crashes server." The fix makes Item_func_rand prepared-statements
aware plus it fixes the case when RAND is used in prepared
statements and replication is on (as well as several similar issues).
Until now we did not reset THD before every execution of a prepared
statement, so if some execution had set thd->time_zone_used
or thd->rand_used they would not be reset until next mysql_parse.
Some of post-review fixes done.
BUG#4335 - one name can be handler open'ed many times.
Fixed problems detected on Windows build by VC++.
Removed unused variables.
Applied a neccessary cast.
Change error code to HA_ERR_ROW_IS_REFERENCED if we cannot DROP a parent table referenced by a FOREIGN KEY constraint; this error number is less misleading than the previous value HA_ERR_CANNOT_ADD_FOREIGN, but misleading still; we should introduce to 5.0 a proper MySQL error code
A fix for Bug#6042 "constants propogation works olny once (prepared
statements)": reset item->marker in Item::cleanup, as it's used
in propogate_cond_constants. No test case as the only way I could
come up with to show the problem is EXPLAIN, and EXPLAIN is painful
to use in the test suite.
when one connection had done FLUSH TABLES WITH READ LOCK, some updates, and then COMMIT,
it was accepted but my_error() was called and so, while client got no error, error was logged in binlog.
We now don't call my_error() in this case; we assume the connection know what it does.
This problem was specific to 4.0.21. The change is needed to make replication work with existing versions of innobackup.
(Bug #4315: GROUP_CONCAT with ORDER BY returns strange results for TEXT fields
Bug #5564: Strange behaviour with group_concat and distinct
Bug #5970: group_concat doesn't print warnings)
crashes server (prepared statements)": the bug was that all boolean
items always recovered its original arguments at statement cleanup
stage.
This collided with Item_subselect::select_transformer, which tries to
permanently change the item tree to use a transformed subselect instead of
original one.
So we had this call sequence for prepare:
mysql_stmt_prepare -> JOIN::prepare ->
Item_subselect::fix_fields -> the item tree gets transformed ->
Item_bool_rowready_func2::cleanup, item tree is recovered to original
state, while it shouldn't have been;
mysql_stmt_execute -> attempts to execute a broken tree -> crash.
Now instead of bluntly recovering all arguments of bool functions in
Item_bool_rowready_func2::cleanup, we recover only those
which were changed, and do it in one place.
There still would exist a possibility for a collision with subselect
tranformation, if permanent and temporary changes were performed at the
same stage.
But fortunately subselect transformation is always done first, so it
doesn't conflict with the optimization done by propogate_cond_constants.
Now we have:
mysql_stmt_prepare -> JOIN::prepare -> subselect transformation
permanently changes the tree -> cleanup doesn't recover anything,
because nothing was registered for recovery.
mysql_stmt_execute -> JOIN::prepare (the tree is already transformed,
so it doesn't change), JOIN::optimize ->
propogate_cond_constants -> temporary changes the item tree
with constants -> JOIN::execute -> cleanup ->
the changes done by propogate_cond_constants are recovered, as
they were registered for recovery.
