"Trigger fired multiple times leads to gaps in auto_increment sequence".
The bug was that if a trigger fired multiple times inside a top
statement (for example top-statement is a multi-row INSERT,
and trigger is ON INSERT), and that trigger inserted into an auto_increment
column, then gaps could be observed in the auto_increment sequence,
even if there were no other users of the database (no concurrency).
It was wrong usage of THD::auto_inc_intervals_in_cur_stmt_for_binlog.
Note that the fix changes "class handler", I'll tell the Storage Engine API team.
mysql-test/r/trigger-trans.result:
result; before the bugfix, the sequence was 1,2,4,6,8,10,12...
mysql-test/t/trigger-trans.test:
test for BUG#31612
sql/handler.cc:
See revision comment of handler.h.
As THD::auto_inc_intervals_in_cur_stmt_for_binlog is cumulative
over all trigger invokations by the top statement, the
second invokation of the trigger arrived in handler::update_auto_increment()
with already one interval in
THD::auto_inc_intervals_in_cur_stmt_for_binlog. The method thus
believed it had already reserved one interval for that invokation,
thus reserved a twice larger interval (heuristic when we don't know
how large the interval should be: we grow by powers of two). InnoDB
thus increased its internal per-table auto_increment counter by 2
while only one row was to be inserted. Hence a gap in the sequence.
The fix is to use the new handler::auto_inc_intervals_count.
Note that the trigger's statement knows how many rows it is going
to insert, but provides estimation_rows_to_insert == 0 (see comments
in sql_insert.cc why triggers don't call handler::ha_start_bulk_insert()).
* removing white space at end of line
* we don't need to maintain THD::auto_inc_intervals_in_cur_stmt_for_binlog
if no binlogging or if row-based binlogging. Using auto_inc_intervals_count in
the heuristic makes the heuristic independent of binary logging, which is good.
sql/handler.h:
THD::auto_inc_intervals_in_cur_stmt_for_binlog served
- for binlogging
- as a heuristic when we have no estimation of how many records the
statement will insert.
But the first goal needs to be cumulative over all statements which
form a binlog event, while the second one needs to be attached to each
statement. THD::auto_inc_intervals_in_cur_stmt_for_binlog is cumulative,
leading to BUG#31612. So we introduce handler::auto_inc_intervals_count
for the second goal. See the revision comment of handler.cc.
A smaller issue was that, even when the binlog event was only one
statement (no triggers, no stored functions),
THD::auto_inc_intervals_in_cur_stmt.nb_elements() could be lower than
the number of reserved intervals (fooling the heuristic), because its
append() method collapses two contiguous intervals in one.
Note that as auto_inc_intervals_count is in class 'handler' and not
in class 'THD', it does not need to be handled in
THD::reset|restore_sub_statement_state().
sql/log.cc:
Comment is wrong: if auto_increment is second, in handler::update_auto_increment()
'append' is false and so auto_inc_intervals_in_cur_stmt_for_binlog
is empty, we do not come here.
sql/sql_class.h:
comment
In cases when TRUNCATE was executed by invoking mysql_delete() rather
than by table recreation (for example, when TRUNCATE was issued on
InnoDB table with is referenced by foreign key) triggers were invoked.
In debug builds this also led to crash because of an assertion, which
assumes that some preliminary actions take place before trigger
invocation, which doesn't happen in case of TRUNCATE.
The fix is not to execute triggers in mysql_delete() when this
function is used by TRUNCATE.
mysql-test/r/trigger-trans.result:
Update result file.
mysql-test/t/trigger-trans.test:
A test case for Bug#34643: TRUNCATE crash if trigger and foreign key.
sql/sql_delete.cc:
Do not process triggers in TRUNCATE.
causes full table lock on innodb table.
Also fixes Bug#28502 Triggers that update another innodb table
will block on X lock unnecessarily (duplciate).
Code review fixes.
Both bugs' synopses are misleading: InnoDB table is
not X locked. The statements, however, cannot proceed concurrently,
but this happens due to lock conflicts for tables used in triggers,
not for the InnoDB table.
If a user had an InnoDB table, and two triggers, AFTER UPDATE and
AFTER INSERT, competing for different resources (e.g. two distinct
MyISAM tables), then these two triggers would not be able to execute
concurrently. Moreover, INSERTS/UPDATES of the InnoDB table would
not be able to run concurrently.
The problem had other side-effects (see respective bug reports).
This behavior was a consequence of a shortcoming of the pre-locking
algorithm, which would not distinguish between different DML operations
(e.g. INSERT and DELETE) and pre-lock all the tables
that are used by any trigger defined on the subject table.
