mysqldump關於--set-gtid-purged=OFF的使用

數據庫的模式中我開啓了gtid：

mysql> show variables like '%gtid%';

+----------------------------------+-----------+

| Variable_name | Value |

+----------------------------------+-----------+

| binlog_gtid_simple_recovery | ON |

| enforce_gtid_consistency | ON |

| gtid_executed_compression_period | 1000 |

| gtid_mode | ON |

| gtid_next | AUTOMATIC |

| gtid_owned | |

| gtid_purged | |

| session_track_gtids | OFF |

+----------------------------------+-----------+

我如今數據庫中有一world的庫，而且在庫中有一個country表，如今進行備份時會提示以下警告：

[root@smiletest data]# mysqldump -uroot -p -R -e --triggers --master-data=2 --single-transaction world country >/tmp/countryno.sql

Enter password:

Warning: A partial dump from a server that has GTIDs will by default include the GTIDs of all transactions, even those that changed suppressed parts of the database. If you don't want to restore GTIDs, pass --set-gtid-purged=OFF. To make a complete dump, pass --all-databases --triggers --routines --events.

咱們來對比下加了 --set-gtid-purged=OFF和不加的區別

countryno.sql是沒有加--set-gtid-purged=OFF

[root@smiletest data]# mysqldump -uroot -p -R -e --triggers --master-data=2 --single-transaction world country >/tmp/countryno.sql

countryyes.sql是加--set-gtid-purged=OFF

[root@smiletest data]# mysqldump -uroot -p -R -e --triggers --master-data=2 --single-transaction --set-gtid-purged=OFF world country >/tmp/countryyes.sql

Enter password:

沒有加 --set-gtid-purged=OFF 的裏面會多幾條語句

SET @MYSQLDUMP_TEMP_LOG_BIN = @@SESSION.SQL_LOG_BIN;

SET @@SESSION.SQL_LOG_BIN= 0;

-- GTID state at the beginning of the backup

SET @@GLOBAL.GTID_PURGED='e024c334-8b64-11e9-80dc-fa163e4bfc29:1-761734';

如今咱們進行導入剛沒有加--set-gtid-purged=OFF備份的/tmp/countryno.sql語句

mysql> show master status;

+------------------+----------+--------------+------------------+-----------------------------------------------+

| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |

+------------------+----------+--------------+------------------+-----------------------------------------------+

| mysql-bin.000013 | 85019 | | | e024c334-8b64-11e9-80dc-fa163e4bfc29: 1-761735 |

+------------------+----------+--------------+------------------+-----------------------------------------------+

1 row in set (0.00 sec)

mysql> source /tmp/countryno.sql

Query OK, 0 rows affected (0.00 sec)

mysql> show master status;

+------------------+----------+--------------+------------------+-----------------------------------------------+

| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |

+------------------+----------+--------------+------------------+-----------------------------------------------+

| mysql-bin.000013 | 85019 | | | e024c334-8b64-11e9-80dc-fa163e4bfc29:1- 761735 |

+------------------+----------+--------------+------------------+-----------------------------------------------+

1 row in set (0.00 sec)

結論發現，gtid事務和 Position都沒有增長

如今咱們進行導入剛加--set-gtid-purged=OFF備份的/tmp/countryyes.sql語句

mysql> drop table country;

Query OK, 0 rows affected (0.01 sec)

mysql> show master status;

+------------------+----------+--------------+------------------+-----------------------------------------------+

| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |

+------------------+----------+--------------+------------------+-----------------------------------------------+

| mysql-bin.000013 | 112669 | | | e024c334-8b64-11e9-80dc-fa163e4bfc29:1- 761742 |

+------------------+----------+--------------+------------------+-----------------------------------------------+

1 row in set (0.00 sec)

mysql> source /tmp/countryyes.sql

Query OK, 0 rows affected (0.00 sec)

mysql> show master status;

+------------------+----------+--------------+------------------+-----------------------------------------------+

| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |

+------------------+----------+--------------+------------------+-----------------------------------------------+

| mysql-bin.000013 | 139929 | | | e024c334-8b64-11e9-80dc-fa163e4bfc29:1- 761747 |

+------------------+----------+--------------+------------------+-----------------------------------------------+

1 row in set (0.00 sec)

mysql>

結論發現，gtid事務和 Position都增長了

結論

加了--set-gtid-purged=OFF時，在會記錄binlog日誌，若是不加，不記錄binlog日誌，因此在咱們作主從用了gtid時，用mysqldump備份時就要加--set-gtid-purged=OFF，不然你在主上導入恢復了數據，主沒有了binlog日誌，同步則不會被同步。