Hi!
>>>>> "Paul" == Paul McCullagh <paul.mccullagh@stripped>
> writes:
Paul> Hi All,
Paul> I am having a bit of a problem fixing the following bug:
Paul> https://bugs.launchpad.net/pbxt/+bug/513012
Paul> The problem is that it leads to "nested statements".
Paul> In the test, we have a table called tb0_eng2 which contains a few rows:
Paul> create table tb0_eng2 (
Paul> i1 int NOT NULL auto_increment, primary key (i1),
Paul> f1 int,
Paul> f2 char (32)
Paul> );
Paul> insert into tb0_eng2 (f1,f2) values
Paul> (7, 'init_val'),
Paul> (14, 'init_val'),
Paul> (10, 'init_val'),
Paul> (14, 'init_val'),
Paul> (4, 'init_val');
Paul> One of the rows is being constantly updated, as follows:
Paul> update tb0_eng2 set f2='Update #$counter' where f1=10;
Paul> A trigger on tb0_eng2, does an INSERT on tb0_logs for every UPDATE on
Paul> tb0_eng2:
Paul> Create trigger tb0_eng2_upd after update on tb0_eng2
Paul> for each row
Paul> insert into tb0_logs (entry_dsc)
Paul> values (concat('Update row ', old.i1, ' ', old.f2, ' -> ',
Paul> new.f2));
Paul> So the INSERT statement is "nested" in the UPDATE statement.
Paul> My problem is that I need to detect the start and end of statements.
Paul> As far as I can tell (at least I have always assumed this) in this case:
Paul> ha_handler::start_stmt() is called for each table at the start of a
Paul> statement, and
Paul> ha_handler::reset() is called for each table at the end of each
Paul> statement.
Paul> It would be easy to tell the start and end of statements if these
Paul> functions were only called ONCE for each statement.
Paul> However, if multiple tables are involved in a statement (which is not
Paul> the case in the example above), then start_stmt() and reset() are
Paul> called multiple times for each statement.
Paul> So how do I know where the actual boundaries of the statements are?
Why not simply have a counter in your transaction object for how
start_stmt - reset(); When this is 0 then you know stmnt ended.
In Maria we count number of calls to external_lock() and when the sum
goes to 0 we know the transaction has ended.
Regards,
Monty