The idea of the fix is to extend the pre-locking algorithm to keep track,
for each table, what DML operation it is used for and not
load triggers that are known to never be fired.
mysql-test/r/trigger-trans.result:
Update results (Bug#26141)
mysql-test/r/trigger.result:
Update results (Bug#28502)
mysql-test/t/trigger-trans.test:
Add a test case for Bug#26141 mixing table types in trigger causes
full table lock on innodb table.
mysql-test/t/trigger.test:
Add a test case for Bug#28502 Triggers that update another innodb
table will block echo on X lock unnecessarily. Add more test
coverage for triggers.
sql/item.h:
enum trg_event_type is needed in table.h
sql/sp.cc:
Take into account table_list->trg_event_map when determining
what tables to pre-lock.
After this change, if we attempt to fire a
trigger for which we had not pre-locked any tables, error
'Table was not locked with LOCK TABLES' will be printed.
This, however, should never happen, provided the pre-locking
algorithm has no programming bugs.
Previously a trigger key in the sroutines hash was based on the name
of the table the trigger belongs to. This was possible because we would
always add to the pre-locking list all the triggers defined for a table when
handling this table.
Now the key is based on the name of the trigger, owing
to the fact that a trigger name must be unique in the database it
belongs to.
sql/sp_head.cc:
Generate sroutines hash key in init_spname(). This is a convenient
place since there we have all the necessary information and can
avoid an extra alloc.
Maintain and merge trg_event_map when adding and merging elements
of the pre-locking list.
sql/sp_head.h:
Add ,m_sroutines_key member, used when inserting the sphead for a
trigger into the cache of routines used by a statement.
Previously the key was based on the table name the trigger belonged
to, since for a given table we would add to the sroutines list
all the triggers defined on it.
sql/sql_lex.cc:
Introduce a new lex step: set_trg_event_type_for_tables().
It is called when we have finished parsing but before opening
and locking tables. Now this step is used to evaluate for each
TABLE_LIST instance which INSERT/UPDATE/DELETE operation, if any,
it is used in.
In future this method could be extended to aggregate other information
that is hard to aggregate during parsing.
sql/sql_lex.h:
Add declaration for set_trg_event_type_for_tables().
sql/sql_parse.cc:
Call set_trg_event_type_for_tables() after MYSQLparse(). Remove tabs.
sql/sql_prepare.cc:
Call set_trg_event_type_for_tables() after MYSQLparse().
sql/sql_trigger.cc:
Call set_trg_event_type_for_tables() after MYSQLparse().
sql/sql_trigger.h:
Remove an obsolete member.
sql/sql_view.cc:
Call set_trg_event_type_for_tables() after MYSQLparse().
sql/sql_yacc.yy:
Move assignment of sp_head::m_type before calling sp_head::init_spname(),
one is now used inside another.
sql/table.cc:
Implement TABLE_LIST::set_trg_event_map() - a method that calculates
wh triggers may be fired on this table when executing a statement.
sql/table.h:
Add missing declarations.
Move declaration of trg_event_type from item.h (it will be needed for
trg_event_map bitmap when we start using Bitmap template instead
of uint8).
triggers".
Applying ALTER/OPTIMIZE/REPAIR TABLE statements to transactional table or to
table of any type on Windows caused disappearance of its triggers.
Bug was introduced in 5.0.19 by my fix for bug #13525 "Rename table does not
keep info of triggers" (see comment for sql_table.cc for more info).
.
mysql-test/r/trigger.result:
Added test-case covering handling of triggers when one does ALTER TABLE which
should move table to different database.
mysql-test/t/trigger.test:
Added test-case covering handling of triggers when one does ALTER TABLE which
should move table to different database.
sql/sql_table.cc:
mysql_alter_table():
Removal of strdup() which is no longer necessary allows us to preserve
nice assumption that "(new_db != db || new_table != table_name) indicates
that table will be renamed. So now we really can use this condition to
avoid updating trigger definitions when table is not renamed.
Note that we can't use (alter_info->flags & ALTER_RENAME) condition instead
since it can be also true when we do "ALTER TABLE t1 RENAME TO t1".
sql/sql_trigger.cc:
Table_triggers_list::change_table_name():
Mentioned assumption that subject table is not renamed to itself in method
description. Added DBUG_ASSERT() to catch wrong usage of this method.
mysql-test/r/trigger-trans.result:
New BitKeeper file ``mysql-test/r/trigger-trans.result''
mysql-test/t/trigger-trans.test:
New BitKeeper file ``mysql-test/t/trigger-trans.test''
