title | summary |
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mysql Schema |
Learn about the TiDB system tables. |
The mysql
schema contains TiDB system tables. The design is similar to the mysql
schema in MySQL, where tables such as mysql.user
can be edited directly. It also contains a number of tables which are extensions to MySQL.
These system tables contain grant information about user accounts and their privileges:
user
: user accounts, global privileges, and other non-privilege columnsdb
: database-level privilegestables_priv
: table-level privilegescolumns_priv
: column-level privilegesdefault_roles
: the default roles for a userglobal_grants
: dynamic privilegesglobal_priv
: the authentication information based on certificatesrole_edges
: the relationship between roles
Currently, the help_topic
is NULL.
stats_buckets
: the buckets of statisticsstats_histograms
: the histograms of statisticsstats_top_n
: the TopN of statisticsstats_meta
: the meta information of tables, such as the total number of rows and updated rowsstats_extended
: extended statistics, such as the order correlation between columnsstats_feedback
: the query feedback of statisticsstats_fm_sketch
: the FMSketch distribution of the histogram of the statistics columnanalyze_options
: the defaultanalyze
options for each tablecolumn_stats_usage
: the usage of column statisticsschema_index_usage
: the usage of indexesanalyze_jobs
: the ongoing statistics collection tasks and the history task records within the last 7 days
bind_info
: the binding information of execution planscapture_plan_baselines_blacklist
: the blocklist for the automatic binding of the execution plan
gc_delete_range
: the KV range to be deletedgc_delete_range_done
: the deleted KV range
GLOBAL_VARIABLES
: global system variable table
tidb
: to record the version information when TiDB executesbootstrap
expr_pushdown_blacklist
: the blocklist for expression pushdownopt_rule_blacklist
: the blocklist for logical optimization rulestable_cache_meta
: the metadata of cached tables