blob/text/int length isn't accuracy in column metadata · pingcap/tidb#7465

2018-08-22T12:45:04.000Z

1. What did you do? connection tidb with `--column-type-info` ``` create table bitest(b blob(2)); select * from bitest; ``` 2. What did you expect to see? ``` Length: 255 ``` 3. What did you see instead? ``` Length: 8 ``` 4. What version of TiDB are you using (`tidb-server -V` or run `select tidb_version();` on TiDB)? ``` 2.0.6 ``` ref #7463

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描述

What did you do?

connection tidb with --column-type-info

create table bitest(b blob(2));
select * from bitest;

What did you expect to see?

Length:     255

What did you see instead?

Length:     8

What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

2.0.6

ref #7463

贡献者指南

技术栈: gosql
领域: databasebackend
议题类型: bug
难度: 3
预计时间: half day
活动状态: stale
清晰度: mostly clear
前置要求: Go programmingTiDB internals
新手友好度: 40
研究方向: Investigate how TiDB reports column length for blob/text types. Compare the expected length (255 for blob(2)) with actual (8). The issue references #7463, which may contain related context. Look at the server's column metadata handling, possibly in the session or protocol layer.