ALTER TABLE ... ADD FOREIGN KEY may trigger assertion failure when
it has LOCK=EXCLUSIVE clause or concurrent FLUSH TABLES is being
executed.
In both cases being altered table is marked as flushed, which forces
subsequent attempt to open parent table to re-open. Which in turn is
not allowed while transaction is running.
Rather than opening parent table, just take appropriate MDL lock.
Also removed table_already_fk_prelocked() check: MDL itself has much
better methods to handle duplicate locks. E.g. the former won't acquire
MDL_SHARED_NO_WRITE if it already has MDL_SHARED_READ.
renaming columns in a CHECK constraint during ALTER TABLE
taints the original TABLE and requires m_need_reopen=1.
In this case, though, renaming was redundant, so just don't do it.
remove TABLE_SHARE::error_table_name() and TABLE_SHARE::orig_table_name
(that was allocated in a wrong memroot in this bug).
instead, simply set TABLE_SHARE::table_name correctly.
Analysis:
========
Increasing the length of the indexed varchar column is not an instant operation for
innodb.
Fix:
===
- Introduce the new handler flag 'Alter_inplace_info::ALTER_COLUMN_INDEX_LENGTH' to
indicate the index length differs due to change of column length changes.
- InnoDB makes the ALTER_COLUMN_INDEX_LENGTH flag as instant operation.
This is a port of Mysql fix.
commit 913071c0b16cc03e703308250d795bc381627e37
Author: Nisha Gopalakrishnan <nisha.gopalakrishnan@oracle.com>
Date: Wed May 30 14:54:46 2018 +0530
BUG#26848813: INDEXED COLUMN CAN'T BE CHANGED FROM VARCHAR(15)
TO VARCHAR(40) INSTANTANEOUSLY
Problem:
========
Server fails to notify the engine by not setting the ADD_PK_INDEX and
DROP_PK_INDEX When there is a
i) Change in candidate for primary key.
ii) New candidate for primary key.
Fix:
====
Server sets the ADD_PK_INDEX and DROP_PK_INDEX while doing alter for the
above problematic case.
The error message modified.
Then the TABLE_SHARE::error_table_name() implementation taken from 10.3,
to be used as a name of the table in this message.
Locked_tables_list::unlock_locked_tables
Similarly to regular DROP TABLE, don't leave locked tables mode if CREATE OR
REPLACE dropped temporary table but failed to cerate new one.
The problem is that there's no track of which temporary table was "locked" by
LOCK TABLES.
ALTER TABLE locks the table with TL_READ_NO_INSERT, to prevent the
source table modifications while it's being copied. But there's an
indirect way of modifying a table, via cascade FK actions.
After previous commits, an attempt to modify an FK parent table
will cause FK children to be prelocked, so the table-being-altered
cannot be modified by a cascade FK action, because ALTER holds a
lock and prelocking will wait.
But if a new FK is being added by this very ALTER, then the target
table is not locked yet (it's a temporary table). So, we have to
lock FK parents explicitly.
Problem was that the number of NULL bit's was record wrong in the
.frm file because there could be more fields marked NOT_NULL after the
number of not_null fields where recorded.
Fixed by copying test for virtual fields from prepare_create_field()
The code change, only the test, doesn't have to be merged to 10.3
as this is fixed there.
MEMORY table could be renamed into a non-extistent database.
rename() is documented to return ENOENT when the source file does not
exist OR when the target directory not exist. Nonexistent source .frm
file is ok (table can still exist in the engine), nonexistent target
directory is not.
Make my_rename to use ENOTDIR for the latter case. Make RENAME TABLE
issue an appropriate error ("unknown database" instead of "unknown table")
Crash happened because in discover, table->work_part_info was not properly
reset before execution.
Fixed by resetting before calling execute alter table, create table or
mysql_create_frm_image.
Crash happened when deleting all columns that was part of a check constraint
The bug was that read map for from table was used when
checking CHECK constraint and was not properly reset
in copy_data_between_tables()
Problem was that if copy_data_between_tables() didn't do proper
clean up in case of failures:
- copy object was not properly freed
- end_bulk_insert() was not called
- mysql_trans_prepare_alter_copy_data() set THD->transaction.on to
false which was not properly restored
The last part caused a crash in Aria as Aria depends on that THD
is correct.
Other things:
- Reset info->switched_transactional after usage (safety)
- Reset bulk_insert_single_undo (safety)
Part one, non-temporary tables.
Rrenaming a column can make destructive changes
to the TABLE. This TABLE cannot be used anymore
and needs to be reopened even if ALTER TABLE
was aborted with an error.
don't try to convert a default value string from a user character set
into a column character set, if this particular default value string did
not came from the user at all (that is, if it's an ALTER TABLE and the
default value string is the *old* default value of the unaltered
column).
This used to crash, because old defaults are allocated on the old
table's memroot, which is freed mid-ALTER when the old table is closed.
So thd->rollback_item_tree_changes() at the end of the ALTER was writing
into the freed memory.
