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.
identical to another in result"
According to SQL standard queries like
"select t1.a as col from t1, t2 order by a" should return an error if
both tables contain field a.
Added a test case for bug #5333.
null_key.result, key_primary.result:
Made covering index usable for const tables.
sql_select.cc:
Made covering index usable for const tables:
downported the corresponding code from 4.1.
Simultaneously fixed bug #5333 reported for 4.1.
The bug was due to the fact that field index in join
structures was always set to 0 for const tables.
Use 'mysqltest' as test database instead of test_$1 or test1,test2 to not accidently delete an important database
Safety fix for mailformed MERGE files
execute crashes server": we were deleting lex->result
after each execute, but prepared statements assumed that
it's left intact.
The fix adds cleanup() method to select_result hierarchy,
so that result objects can be reused.
Plus we now need to delete result objects more wisely.
* When executing EXPLAIN, do the same as for the query: convert join type to JT_CONST if keyuse array covers all key parts and all of them are constants.
* In remove_const, don't remove conditions that depend on some-const-table and current-table.
a second time". The bug was caused by incompatibility of
negations elimination algorithm and PS: during first statement
execute a subtree with negation was replaced with equivalent
subtree without NOTs.
The problem was that although this transformation was permanent,
items of the new subtree were created in execute-local memory.
The patch adds means to check if it is the first execute of a
prepared statement, and if this is the case, to allocate items
in memory of the prepared statement.
The implementation:
- backports Item_arena from 5.0
- adds Item_arena::is_stmt_prepare(),
Item_arena::is_first_stmt_execute().
- deletes THD::allocate_temporary_pool_for_ps_preparing(),
THD::free_temporary_pool_for_ps_preparing(); they
were redundant.
and adds a few invariants:
- thd->free_list never contains junk (= freed items)
- thd->current_arena is never null. If there is no
prepared statement, it points at the thd.
The rest of the patch contains mainly mechanical changes and
cleanups.
When in find_item_in_list() we are looking for item we should take into account unaliased
names of the fields but only if item with such aliased name is not found.
Also we should ignore aliases when looking for fully specified field.
from the select list and TEXT field
make setup_copy_fields to insert Item_copy_string for blobs in
the beginning of the copy_funcs (push_back instead of push_front)
the thing is that Item_copy_string::copy for function can call
Item_copy_string::val_int for blob via Item_ref.
But if Item_copy_string::copy for blob isn't called before,
it's value will be wrong.
So all the Item_copy_string::copy for blobs should be called before
Item_copy_string::copy for functions.
Added test case for bug #4767.
item_sum.cc:
Added a correct setting of the maybe_null flag for a copy of
an Item_sum object where the argument was a field of an inner table
in an outer join read from a temporary table.
It's part of the fix for bug #4767.
sql_select.cc:
Made change_refs_to_tmp_fields work correctly
for test case of bug #4767 where Item_sum::get_tmp_table_item
failed to build a correct copy of an Item_sum object referring
to a field in a temporary table.
It looks like a hack yet.
Instead of trying to open time zone tables during calculation of CONVERT_TZ() function
or setting of @@time_zone variable we should open and lock them with the rest of
statement's table (so we should add them to global table list) and after that use such
pre-opened tables for loading info about time zones.
new tests to ensure that prepared statement *really* work
(and that MySQL not picks up some number from arbitrary location
that happens to match the parameter's value)
