When you only need view structure, don't call handle_derived with
DT_CREATE and rely on its internal hackish check to skip DT_CREATE.
Because handle_derived is called from many different places,
and this internal hackish check is indiscriminative.
Instead, just don't ask handle_derived to do DT_CREATE
if you don't want it to do DT_CREATE.
When you only need view structure, don't call handle_derived with
DT_CREATE and rely on its internal hackish check to skip DT_CREATE.
Because handle_derived is called from many different places,
and this internal hackish check is indiscriminative.
Instead, just don't ask handle_derived to do DT_CREATE
if you don't want it to do DT_CREATE.
plugin variables in SET only locked the plugin till the end of the
statement. If SET with a plugin variable was prepared, it was possible
to uninstall the plugin before EXECUTE. Then EXECUTE would crash,
trying to resolve a now-invalid pointer to a disappeared variable.
Fix: keep plugins locked until the prepared statement is closed.
Follow-up patch for the bug MDEV-25197 that fixes missed restoring
of thd->cur_stmt on returning error code.
Developed by Dmitry Shulga.
This fixes up the merge d2e2d32933
and closes MDEV-25413.
A user connected to a server with an expired password
can't change password with the statement "SET password=..."
if this statement is run in PS mode. In mentioned use case a user
gets the error ER_MUST_CHANGE_PASSWORD on attempt to run
the statement PREPARE stmt FOR "SET password=...";
The reason of failure to reset password by a locked user using the
statement PREPARE stmt FOR "SET password=..." is that PS-related
statements are not listed among the commands allowed for execution
by a user with expired password. However, simple adding of PS-related
statements (PREPARE FOR/EXECUTE/DEALLOCATE PREPARE ) to the list of
statements allowed for execution by a locked user is not enough
to solve problems, since it opens the opportunity for a locked user
to execute any statement in the PS mode.
To exclude this opportunity, additional checking that the statement
being prepared for execution in PS-mode is the SET statement has to be added.
This extra checking has been added by this patch into the method
Prepared_statement::prepared() that executed on preparing any statement
for execution in PS-mode.
Running statements with SET STATEMENT FOR clause is handled incorrectly in
case the whole statement is executed in prepared statement mode.
For example, running of the following statement
SET STATEMENT sql_mode = 'NO_ENGINE_SUBSTITUTION' FOR CREATE TABLE t1 AS SELECT CONCAT('abc') AS c1;
results in different definition of the table t1 depending on whether
the statement is executed as a prepared or as a regular statement.
In first case the column c1 is defined as
`c1` varchar(3) DEFAULT NULL
in the last case the column c1 is defined as
`c1` varchar(3) NOT NULL
Different definition for the column c1 arise due to the fact that
a value of the data memeber Item_func_concat::maybe_null depends on
whether strict mode is on or off. Below is definition of the method
fix_fields() of the class Item_str_func that is base class for the
class Item_func_concat that is created on parsing the
SET STATEMENT FOR clause.
bool Item_str_func::fix_fields(THD *thd, Item **ref)
{
bool res= Item_func::fix_fields(thd, ref);
/*
In Item_str_func::check_well_formed_result() we may set null_value
flag on the same condition as in test() below.
*/
maybe_null= maybe_null || thd->is_strict_mode();
return res;
}
Although the clause SET STATEMENT sql_mode = 'NO_ENGINE_SUBSTITUTION' FOR
is parsed on PREPARE phase during processing of the prepared statement,
real setting of the sql_mode system variable is done on EXECUTION phase.
On the other hand, the method Item_str_func::fix_fields is called on PREPARE
phase. In result, thd->is_strict_mode() returns true during calling the method
Item_str_func::fix_fields(), the data member maybe_null is assigned the value
true and column c1 is defined as DEFAULT NULL.
To fix the issue the system variables listed in the SET STATEMENT FOR clause
are set at the beginning of handling the PREPARE phase just right before
calling the function check_prepared_statement() and their original values
restored immediate after return from this function.
Additionally, to avoid code duplication the source code used in the function
mysql_execute_command for setting variables, specified by SET STATEMENT
clause, were extracted to the standalone functions
run_set_statement_if_requested(). This new function is called from
the function mysql_execute_command() and the method
Prepared_statement::prepare().
The reason for the failure is that
thd->mdl_context.release_transactional_locks()
was called after commit & rollback even in cases where the current
transaction is still active.
For 10.2, 10.3 and 10.4 the fix is simple:
- Replace all calls to thd->mdl_context.release_transactional_locks() with
thd->release_transactional_locks(). The thd function will only call
the mdl_context function if there are no active transactional locks.
In 10.6 we will better fix where we will change the return value for
some trans_xxx() functions to indicate if transaction did close the
transaction or not. This will avoid the need of the indirect call.
Other things:
- trans_xa_commit() and trans_xa_rollback() will automatically
call release_transactional_locks() if the transaction is closed.
- We can't do that for the other functions as the caller of many of these
are doing additional work (like close_thread_tables) before calling
release_transactional_locks().
- Added missing abort_result_set() and missing DBUG_RETURN in
select_create::send_eof()
- Fixed wrong indentation in injector::transaction::commit()
Do not resend metadata, if metadata does not change between prepare and
execute of prepared statement, or between executes.
Currently, metadata of *every* prepared statement will be checksummed,
and change is detected once checksum changes.
This is not from ideal, performance-wise. The code for
better/faster detection of unchanged metadata, is already in place, but
currently disabled due to PS bugs, such as MDEV-23913.
- mysqlnd from PHP < 7.3
- mysql-connector-python any version
- mysql-connector-java any version
Relaxed check about garbage at the end of the packet in case of no parameters.
Added check for array binding.
Fixed test according to the new paradigm (allow junk at the end of the packet)
Prepared statements which were run over binary protocol crashed
a server if the statement did not have CF_PS_ARRAY_BINDING_OPTIMIZED
flag and the statement was executed in bulk mode and a BF abort occrurred.
This was because the bulk execution resulted in several statements without
calling wsrep_after_statement() between, which confused wsrep transaction
state tracking.
As a fix, call wsrep_after_statement() in bulk loop after each execution
if CF_PS_ARRAY_BINDING_OPTIMIZED is not set.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>
