Bug#19022 "Memory bug when switching db during trigger execution"
Bug#17199 "Problem when view calls function from another database."
Bug#18444 "Fully qualified stored function names don't work correctly in
SELECT statements"
Documentation note: this patch introduces a change in behaviour of prepared
statements.
This patch adds a few new invariants with regard to how THD::db should
be used. These invariants should be preserved in future:
- one should never refer to THD::db by pointer and always make a deep copy
(strmake, strdup)
- one should never compare two databases by pointer, but use strncmp or
my_strncasecmp
- TABLE_LIST object table->db should be always initialized in the parser or
by creator of the object.
For prepared statements it means that if the current database is changed
after a statement is prepared, the database that was current at prepare
remains active. This also means that you can not prepare a statement that
implicitly refers to the current database if the latter is not set.
This is not documented, and therefore needs documentation. This is NOT a
change in behavior for almost all SQL statements except:
- ALTER TABLE t1 RENAME t2
- OPTIMIZE TABLE t1
- ANALYZE TABLE t1
- TRUNCATE TABLE t1 --
until this patch t1 or t2 could be evaluated at the first execution of
prepared statement.
CURRENT_DATABASE() still works OK and is evaluated at every execution
of prepared statement.
Note, that in stored routines this is not an issue as the default
database is the database of the stored procedure and "use" statement
is prohibited in stored routines.
This patch makes obsolete the use of check_db_used (it was never used in the
old code too) and all other places that check for table->db and assign it
from THD::db if it's NULL, except the parser.
How this patch was created: THD::{db,db_length} were replaced with a
LEX_STRING, THD::db. All the places that refer to THD::{db,db_length} were
manually checked and:
- if the place uses thd->db by pointer, it was fixed to make a deep copy
- if a place compared two db pointers, it was fixed to compare them by value
(via strcmp/my_strcasecmp, whatever was approproate)
Then this intermediate patch was used to write a smaller patch that does the
same thing but without a rename.
TODO in 5.1:
- remove check_db_used
- deploy THD::set_db in mysql_change_db
See also comments to individual files.
Stored procedure execution sometimes placed the address of auto variables
in the list of Item changes to undo in THD::rollback_item_tree_changes().
This could cause stack corruption.
Removed sp-goto.test, sp-goto.result and all (disabled) GOTO code.
Also removed some related code that's not needed any more (no possible
unresolved label references any more, so no need to check for them).
NB: Keeping the ER_SP_GOTO_IN_HNDLR in errmsg.txt; it might become useful
in the future, and removing it (and thus re-enumerating error codes)
might upset things. (Anything referring to explicit error codes.)
Also added comments, and fixing some coding style (mostly in comments too).
There are no functional changes, so no tests or documentation needed.
(This was originally part of a bugfix, but it was decided to not include this
in that patch; instead it's done separately.)
The idea is to add DEFINER-clause in CREATE PROCEDURE and CREATE FUNCTION
statements. Almost all support of definer in stored routines had been already
done before this patch.
NOTE: this patch changes behaviour of dumping stored routines in mysqldump.
Before this patch, mysqldump did not dump DEFINER-clause for stored routines
and this was documented behaviour. In order to get full information about stored
routines, one should have dumped mysql.proc table. This patch changes this
behaviour, so that DEFINER-clause is dumped.
Since DEFINER-clause is not supported in CREATE PROCEDURE | FUNCTION statements
before this patch, the clause is covered by additional version-specific comments.
After trying multiple inheritance (to messy and hard make it work) and
sublassing jump_if_not (worked, but ugly), decided to on this solution
instead:
Inserting an abstract sp_instr_opt_meta class as parent for all instructions
with destinations makes it possible to handle a continuation pointer for
sp_instr_set_case_expr too.
Note: No special test case; the fix is captured by the changed behaviour of
bug14643_2, and bug14498_4 (formerly disabled), in sp.test.
Second version.
The problem was that the optimizer didn't work correctly with forwards jumps
to "no-op" hpop and cpop instructions.
Don't generate "no-op" instructions (hpop 0 and cpop 0), it isn't actually
necessary.
- Fixed tests
- Optimized new code
- Fixed some unlikely core dumps
- Better bug fixes for:
- #14397 - OPTIMIZE TABLE with an open HANDLER causes a crash
- #14850 (ERROR 1062 when a quering a view using a Group By on a column that can be null
according to the standard.
The idea is to use Field-classes to implement stored routines
variables. Also, we should provide facade to Item-hierarchy
by Item_field class (it is necessary, since SRVs take part
in expressions).
The patch fixes the following bugs:
- BUG#8702: Stored Procedures: No Error/Warning shown for inappropriate data
type matching;
- BUG#8768: Functions: For any unsigned data type, -ve values can be passed
and returned;
- BUG#8769: Functions: For Int datatypes, out of range values can be passed
and returned;
- BUG#9078: STORED PROCDURE: Decimal digits are not displayed when we use
DECIMAL datatype;
- BUG#9572: Stored procedures: variable type declarations ignored;
- BUG#12903: upper function does not work inside a function;
- BUG#13705: parameters to stored procedures are not verified;
- BUG#13808: ENUM type stored procedure parameter accepts non-enumerated
data;
- BUG#13909: Varchar Stored Procedure Parameter always BINARY string (ignores
CHARACTER SET);
- BUG#14161: Stored procedure cannot retrieve bigint unsigned;
- BUG#14188: BINARY variables have no 0x00 padding;
- BUG#15148: Stored procedure variables accept non-scalar values;
impossible view security".
We should not expose names of tables which are explicitly or implicitly (via
routine or trigger) used by view even if we find that they are missing.
