causes future shutdown hang
InnoDB would hang on shutdown if any XA transactions exist in the
system in the PREPARED state. This has been masked by the fact that
MySQL would roll back any PREPARED transaction on shutdown, in the
spirit of Bug #12161 Xa recovery and client disconnection.
[mysql-test-run] do_shutdown_server: Interpret --shutdown_server 0 as
a request to kill the server immediately without initiating a
shutdown procedure.
xid_cache_insert(): Initialize XID_STATE::rm_error in order to avoid a
bogus error message on XA ROLLBACK of a recovered PREPARED transaction.
innobase_commit_by_xid(), innobase_rollback_by_xid(): Free the InnoDB
transaction object after rolling back a PREPARED transaction.
trx_get_trx_by_xid(): Only consider transactions whose
trx->is_prepared flag is set. The MySQL layer seems to prevent
attempts to roll back connected transactions that are in the PREPARED
state from another connection, but it is better to play it safe. The
is_prepared flag was introduced in the InnoDB Plugin.
trx_n_prepared: A new counter, counting the number of InnoDB
transactions in the PREPARED state.
logs_empty_and_mark_files_at_shutdown(): On shutdown, allow
trx_n_prepared transactions to exist in the system.
trx_undo_free_prepared(), trx_free_prepared(): New functions, to free
the memory objects of PREPARED transactions on shutdown. This is not
needed in the built-in InnoDB, because it would collect all allocated
memory on shutdown. The InnoDB Plugin needs this because of
innodb_use_sys_malloc.
trx_sys_close(): Invoke trx_free_prepared() on all remaining
transactions.
Bug#59410 read uncommitted: unlock row could not find a 3 mode lock
on the record
This bug is present only in 5.6 but I am adding the test case to earlier
versions to ensure it never appears in earlier versions too.
Setting lowercase_table_names to 2 on Windows causing Foreign Key problems
This problem was exposed by the fix for Bug#55222. There was a codepath in dict0load.c,
dict_load_foreigns() that made sure the table name matched case sensitive in order to
load a referenced table into the dictionary as needed. If an engine is rebooted which
accesses a table with foreign keys, and lower_case_table_names=2, then the table with
foreign keys will get an error when it is changed (insert/updated/delete).
Once the referenced tables are loaded into the dictionary cache by a select statement
on those tables, the same change would succeed because the affected code path would
not get followed.
"rows examined" estimates". This change implements "innodb_stats_method"
with options of "nulls_equal", "nulls_unequal" and "null_ignored".
rb://553 approved by Marko
- Second scenario checked:
Ensure via wait routines that the commit comes after the
processing of the statement which should get finally
the ER_LOCK_WAIT_TIMEOUT
--> This should prevent the current bug.
- First scenario checked:
Ensure via wait routines that the statement is already waiting
for getting the lock before the commit is given.
--> No effect on the current bug, but ensure that the right
scenario is reached.
- Take care that disconnects are finished before the test ends.
--> Reduce the potential to harm succeeding tests.
- "Mangle" the printout of the current default innodb_lock_wait_timeout value
--> No need to adjust the test in case the default gets changed in future.
--Bug#52157 various crashes and assertions with multi-table update, stored function
--Bug#54475 improper error handling causes cascading crashing failures in innodb/ndb
--Bug#57703 create view cause Assertion failed: 0, file .\item_subselect.cc, line 846
--Bug#57352 valgrind warnings when creating view
--Recently discovered problem when a nested materialized derived table is used
before being populated and it leads to incorrect result
We have several modes when we should disable subquery evaluation.
The reasons for disabling are different. It could be
uselessness of the evaluation as in case of 'CREATE VIEW'
or 'PREPARE stmt', or we should disable subquery evaluation
if tables are not locked yet as it happens in bug#54475, or
too early evaluation of subqueries can lead to wrong result
as it happened in Bug#19077.
Main problem is that if subquery items are treated as const
they are evaluated in ::fix_fields(), ::fix_length_and_dec()
of the parental items as a lot of these methods have
Item::val_...() calls inside.
We have to make subqueries non-const to prevent unnecessary
subquery evaluation. At the moment we have different methods
for this. Here is a list of these modes:
1. PREPARE stmt;
We use UNCACHEABLE_PREPARE flag.
It is set during parsing in sql_parse.cc, mysql_new_select() for
each SELECT_LEX object and cleared at the end of PREPARE in
sql_prepare.cc, init_stmt_after_parse(). If this flag is set
subquery becomes non-const and evaluation does not happen.
2. CREATE|ALTER VIEW, SHOW CREATE VIEW, I_S tables which
process FRM files
We use LEX::view_prepare_mode field. We set it before
view preparation and check this flag in
::fix_fields(), ::fix_length_and_dec().
Some bugs are fixed using this approach,
some are not(Bug#57352, Bug#57703). The problem here is
that we have a lot of ::fix_fields(), ::fix_length_and_dec()
where we use Item::val_...() calls for const items.
3. Derived tables with subquery = wrong result(Bug19077)
The reason of this bug is too early subquery evaluation.
It was fixed by adding Item::with_subselect field
The check of this field in appropriate places prevents
const item evaluation if the item have subquery.
The fix for Bug19077 fixes only the problem with
convert_constant_item() function and does not cover
other places(::fix_fields(), ::fix_length_and_dec() again)
where subqueries could be evaluated.
Example:
CREATE TABLE t1 (i INT, j BIGINT);
INSERT INTO t1 VALUES (1, 2), (2, 2), (3, 2);
SELECT * FROM (SELECT MIN(i) FROM t1
WHERE j = SUBSTRING('12', (SELECT * FROM (SELECT MIN(j) FROM t1) t2))) t3;
DROP TABLE t1;
4. Derived tables with subquery where subquery
is evaluated before table locking(Bug#54475, Bug#52157)
Suggested solution is following:
-Introduce new field LEX::context_analysis_only with the following
possible flags:
#define CONTEXT_ANALYSIS_ONLY_PREPARE 1
#define CONTEXT_ANALYSIS_ONLY_VIEW 2
#define CONTEXT_ANALYSIS_ONLY_DERIVED 4
-Set/clean these flags when we perform
context analysis operation
-Item_subselect::const_item() returns
result depending on LEX::context_analysis_only.
If context_analysis_only is set then we return
FALSE that means that subquery is non-const.
As all subquery types are wrapped by Item_subselect
it allow as to make subquery non-const when
it's necessary.
Auto increment value wraps when performing a bulk insert with
auto_increment_increment and auto_increment_offset greater than
one.
The fix:
If overflow happened then return MAX_ULONGLONG value as an
indication of overflow and check this before storing the
value into the field in update_auto_increment().
InnoDB does not attempt to handle lower_case_table_names == 2 when looking
up foreign table names and referenced table name. It turned that server
variable into a boolean and ignored the possibility of it being '2'.
The setting lower_case_table_names == 2 means that it should be stored and
displayed in mixed case as given, but compared internally in lower case.
Normally the server deals with this since it stores table names. But
InnoDB stores referential constraints for the server, so it needs to keep
track of both lower case and given names.
This solution creates two table name pointers for each foreign and referenced
table name. One to display the name, and one to look it up. Both pointers
point to the same allocated string unless this setting is 2. So the overhead
added is not too much.
Two functions are created in dict0mem.c to populate the ..._lookup versions
of these pointers. Both dict_mem_foreign_table_name_lookup_set() and
dict_mem_referenced_table_name_lookup_set() are called 5 times each.
