This change takes into account a column's GENERATED ALWAYS AS
expression dependcy on sql_mode's PAD_CHAR_TO_FULL_LENGTH and
NO_UNSIGNED_SUBTRACTION flags.
Indexed virtual columns as well as persistent generated columns are
now not allowed to have such dependencies to avoid inconsistent data
or index files on sql_mode changes.
So an error is now returned in cases like this:
CREATE OR REPLACE TABLE t1
(
a CHAR(5),
v VARCHAR(5) AS (a) PERSISTENT -- CHAR->VARCHAR or CHAR->TEXT = ERROR
);
Functions RPAD() and RTRIM() can now remove dependency on
PAD_CHAR_TO_FULL_LENGTH. So this can be used instead:
CREATE OR REPLACE TABLE t1
(
a CHAR(5),
v VARCHAR(5) AS (RTRIM(a)) PERSISTENT
);
Note, unlike CHAR->VARCHAR and CHAR->TEXT this still works,
not RPAD(a) is needed:
CREATE OR REPLACE TABLE t1
(
a CHAR(5),
v CHAR(5) AS (a) PERSISTENT -- CHAR->CHAR is OK
);
More sql_mode flags may affect values of generated columns.
They will be addressed separately.
See comments in sql_mode.h for implementation details.
row_build_index_entry_low(): ext does not contain virtual columns.
row_upd_store_v_row(): Copy virtual column values
This is based on the following fix in MySQL 5.7.24:
commit 4ec2158bec73f1582501c4b3e3de250fed9edc9a
Author: Sachin Agarwal <sachin.z.agarwal@oracle.com>
Date: Fri Aug 24 14:44:13 2018 +0530
Bug #27968952 INNODB CRASH/CORRUPTION WITH TEXT PREFIX INDEXES
Problem:
There are two problems:
1. If there is one secondary index on extenally
stored column and another seconday index on virtual column (whose
base column is not externally stored). then while updating seconday
index on vitrual column, virtual column data is replaced by
externally stoared column.
2. In row update operation, node->row contains
shallow copy of virtual data fields. While building an update vector
containing all the fields to be modified, compute virtual column.
which may causes change in virtual data fields in node->row.
In both the above cases, while updating seconday index on virtual
column, couldn't find the row and hit an explicite assert inside
ROW_NOT_FOUND.
Fix:
1. Added check if column is virtual then its ext flag should be ZERO
and virtual column data will not be replaced by offset column data.
2. Deep copy of virtual data fields for node->row.
RB: #20382
Reviewed by : Jimmy.Yang@oracle.com
Merge a test case and a code change from MySQL 5.7.22.
There was no commit message, but a test case was included.
d3ec326bcd
There is no Bug 25899959 mentioned in the MySQL 8.0.11 history.
Based on the number, it should have been filed before August 2017.
Maybe it was initially fixed in a not-yet-public MySQL 9.0 branch?
The code change differs from MySQL 5.7, because the mbminmaxlen
were split in MariaDB in MDEV-7049.
The InnoDB background tasks can modify tables while LOCK TABLES...WRITE
is in effect. The purge of InnoDB history always worked like this in
MariaDB, but in MySQL 5.7 it sometimes yields to LOCK TABLES.
Also, make gcol.innodb_virtual_index run the purge for an UPDATE
before DROP TABLE is executed.
* 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
