Move table open result processing to the caller
* st_schema_table::process_table doesn't have to check whether the table
was opened successfully
* It also doesn't have to check for a thd error and convert it to a warning
* This simplifies adding new tables into information_schema
* A callback still can output some info to a user in case of error. In
order to do this, I_S_EXTENDED_ERROR_HANDLING should be specified in
i_s_requested_object.
Two new information_schema views are added:
* PERIOD table -- columns TABLE_CATALOG, TABLE_SCHEMA, TABLE_NAME,
PERIOD_NAME, START_COLUMN_NAME, END_COLUMN_NAME.
* KEY_PERIOD_USAGE -- works similar to KEY_COLUMN_USAGE, but for periods.
Columns CONSTRAINT_CATALOG, CONSTRAINT_SCHEMA, CONSTRAINT_NAME,
TABLE_CATALOG, TABLE_SCHEMA, TABLE_NAME, PERIOD_NAME
Two new columns are added to the COLUMNS view:
IS_SYSTEM_TIME_PERIOD_START, IS_SYSTEM_TIME_PERIOD_END - contain YES/NO.
DROP DATABASE would internally execute DROP TABLE on every contained
table and finally remove the directory. In InnoDB, DROP TABLE is
sometimes executed in the background. The table would be renamed to
a name that starts with #sql. The existence of these files would
prevent DROP DATABASE from succeeding.
CREATE OR REPLACE DATABASE can internally execute DROP DATABASE if
the directory already exists. This could fail due to the InnoDB
background DROP TABLE, possibly due to some tables that were
leftovers from earlier tests.
