Anel Husakovic added a comment - 2021-03-05 07:28 bertrandop here is the fix https://github.com/an3l/server/commit/086b9167bcbea369bf2bae0843e0085123701d29 based on commit https://github.com/MariaDB/server/commit/043a3a0176e2#diff-f223b918b8e982bb3edaed26dc567ac653c0cf35f5ca624e2e3b664d4be5d49dR10333 which introduced it. Example of the test with the fix: worker[1] Using MTR_BUILD_THREAD 300, with reserved ports 16000..16019 INSTALL SONAME 'ha_connect'; CREATE TABLE t (f INT) ENGINE=CONNECT; Warnings: Warning 1105 No table_type. Will be set to DOS Warning 1105 No file name. Table will use t.dos show create table t; Table Create Table t CREATE TABLE `t` ( `f` int(11) DEFAULT NULL ) ENGINE=CONNECT DEFAULT CHARSET=latin1 ALTER TABLE t ENGINE InnoDB; show create table t; Table Create Table t CREATE TABLE `t` ( `f` int(11) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1 DROP TABLE t; CREATE TABLE t (f INT) ENGINE=CONNECT; Warnings: Warning 1105 No table_type. Will be set to DOS Warning 1105 No file name. Table will use t.dos Warning 1105 Default file /dev/shm/var_auto_p2EI/mysqld.1/data/./test/t.dos already exists show create table t; Table Create Table t CREATE TABLE `t` ( `f` int(11) DEFAULT NULL ) ENGINE=CONNECT DEFAULT CHARSET=latin1 ALTER TABLE t ENGINE Aria; show create table t; Table Create Table t CREATE TABLE `t` ( `f` int(11) DEFAULT NULL ) ENGINE=Aria DEFAULT CHARSET=latin1 PAGE_CHECKSUM=1 DROP TABLE t; CREATE TABLE t (f INT) ENGINE=CONNECT; Warnings: Warning 1105 No table_type. Will be set to DOS Warning 1105 No file name. Table will use t.dos Warning 1105 Default file /dev/shm/var_auto_p2EI/mysqld.1/data/./test/t.dos already exists show create table t; Table Create Table t CREATE TABLE `t` ( `f` int(11) DEFAULT NULL ) ENGINE=CONNECT DEFAULT CHARSET=latin1 ALTER TABLE t ENGINE MYISAM; show create table t; Table Create Table t CREATE TABLE `t` ( `f` int(11) DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 DROP TABLE t; UNINSTALL SONAME 'ha_connect'; main.anel 'innodb' [ pass ] 16 -------------------------------------------------------------------------- The servers were restarted 0 times Spent 0.016 of 1 seconds executing testcases   Completed: All 1 tests were successful. However there are failing tests in other suite with this fix. Failing test(s): main.log_tables main.mysqldump main.mysql_upgrade main.statistics main.partition_cache_innodb main.mysql_upgrade_view main.column_compression main.merge main.type_bit_innodb main.type_temporal_innodb Will assign monty to review and suggest how to proceed for 10.5 . Alternative could be to disable initialization of table_options in innobase ( https://github.com/MariaDB/server/blob/10.5/storage/innobase/handler/ha_innodb.cc#L3847)([~serg ] )? but with that there are other types of errors.

Michael Widenius added a comment - 2021-03-10 13:28 - edited o Answer Anel's question about two calls to quick_rm_table: When doing an alter table from one engine to another, we need two calls to quick_rm_table(). First is to delete just the .frm file of the #sql-backup table. This contains a backup of the original table definition. The second call is to delete the original table from the OLD engine. The difference compared to before and after "commit 043a3a0176" is that if the engine ios changed in alter table, we don't create a #sql-backup in the new engine but instead create directly the final name. For example, assume you do for an myisam table alter table t1 engine=aria; The files during alter table in the new code are: t1.MAI t1.MAD t1.frm t1.MYD t1.MYI #sql-backup-4b21-3.frm In the old code we would had: t1.frm t1.MYD t1.MYI #sql-backup-4b21-3.frm #sql-backup-4b21-3.MAI #sql-backup-4b21-3.MAD The new code avoids an extra rename (or move) of #sql-backup-4b21-3.MAI and #sql-backup-4b21-3.MAD to t1.MAI and t1.MAD. The problem with connect is that I had not anticipated that the engine would internally, as part of drop table, try to open the original .frm file. The fix is to ensure that we are using the old method with connect engine. This could probably be achieved by adding HA_REUSES_FILE_NAMES as ha_table_flag for connect. Inital testing suggests that this works. Now running a full test before pushing

Olivier Bertrand added a comment - 2021-03-10 13:59 The problem with connect is that I had not anticipated that the engine would internally, as part of drop table, try to open the original .frm file Most Connect tables don't need to do anything in that context. Only "inward" tables (the ones for which the data file were not specified at creation and has been by default made in the current database) must erase that file. To do this, they don't need to really "open" the frm but just to know what is the name of the file to delete. For this they need the Option structure retrieved from the share structure. The above bug is that when retrieving the pointer to the Option from the share structure, an invalid pointer is returned by version 10.5 (only?) causing the crash when used.

Michael Widenius added a comment - 2021-03-10 16:18 Pushed to 10.5

Anel Husakovic added a comment - 2021-03-11 11:30 Pushed with the patch https://github.com/MariaDB/server/commit/1799caa3a1305d21acaa37169e6b14307b4b5f08 thanks monty