InnoDB always keeps all tablespaces in the fil_system cache.
The fil_system.LRU is only for closing file handles; the
fil_space_t and fil_node_t for all data files will remain
in main memory. Between startup to shutdown, they can only be
created and removed by DDL statements. Therefore, we can
let dict_table_t::space point directly to the fil_space_t.
dict_table_t::space_id: A numeric tablespace ID for the corner cases
where we do not have a tablespace. The most prominent examples are
ALTER TABLE...DISCARD TABLESPACE or a missing or corrupted file.
There are a few functional differences; most notably:
(1) DROP TABLE will delete matching .ibd and .cfg files,
even if they were not attached to the data dictionary.
(2) Some error messages will report file names instead of numeric IDs.
There still are many functions that use numeric tablespace IDs instead
of fil_space_t*, and many functions could be converted to fil_space_t
member functions. Also, Tablespace and Datafile should be merged with
fil_space_t and fil_node_t. page_id_t and buf_page_get_gen() could use
fil_space_t& instead of a numeric ID, and after moving to a single
buffer pool (MDEV-15058), buf_pool_t::page_hash could be moved to
fil_space_t::page_hash.
FilSpace: Remove. Only few calls to fil_space_acquire() will remain,
and gradually they should be removed.
mtr_t::set_named_space_id(ulint): Renamed from set_named_space(),
to prevent accidental calls to this slower function. Very few
callers remain.
fseg_create(), fsp_reserve_free_extents(): Take fil_space_t*
as a parameter instead of a space_id.
fil_space_t::rename(): Wrapper for fil_rename_tablespace_check(),
fil_name_write_rename(), fil_rename_tablespace(). Mariabackup
passes the parameter log=false; InnoDB passes log=true.
dict_mem_table_create(): Take fil_space_t* instead of space_id
as parameter.
dict_process_sys_tables_rec_and_mtr_commit(): Replace the parameter
'status' with 'bool cached'.
dict_get_and_save_data_dir_path(): Avoid copying the fil_node_t::name.
fil_ibd_open(): Return the tablespace.
fil_space_t::set_imported(): Replaces fil_space_set_imported().
truncate_t: Change many member function parameters to fil_space_t*,
and remove page_size parameters.
row_truncate_prepare(): Merge to its only caller.
row_drop_table_from_cache(): Assert that the table is persistent.
dict_create_sys_indexes_tuple(): Write SYS_INDEXES.SPACE=FIL_NULL
if the tablespace has been discarded.
row_import_update_discarded_flag(): Remove a constant parameter.
fil_iterate(), fil_tablespace_iterate(): Replace os_file_read()
with os_file_read_no_error_handling().
os_file_read_func(), os_file_read_no_error_handling_func():
Do not retry partial reads. There used to be an infinite amount
of retries. Because InnoDB extends both data and log files upfront,
partial reads should be impossible during normal operation.
InnoDB in Debian uses utf8mb4 as default character set since
version 10.0.20-2. This leads to major pain due to keys longer
than 767 bytes.
MariaDB 10.2 (and MySQL 5.7) introduced the setting
innodb_default_row_format that is DYNAMIC by default. These
versions also changed the default values of the parameters
innodb_large_prefix=ON and innodb_file_format=Barracuda.
This would allow longer column index prefixes to be created.
The original purpose of these parameters was to allow InnoDB
to be downgraded to MySQL 5.1, which is long out of support.
Every InnoDB version since MySQL 5.5 does support operation
with the relaxed limits.
We backport the parameter innodb_default_row_format to
MariaDB 10.1, but we will keep its default value at COMPACT.
This allows MariaDB 10.1 to be configured so that CREATE TABLE
is less likely to encounter a problem with the limitation:
loose_innodb_large_prefix=ON
loose_innodb_default_row_format=DYNAMIC
(Note that the setting innodb_large_prefix was deprecated in
MariaDB 10.2 and removed in MariaDB 10.3.)
The only observable difference in the behaviour with the default
settings should be that ROW_FORMAT=DYNAMIC tables can be created
both in the system tablespace and in .ibd files, no matter what
innodb_file_format has been assigned to. Unlike MariaDB 10.2,
we are not changing the default value of innodb_file_format,
so ROW_FORMAT=COMPRESSED tables cannot be created without
changing the parameter.
