Shorten some VARCHAR attributes to a more reasonable length.
INNODB_METRICS: Rename the column STATUS to ENABLED, and make it Boolean.
Replace with INT(1) many Boolean attributes that were declared as VARCHAR
containing 'NO','YES','disabled','enabled','Uninitialized','Initialized'.
Replace some VARCHAR attributes with ENUM.
Replace some BIGINT with INT when 32 bits are sufficient.
Remove INNODB_SYS_TABLESPACES.SPACE_TYPE. The type of a tablespace
can be derived from the tablespace ID. A fixed number is used for
the system tablespace and the temporary tablespace. All other tablespaces
are single-table or single-partition tablespaces.
i_s_locks_row_t::lock_type, lock_get_type_str(): Remove.
This is a redundant field. Table and record locks can be
distinguished by whether i_s_locks_row_t::lock_index is NULL.
fill_trx_row(): Do not unnecessarily copy the constant strings that
trx->op_info is pointing to.
i_s_locks_row_t::lock_mode: Replace string with integer.
lock_get_mode_str(), lock_get_trx_id(), lock_get_trx(): Remove.
field_store_ulint(): Remove.
MySQL 5.7 introduced WL#7943: InnoDB: Implement Information_Schema.Files
to provide a long-term alternative for accessing tablespace metadata.
The INFORMATION_SCHEMA.INNODB_* views are considered internal interfaces
that are subject to change or removal between releases. So, users should
refer to I_S.FILES instead of I_S.INNODB_SYS_TABLESPACES to fetch metadata
about CREATE TABLESPACE.
Because MariaDB 10.2 does not support CREATE TABLESPACE or
CREATE TABLE…TABLESPACE for InnoDB, it does not make sense to support
I_S.FILES either. So, let MariaDB 10.2 omit the code that was added in
MySQL 5.7. After this change, I_S.FILES will report the empty result,
unless some other storage engine in MariaDB 10.2 implements the interface.
(The I_S.FILES interface was originally created for the NDB Cluster.)
