前言

我們MySQL線上環(huán)境大部分使用的是5.7.18的版本，這個(gè)版本已修復(fù)了很多bug，但針對(duì)主從復(fù)制的bug還是有很多的，尤其是一些組復(fù)制、并行復(fù)制的bug尤為突出，在5.7.19版本有做相應(yīng)改善和修復(fù)。所以建議5.7.19之前的版本還是不要使用mgr和并發(fā)復(fù)制的功能，如使用建議升級(jí)至5.7.19（含）以后的版本。

我這里遇到的問題主要是莫名其妙的數(shù)據(jù)同步出現(xiàn)問題，無法執(zhí)行stop slave，數(shù)據(jù)不一致等現(xiàn)象，經(jīng)過查看發(fā)現(xiàn)是版本bug所致，所以對(duì)已上線的從庫關(guān)閉并發(fā)復(fù)制，對(duì)未上線的系統(tǒng)實(shí)行版本升級(jí)。此風(fēng)險(xiǎn)非常非常高，各位務(wù)必重視。

具體5.7.19修復(fù)的復(fù)制bug如下：

參考手冊(cè)：https://dev.mysql.com/doc/relnotes/mysql/5.7/en/news-5-7-19.html

References: See also: Bug #84107.

Replication: In the case of delayed initialization of the Group Replication plugin, deployed in single-primary mode, secondaries were able to get writes through an asynchronous replication channel, which is not allowed in normal initialization of the Group Replication plugin. (Bug #26314756)

Replication: With GTIDs generated for incident log events, MySQL error code 1590 (ER_SLAVE_INCIDENT) could not be skipped using the --slave-skip-errors=1590 startup option on a replication slave. (Bug #26266758)

Replication: A USE statement that followed a SET GTID_NEXT statement sometimes had no effect. (Bug #26128931)

Replication: Groups can now contain members running different server versions to enable you to do online upgrades of a replication group. The rules for combining members in a group with different versions are:

If you have a group with 8.0 members, you cannot add a 5.7 member

If you have a group with 5.7 members you can add a 8.0 member, but it remains in read-only mode. Writing to this member is dangerous while the group contains multiple server versions and should be avoided.

In a single-primary group, if the current primary leaves the group and a new primary must be elected, the primary is first chosen from the lower version members. If no lower version member is found, the primary is chosen from newer version members. (Bug #25876807)

Replication: When binlog_checksum=NONE was set on a MySQL server after startup, and then Group Replication was started, if an error occurred, the server remained in RECOVERING state and could not be shut down. (Bug #25793366, Bug #85667)

Replication: In a Group Replication setup where circular asynchronous replication was implemented between members of different replication groups, view change log events were repeatedly replicated between the groups with new generated GTIDs each time. The fix ensures that view change log events are ignored outside the named replication group where they occur, and never generate new GTIDs. (Bug #25674926)

References: See also: Bug #26049695, Bug #25928854, Bug #25721175.

Replication: When first starting the MySQL server following an installation from RPM, passwword validation plugin is activated by default (true only for RPM installations). If binary logging was already enabled at this time, the activation was logged, even though plugin activations should not be recorded in the binary log. (Bug #25672750)