pingcap/tidb

[Enhancement] Show temp table info in `infomation_schema.tables`

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#41,686 opened on Feb 23, 2023

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Description

Enhancement

TiDB supports the 'local temporary table'(compatible with MySQL) and 'global temporary table'(from ANSI SQL standard). However, there is no temporary table information in information_schema.tables, it's not very easy to manage them.

So we would like to add both local temporary and global temporary tables in information_schema.tables. For TABLE_TYPE column, we show LOCAL TEMPORARY for a local temporary table, GLOBAL TEMPORARY for a global temporary table

Note: this is not compatible with MySQL.

  • MySQL only supports local temporary table, and they do not show local temporary table in information_schema.tables. Instead, it provides information_schema.INNODB_TEMP_TABLE_INFO.
  • We think it is fine because we follow the SQL standard.

Contributor guide

Research direction
Study the implementation of `information schema.tables` in TiDB, particularly the `infoschema` package. Understand how table types are determined and add logic to include temporary tables with `LOCAL TEMPORARY` or `GLOBAL TEMPORARY` as the `TABLE TYPE`. Refer to existing handlers for `LocalTemporaryTable` and `GlobalTemporaryTable`. Ensure changes are reflected in the `information schema` and test with relevant SQL queries.
Tech stack
go
Domain
backenddatabase
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GoSQLTiDB internals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40