Item:print_for_table_def() uses QT_TO_SYSTEM_CHARSET to print
the DEFAULT expression into FRM file during CREATE TABLE.
Therefore, the expression is encoded in utf8 in FRM.
get_field_default_value() erroneously used field->charset() to
print the DEFAULT expression at SHOW CREATE TABLE time.
Fixing get_field_default_value() to use &my_charset_utf8mb4_general_ci instead.
This makes DEFAULT work in the way way with:
- virtual column expressions:
if (field->vcol_info)
{
StringBuffer<MAX_FIELD_WIDTH> str(&my_charset_utf8mb4_general_ci);
field->vcol_info->print(&str);
- check constraint expressions:
if (field->check_constraint)
{
StringBuffer<MAX_FIELD_WIDTH> str(&my_charset_utf8mb4_general_ci);
field->check_constraint->print(&str);
Additional cleanup:
Fixing system_charset_info to &my_charset_utf8mb4_general_ci in a few
places to make non-BMP characters work in DEFAULT, virtual column,
check constraint expressions.
safety first - tell mariadb client not to execute dangerous
cli commands, they cannot be present in the dump anyway.
wrapping the command in /*!999999 ..... */ guarantees that
if a non-mariadb-cli client loads the dump and sends it to the
server - the server will ignore the command it doesn't understand
With a global non-default max-statement-time of a time interval that exceed
the query time mysqldump queries when doing a backup.
To solve both, add a max-statement-time option, defaulting to 0 (unlimited time).
Also like mariabackup, set the session wait_timeout=DEFAULT (28800). The
time/processing between mysqldump times isn't expected to get that
close ever, but let's adopt the standard of mariabackup as no-one has
challenged it has having a detrimental effect.
Reviewer and test case author Daniel Black
