MySQL Server supports a
statement that returns information from the MySQL Reference Manual
(see Section 13.8.3, “HELP Syntax”). This information is stored in
several tables in the
mysql schema (see
Section 5.3, “The mysql System Schema”). Proper operation of the
HELP statement requires that these
help tables be initialized.
For a new installation of MySQL using a binary or source distribution on Unix, help-table content initialization occurs when you initialize the data directory (see Section 2.10.1, “Initializing the Data Directory”). For an RPM distribution on Linux or binary distribution on Windows, content initialization occurs as part of the MySQL installation process.
For a MySQL upgrade using a binary distribution, help-table
content is upgraded automatically by the server as of MySQL
8.0.16. Prior to MySQL 8.0.16, the content is not upgraded
automatically, but you can upgrade it manually. Locate the
fill_help_tables.sql file in the
directory. Change location into that directory and process the
file with the mysql client as follows:
mysql -u root -p mysql < fill_help_tables.sql
The command shown here assumes that you connect to the server
using an account such as
root that has
privileges for modifying tables in the
schema. Adjust the connection parameters as required.
Prior to MySQL 8.0.16, if you are working with Git and a MySQL
development source tree, the source tree contains only a
“stub” version of
fill_help_tables.sql. To obtain a non-stub
copy, use one from a source or binary distribution.
Each MySQL series has its own series-specific reference manual, so help-table content is series specific as well. This has implications for replication because help-table content should match the MySQL series. If you load MySQL 8.0 help content into a MySQL 8.0 master server, it does not make sense to replicate that content to a slave server from a different MySQL series and for which that content is not appropriate. For this reason, as you upgrade individual servers in a replication scenario, you should upgrade each server's help tables, using the instructions given earlier. (Manual help-content upgrade is necessary only for replication servers from versions lower than 8.0.16. As mentioned in the preceding instructions, content upgrades occur automatically as of MySQL 8.0.16.)