Marko Mäkelä added a comment - 2020-03-16 14:00 I am considering to use append and mapped instead of ‘add’ or ‘drop’. Here is the 10.3 version . The commit message includes some reasoning for these names.

Marko Mäkelä added a comment - 2020-03-18 08:58 - edited After some more discussions, I am suggesting the following names: --echo #do not allow MDEV-11369 instant ADD / MDEV-15562 instant DROP/reorder set global innodb_file_format=barracuda; --echo # ditto, and if instant ADD/DROP had been used in the past, ALTER TABLE would rebuild the table set global innodb_file_format=force_barracuda_compatible; --echo # do not allow MDEV-15562 instant DROP/redorder set global innodb_file_format=10_3; --echo # ditto, and any subsequent ALTER TABLE would rebuild to the requested format if needed set global innodb_file_format=force_10_3_compatible; --echo # allow instant ADD/DROP/reorder, but not possible future format changes set global innodb_file_format=10_4; --echo # same as 10_4, at least for now set global innodb_file_format=force_10_4_compatible; I would use _ instead of . so that quotes around the parameter values can be avoided. We might want to omit the force_…_compatible variants and always enforce the requested format in ALTER TABLE or OPTIMIZE TABLE . That could cause a negative surprise for users who might have a leftover innodb_file_format=barracuda in their configuration files and could have executed instant ADD/DROP in an earlier 10.3 or 10.4 version. However, they should have noticed the deprecation warning for that parameter. For future file format changes after MariaDB Server 10.5, we might introduce another parameter to control whether instant ADD/DROP is allowed, or we could introduce further values for innodb_file_format . In my vision, we could extend the 10.4 metadata record format with further things (persistent COUNT in MDEV-18188 , or secondary index metadata for simpler IMPORT in MDEV-11658 ), and users could want to use that format while preventing instant ADD/DROP/reorder column.

Marko Mäkelä added a comment - 2020-03-18 16:34 From the user point of view, the file format might be an uninteresting implementation detail. What the user wants is a guarantee that there will be no overhead for future DML operations. Instant ADD COLUMN or DROP COLUMN always incurs some of that. So, reviving the deprecated parameter innodb_file_format might be a bad idea, especially given the future plans to improve the .ibd file format in ways that have nothing to do with instant ALTER TABLE operations. I revise my suggestion to introduce a new parameter innodb_instant_alter_column_allowed : --echo #Do not allow MDEV-11369 instant ADD / MDEV-15562 instant DROP/reorder --echo #If a table already was in conflicting format, force a rebuild on any subsequent ALTER TABLE. --echo #Coincidentally, IMPORT TABLESPACE should work to any MariaDB 10.x version. SET GLOBAL innodb_instant_alter_column_allowed= no ; --echo #Do not allow MDEV-15562 instant DROP/reorder but do allow MDEV-11369 --echo #If a table already was in conflicting format, force a rebuild on any subsequent ALTER TABLE. SET GLOBAL innodb_instant_alter_column_allowed=add_last; --echo #Allow any instant ALTER TABLE. SET GLOBAL innodb_instant_alter_column_allowed=add_drop_reorder; The maximum and default values would be as follows: 10.3: innodb_instant_alter_column_allowed=add_last (other allowed values: no ) 10.4 and 10.5: innodb_instant_alter_column_allowed=add_drop_reorder (other allowed values: no , add_last )

Matthias Leich added a comment - 2020-03-19 18:20 Result of RQG testing with a derivate (additional SET GLOBAL innodb_file_format = <number>) of the grammar conf/mariadb/table_stress_innodb.yy on bb-10.4-MDEV-20590 commit 163dc5f919d3a8bf12288a8653d4c90e75809acc No new asserts or SEGV's

Marko Mäkelä added a comment - 2020-03-30 10:00 - edited I pushed this to 10.3 and merged up to 10.5. Starting with 10.3.24, we introduce the parameter with the default value add_last , and the non-default value never would introduce a constraint. Starting with MariaDB 10.4.14, 10.5.3, and later, we introduce the parameter with the default value will be add_drop_reorder . --echo #Do not allow MDEV-11369 instant ADD / MDEV-15562 instant DROP/reorder --echo #If a table already was in conflicting format, force a rebuild on any subsequent ALTER TABLE. --echo #Coincidentally, IMPORT TABLESPACE should work to any MariaDB 10.x version. SET GLOBAL innodb_instant_alter_column_allowed=never; --echo #Do not allow MDEV-15562 instant DROP/reorder but do allow MDEV-11369 --echo #If a table already was in conflicting format, force a rebuild on any subsequent ALTER TABLE. SET GLOBAL innodb_instant_alter_column_allowed=add_last; --echo #Allow any instant ALTER TABLE. SET GLOBAL innodb_instant_alter_column_allowed=add_drop_reorder;