdb 兩個業務庫,我們設定 logdb 不記錄 binlog ,下面來具體實驗下:

# binlog 為 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:其他庫記錄正常 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:同樣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 同時不記錄其他庫的DDL

# 4.每次操作都進入此庫 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:其他庫全部記錄 logdb全不記錄

同樣的,將 binlog 格式設定為 STATEMENT ,再次進行測試,這裡不再贅述測試過程,總結下 STATEMENT 格式下的實驗結果:

  • 未選擇任何資料庫進行操作,所有都會記錄。
  • 選擇testdb,對testdb和logdb分別進行操作,所有庫都會記錄。
  • 選擇logdb,對testdb和logdb分別進行操作,所有庫都不會記錄。
  • 選擇某個庫並只對當前庫進行操作,則記錄正常,不會記錄logdb。

看了這麼多實驗資料,你是否眼花繚亂了呢,下面我們以思維導圖的形式總結如下:

這麼看來 binlog_ignore_db 引數的效果確實和諸多因素有關,特別是有從庫的情況下,主庫要特別小心使用此引數,很容易產生主從同步錯誤。不過,按照嚴格標準只對當前資料庫進行操作,則不會產生問題。這也告訴我們要嚴格按照標準來,只賦予業務賬號某個單庫的許可權,也能避免各種問題發生。

總結:

不清楚各位讀者是否對這種介紹引數的文章感興趣呢?可能這些是資料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 引數的具體作用,可能本篇文章實驗環境還不夠考慮周全,有興趣的同學可以參考下官方文件,有助於對該引數有更深入的瞭解。