Problem:
=======
InnoDB allows virtual index to be referenced index in foreign key
relations. While dropping the virtual column, Inplace alter does
allow the table to be closed and open it using table name to
update dict_table_t::v_cols. While loading the table, it doesn't
allow any error to be ignored. InnoDB can't find the referenced
virtual index and fails to load the table during Inplace alter.
Solution:
=========
During inplace alter, ignore the foreign key error while loading
the table.
Reviewed-by: Marko Mäkelä
virtual column in index
Problem:
row_ins_foreign_fill_virtual was unconditionally set virtual fields to NULL
even though the field is not a part of a foreign key
(but a part of an index)
Solution:
The new virtual value should be computed with regard to cascade updates.
dict_foreign_qualify_index(): Avoid a redundant and harmful
computation of col_name of a virtual column. This fixes the
assertion failure.
dict_foreign_push_index_error(): Do not call dict_table_get_col_name()
on a virtual column. (It is unclear if this condition is actually
reachable.)
Analysis:
========
A foreign key constraint cannot reference a secondary index defined
on a generated virtual column. While adding new index/drop existing
column, server internally drops the internal foreign key index and
it leads to choose the virtual secondary index as foreign key index.
But innodb doesn't allow foreign key constraint reference to
secondary virtual index.
Fix:
===
Allow foreign key constraint refer to secondary index defined on
a generated virutal column.
Reviewed-by: Jimmy Yang<jimmy.yang@oracle.com>
RB: 13586
* remove old 5.2+ InnoDB support for virtual columns
* enable corresponding parts of the innodb-5.7 sources
* copy corresponding test cases from 5.7
* copy detailed Alter_inplace_info::HA_ALTER_FLAGS flags from 5.7
- and more detailed detection of changes in fill_alter_inplace_info()
* more "innodb compatibility hooks" in sql_class.cc to
- create/destroy/reset a THD (used by background purge threads)
- find a prelocked table by name
- open a table (from a background purge thread)
* different from 5.7:
- new service thread "thd_destructor_proxy" to make sure all THDs are
destroyed at the correct point in time during the server shutdown
- proper opening/closing of tables for vcol evaluations in
+ FK checks (use already opened prelocked tables)
+ purge threads (open the table, MDLock it, add it to tdc, close
when not needed)
- cache open tables in vc_templ
- avoid unnecessary allocations, reuse table->record[0] and table->s->default_values
- not needed in 5.7, because it overcalculates:
+ tell the server to calculate vcols for an on-going inline ADD INDEX
+ calculate vcols for correct error messages
* update other engines (mroonga/tokudb) accordingly
