faq/upgrade: update upgrade faq #1527
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bb7133
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Jun 27, 2019
dev/faq/upgrade.md
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| @@ -203,3 +203,7 @@ TiDB 在 v2.1.1 及之前版本中，如果 charset 是 UTF8，没有对 4-byte | |||
| # Disabled. | |||
| set @@session.tidb_check_mb4_value_in_utf8 = 0; | |||
| ``` | |||
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| - v2.1.7 及之后版本，如果对表和 column 的字符集没有严格的要求为 UTF8，也不想修改客户端代码去跳过 UTF8 检查或者手动修改 column 的 charset，可以在配置文件中把 `treat-old-version-utf8-as-utf8mb4` 打开，这个配置的作用是，把所有字符集为 UTF8 的表和 column 自动在转成 UTF8MB4 的 charset。这个转换是在 TiDB load schema 时在内存中把 UTF8 转成 UTF8MB4，不会对实际存储的数据做任何修改。所以在配置文件中关闭 `treat-old-version-utf8-as-utf8mb4`，重启 TiDB 后，以前字符集为 UTF8 的表和 column 的字符集任然还是 UTF8。 | |||
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| - v2.1.7 及之后版本，如果对表和 column 的字符集没有严格的要求为 UTF8，也不想修改客户端代码去跳过 UTF8 检查或者手动修改 column 的 charset，可以在配置文件中把 `treat-old-version-utf8-as-utf8mb4` 打开，这个配置的作用是，把所有字符集为 UTF8 的表和 column 自动在转成 UTF8MB4 的 charset。这个转换是在 TiDB load schema 时在内存中把 UTF8 转成 UTF8MB4，不会对实际存储的数据做任何修改。所以在配置文件中关闭 `treat-old-version-utf8-as-utf8mb4`，重启 TiDB 后，以前字符集为 UTF8 的表和 column 的字符集任然还是 UTF8。 | |
| - v2.1.7 及之后版本，如果对表和 column 的字符集没有严格的要求为 UTF8，也不想修改客户端代码去跳过 UTF8 检查或者手动修改 column 的 charset，可以在配置文件中把 `treat-old-version-utf8-as-utf8mb4` 打开，这个配置的作用是，把所有字符集为 UTF8 的表和 column 自动在转成 UTF8MB4 的 charset。这个转换是在 TiDB load schema 时在内存中把 UTF8 转成 UTF8MB4，不会对实际存储的数据做任何修改。在配置文件中关闭 `treat-old-version-utf8-as-utf8mb4` 并重启 TiDB 后，以前字符集为 UTF8 的表和 column 的字符集仍然还是 UTF8。 |
lilin90
reviewed
Jul 9, 2019
Co-Authored-By: Lilian Lee <lilin@pingcap.com>
Co-Authored-By: Lilian Lee <lilin@pingcap.com>
Co-Authored-By: Lilian Lee <lilin@pingcap.com>
Co-Authored-By: Lilian Lee <lilin@pingcap.com>
Co-Authored-By: Lilian Lee <lilin@pingcap.com>
Co-Authored-By: Lilian Lee <lilin@pingcap.com>
Co-Authored-By: Lilian Lee <lilin@pingcap.com>
Co-Authored-By: Lilian Lee <lilin@pingcap.com>
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What is changed, added or deleted?
faq/upgrade: update upgrade faq.
add doc for
treat-old-version-utf8-as-utf8mb4config.What is the related PR or file link(s)?
pingcap/tidb#9820
Which version does your change affect?
dev, v3.0, v2.1, v2.1-legacy
Checklist
TOC.mdtitlein metadataTOC.md