TiDB System Tables

This document introduces TiDB system tables.

Grant system tables

These system tables contain grant information about user accounts and their privileges:

• user: user accounts, global privileges, and other non-privilege columns
• db: database-level privileges
• tables_priv: table-level privileges
• columns_priv: column-level privileges

Server-side help system tables

Currently, the help_topic is NULL.

Statistics system tables

• stats_buckets: the buckets of statistics
• stats_histograms: the histograms of statistics
• stats_meta: the meta information of tables, such as the total number of rows and updated rows

GC worker system tables

• gc_delete_range: to record the data to be deleted

Miscellaneous system tables

• GLOBAL_VARIABLES: global system variable table
• tidb: to record the version information when TiDB executes bootstrap