Before commit 6112853cda in MySQL 4.1.1
introduced the parameter innodb_file_per_table, all InnoDB data was
written to the InnoDB system tablespace (often named ibdata1).
A serious design problem is that once the system tablespace has grown to
some size, it cannot shrink even if the data inside it has been deleted.
There are also other design problems, such as the server hang MDEV-29930
that should only be possible when using innodb_file_per_table=0 and
innodb_undo_tablespaces=0 (storing both tables and undo logs in the
InnoDB system tablespace).
The parameter innodb_change_buffering was deprecated
in commit b5852ffbee.
Starting with commit baf276e6d4
(MDEV-19229) the number of innodb_undo_tablespaces can be increased,
so that the undo logs can be moved out of the system tablespace
of an existing installation.
If all these things (tables, undo logs, and the change buffer) are
removed from the InnoDB system tablespace, the only variable-size
data structure inside it is the InnoDB data dictionary.
DDL operations on .ibd files was optimized in
commit 86dc7b4d4c (MDEV-24626).
That should have removed any thinkable performance advantage of
using innodb_file_per_table=0.
Since there should be no benefit of setting innodb_file_per_table=0,
the parameter should be deprecated. Starting with MySQL 5.6 and
MariaDB Server 10.0, the default value is innodb_file_per_table=1.
fil_delete_tablespace(): Remove the unused parameter drop_ahi,
and add the parameter if_exists=false. We want to suppress
error messages if we know that the tablespace has been discarded.
dict_table_rename_in_cache(): Pass the new parameter to
fil_delete_tablespace(), that is, do not complain about
missing tablespace if the tablespace has been discarded.
row_make_new_pathname(): Declare as static.
row_drop_table_for_mysql(): Tolerate !table->data_dir_path
when the tablespace has been discarded.
row_rename_table_for_mysql(): Skip part of the RENAME TABLE
when fil_space_get_first_path() returns NULL.
This is the MariaDB equivalent of fixing the MySQL 5.7 regression
Bug #26935001 ALTER TABLE AUTO_INCREMENT TRIES TO READ
INDEX FROM DISCARDED TABLESPACE
Oracle did not publish a test case, but it is easy to guess
based on the commit message. The MariaDB code is different
due to MDEV-6076 implementing persistent AUTO_INCREMENT.
commit_set_autoinc(): Report ER_TABLESPACE_DISCARDED if the
tablespace is missing.
prepare_inplace_alter_table_dict(): Avoid accessing a discarded
tablespace. (This avoids generating warnings in fil_space_acquire().)
