tidb2.1 升级 3.0问题

acuitong · 2020 年4 月 3 日 07:34

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【TiDB 版本】：2.1.10
【问题描述】：表结构
CREATE TABLE a (
id int(11) NOT NULL AUTO_INCREMENT COMMENT ‘id’,
test varchar(3000) CHARSET utf8 COLLATE utf8_bin DEFAULT ‘’
PRIMARY KEY (id),
KEY indx_test (test),
);

引用

对比

2.1.10: 创建此带有varchar(3000) 带索引的表结构没有任何问题
3.0.12: 创建此带有varchar(3000) 带索引的表结构与mysql相同会报 Specified key was too long; max key length is 3072 bytes

问题：在线上ansible 2.1.10 升级 3.0.12过程中会不会因为这个表结构的问题升级失败??

2.1.10升级3.0.12升级操作，还有其他需要注意的地方吗??

来了老弟 · 2020 年4 月 3 日 08:00

稍等，我看下

来了老弟 · 2020 年4 月 3 日 08:06

您好，

升级不会出错，升级时调整 ansible conf/tidb.yml max-index-length 参数。

github.com

pingcap/tidb-ansible/blob/e4c205731b9ca3e4884dc7d4660c0a8b23d553b2/conf/tidb.yml#L30


      
          # Set the memory quota for a query in bytes. Default: 32GB
          # mem-quota-query: 34359738368
          
          # Make "kill query" behavior compatible with MySQL. It's not recommend to
          # turn on this option when TiDB server is behind a proxy.
          # compatible-kill-query: false
          
          # check mb4 value in utf8 is used to control whether to check the mb4 characters when the charset is utf8.
          # check-mb4-value-in-utf8: true
          
          # max-index-length is used to deal with compatibility issues from v3.0.7 and previous version upgrades. It can only be in [3072, 3072*4].
          # max-index-length: 3072
          
          # alter-primary-key is used to control alter primary key feature. Default is false, indicate the alter primary key feature is disabled.
          # If it is true, we can add the primary key by "alter table". However, if a table already exists before the switch is turned true and
          # the data type of its primary key column is an integer, the primary key cannot be dropped.
          # alter-primary-key: false
          
          # server-version is used to change the version string of TiDB in the following scenarios:
          # 1. the server version returned by builtin-function `VERSION()`.
          # 2. the server version filled in handshake packets of MySQL Connection Protocol, see https://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::Handshake for more details.

注意事项可以参考下：

acuitong · 2020 年4 月 3 日 08:10

嗯，好的，谢谢，那有没有其它要注意的点，还是像以前一样直接升级就行

来了老弟 · 2020 年4 月 3 日 08:13

推荐下《TiDB in Action》：https://book.tidb.io/session1/chapter1/tidb-architecture.html

acuitong · 2020 年4 月 3 日 08:15

ok , 谢啦

来了老弟 · 2020 年4 月 3 日 08:15