Analysis:
-------------------------------
According to the Manual
(http://dev.mysql.com/doc/refman/5.1/en/identifier-case-sensitivity.html):
"Column, index, stored routine, and event names are not case sensitive on any
platform, nor are column aliases."
In other words, 'lower_case_table_names' does not affect the behaviour of
those identifiers.
On the other hand, trigger names are case sensitive on some platforms,
and case insensitive on others. 'lower_case_table_names' does not affect
the behaviour of trigger names either.
The bug was that SHOW statements did case sensitive comparison
for stored procedure / stored function / event names.
Fix:
Modified the code so that comparison in case insensitive for routines
and events for "SHOW" operation.
As part of this commit, only fixing the test failures due to the actual code fix.
Analysis:
-------------------------------
According to the Manual
(http://dev.mysql.com/doc/refman/5.1/en/identifier-case-sensitivity.html):
"Column, index, stored routine, and event names are not case sensitive on any
platform, nor are column aliases."
In other words, 'lower_case_table_names' does not affect the behaviour of
those identifiers.
On the other hand, trigger names are case sensitive on some platforms,
and case insensitive on others. 'lower_case_table_names' does not affect
the behaviour of trigger names either.
The bug was that SHOW statements did case sensitive comparison
for stored procedure / stored function / event names.
Fix:
Modified the code so that comparison in case insensitive for routines
and events for "SHOW" operation.
KEY HANDLING ON SUBSEQUENT CREATE TABLE IF NOT EXISTS
PROBLEM:
--------
Consider a SP routine which does CREATE TABLE
with REFERENCES clause. The first call to this routine
invokes parser and the parsed items are cached, so as
to avoid parsing for the second execution of the routine.
It is obsevered that valgrind reports a warning
upon read of thd->lex->alter_info->key_list->Foreign_key object,
which seem to be pointing to a invalid memory address
during second time execution of the routine. Accessing this object
theoretically could cause a crash.
ANALYSIS:
---------
The problem stems from the fact that for some reason
elements of ref_columns list in thd->lex->alter_info->
key_list->Foreign_key object are changed to point to
objects allocated on runtime memory root.
During the first execution of routine we create
a copy of thd->lex->alter_info object.
As part of this process we create a clones of objects in
Alter_info::key_list and of Foreign_key object in particular.
Then Foreign_key object is cloned for some reason we
perform shallow copies of both Foreign_key::ref_columns
and Foreign_key::columns list. So new instance of
Foreign_key object starts to SHARE contents of ref_columns
and columns list with the original instance.
After that as part of cloning process we call
list_copy_and_replace_each_value() for elements of
ref_columns list. As result ref_columns lists in both
original and cloned Foreign_key object start to contain
pointers to Key_part_spec objects allocated on runtime
memory root because of shallow copy.
So when we start copying of thd->lex->alter_info object
during the second execution of stored routine we indeed
encounter pointer to the Key_part_spec object allocated
on runtime mem-root which was cleared during at the end
of previous execution. This is done in sp_head::execute(),
by a call to free_root(&execute_mem_root,MYF(0));
As result we get valgrind warnings about accessing
unreferenced memory.
FIX:
----
The safest solution to this problem is to
fix Foreign_key(Foreign_key, MEM_ROOT) constructor to do
a deep copy of columns lists, similar to Key(Key, MEM_ROOT)
constructor.
in different default schema.
In strict mode, when data truncation or conversion happens,
THD::killed is set to THD::KILL_BAD_DATA.
This is abuse of KILL mechanism to guarantee that execution
of statement is aborted.
The stored procedures execution, on the other hand,
upon detection that a connection was killed, would
terminate immediately, without trying to restore the caller's
context, in particular, restore the caller's current schema.
The fix is, when terminating a stored procedure execution,
to only bypass cleanup if the entire connection was killed,
not in case of other forms of KILL.
******
This patch fixes the following bugs:
- Bug#5889: Exit handler for a warning doesn't hide the warning in
trigger
- Bug#9857: Stored procedures: handler for sqlwarning ignored
- Bug#23032: Handlers declared in a SP do not handle warnings generated
in sub-SP
- Bug#36185: Incorrect precedence for warning and exception handlers
The problem was in the way warnings/errors during stored routine execution
were handled. Prior to this patch the logic was as follows:
- when a warning/an error happens: if we're executing a stored routine,
and there is a handler for that warning/error, remember the handler,
ignore the warning/error and continue execution.
- after a stored routine instruction is executed: check for a remembered
handler and activate one (if any).
This logic caused several problems:
- if one instruction generates several warnings (errors) it's impossible
to choose the right handler -- a handler for the first generated
condition was chosen and remembered for activation.
- mess with handling conditions in scopes different from the current one.
- not putting generated warnings/errors into Warning Info (Diagnostic
Area) is against The Standard.
The patch changes the logic as follows:
- Diagnostic Area is cleared on the beginning of each statement that
either is able to generate warnings, or is able to work with tables.
- at the end of a stored routine instruction, Diagnostic Area is left
intact.
- Diagnostic Area is checked after each stored routine instruction. If
an instruction generates several condition, it's now possible to take a
look at all of them and determine an appropriate handler.
This bug is just one facet of stored routines not being able to
detect changes in meta-data (WL#4179). This particular problem
can be triggered within a single session due to the improper
management of the pre-locking list if the view is expanded after
the pre-locking list is calculated.
Since the overall solution for the meta-data detection issue is
planned for a later release, for now a workaround is used to
fix this particular aspect that only involves a single session.
The workaround is to flush the thread-local stored routine cache
every time a view is created or modified, causing locally cached
routines to be re-evaluated upon invocation.
The problem was that a DROP TRIGGER statement inside a stored
procedure could cause a crash in subsequent invocations. This
was due to the addition, on the first execution, of a temporary
table reference to the stored procedure query table list. In
a subsequent invocation, there would be a attempt to reinitialize
the temporary table reference, which by then was already gone.
The solution is to backup and reset the query table list each
time a trigger needs to be dropped. This ensures that any temp
changes to the query table list are discarded. It is safe to
do so at this time as drop trigger is restricted from more
complicated scenarios (ie, not allowed within stored functions,
etc).
SP variables
A function call may end without throwing an error or without setting
the return value. This can happen when e.g. an error occurs while
calculating the return value.
Fixed by setting the value to NULL when error occurs during evaluation
of an expression.