So during building of list of prelocked tables for statement we track which
routines (and therefore tables for these routines) are used from views. We
mark elements of LEX::routines set which correspond to routines used in views
by setting Sroutine_hash_entry::belong_to_view member to point to TABLE_LIST
object for topmost view which uses routine. We propagate this mark to all
routines which are used by this routine and which we add to this set. We also
mark tables used by such routine which we add to the list of tables for
prelocking as belonging to this view.
Since long, the compiled code of stored routines has been printed in the trace file
when starting mysqld with the "--debug" flag. (At creation time only, and only in
debug builds of course.) This has been helpful when debugging stored procedure
execution, but it's a bit awkward to use. Also, the printing of some of the
instructions is a bit terse, in particular for sp_instr_stmt where only the command
code was printed.
This improves the printout of several of the instructions, and adds the debugging-
only commands "show procedure code <name>" and "show function code <name>".
(In non-debug builds they are not available.)
The crash mentioned in original bug report is already prevented by one
of previous patches (fix for bug #13343 "CREATE|etc TRIGGER|VIEW|USER
don't commit the transaction (inconsistency)"), this patch only improve
error returning.
The problem was to continue at the right place in the code after the
test expression in a flow control statement fails with an exception
(internally, the test in sp_instr_jump_if_not), and the exception is
caught by a continue handler. Execution must then be resumed after the
the entire flow control statement (END IF, END WHILE, etc).
cursor is interpreted latin1 character and Bug#9819 "Cursors: Mysql Server
Crash while fetching from table with 5 million records."
A fix for a possible memory leak when fetching into an SP cursor
in a long loop.
The patch uses a common implementation of cursors in the binary protocol and
in stored procedures and implements materialized cursors.
For implementation details, see comments in sql_cursor.cc
Second version after review. Allow 'set autocommit' in procedures, but not
functions or triggers. Can return error in run-time (when a function calls
a procedure).
* Allocate thd->user_var_events elements on appropriate mem_root
* If several SP statements are binlogged as a single statement, collect all user var
accesses they make (grep for StoredRoutinesBinlogging for details)
The idea of the patch is to separate statement processing logic,
such as parsing, validation of the parsed tree, execution and cleanup,
from global query processing logic, such as logging, resetting
priorities of a thread, resetting stored procedure cache, resetting
thread count of errors and warnings.
This makes PREPARE and EXECUTE behave similarly to the rest of SQL
statements and allows their use in stored procedures.
This patch contains a change in behaviour:
until recently for each SQL prepared statement command, 2 queries
were written to the general log, e.g.
[Query] prepare stmt from @stmt_text;
[Prepare] select * from t1 <-- contents of @stmt_text
The chagne was necessary to prevent [Prepare] commands from being written
to the general log when executing a stored procedure with Dynamic SQL.
We should consider whether the old behavior is preferrable and probably
restore it.
This patch refixes Bug#7115, Bug#10975 (partially), Bug#10605 (various bugs
in Dynamic SQL reported before it was disabled).
"Interleaved SPs execution is now binlogged properly, "SELECT spfunc()" is binlogged too.
The known remaining issue is binlogging/replication of "a routine is deleted while it is executed" scenario.
NOT FOUND ...' in conditional handled incorrectly".
Whenever we remove an instruction during optimization, we need to
adjust instruction numbers (ip - instruction pointer) stored in all
instructions. In addition to that, sp_instr_hpush_jump, which
corresponds to DECLARE CONTINUE HANDLER needs adjustment for m_handler,
which holds the number of instruction with the continue handler.
In the bug report, a wrong ip stored in m_handler was pointing at
FETCH, which resulted in an error message and abnormal SP termination.
The fix is to just remove m_handler member from sp_instr_hpush_jump,
as it's always points to the instruction next to the DECLARE
statement itself (m_ip+1).
its body, but lets each statement to get/release its own locks. This allows a broader set
of statements to be executed inside PROCEDUREs (but breaks replication)
This patch should fix BUG#8072, BUG#8766, BUG#9563, BUG#11126
crash if referencing a table" and several other related bugs.
Fix for bug #11834 "Re-execution of prepared statement with dropped function
crashes server." which was spotted during work on previous bugs.
Also couple of nice cleanups:
- Replaced two separate hashes for stored routines used by statement with one.
- Now instead of doing one pass through all routines used in statement for
caching them and then doing another pass for adding their tables to table
list, we do only one pass during which do both things.
"Stored procedures: crash with function calling itself".
Disallow recursive stored routines until we either make Item's and LEX
reentrant safe or will use spearate sp_head instances (and thus separate
LEX objects and Item trees) for each routine invocation.
We need every instruction to have its own arena, because we want to
track instruction's state (INITIALIZED_FOR_SP -> EXECUTED). Because of
`if' statements and other conditional instructions used in stored
procedures, not every instruction of a stored procedure gets executed
during the first (or even subsequent) execution of the procedure.
So it's better if we track the execution state of every instruction
independently.
All instructions of a given procedure now also share sp_head's
mem_root, but keep their own free_list.
This simplifies juggling with free Item lists in sp_head::execute.
- free_items() moved to be a member of Query_arena.
- logic of 'backup_arena' debug member of Query_arena has been
changed to support
multi-backups. Until now, TRUE 'backup_arena' meant that there is
exactly one active backup of the THD arena. Now it means simply that
the arena is used for backup, so that we can't accidentally overwrite an
existing backup. This allows doing multiple backups, e.g. in
sp_head::execute and Cursor::fetch, when THD arena is already backed up
but we want to set yet another arena (usually the 'permanent' arena,
to save permanent transformations/optimizations of a parsed tree).
We can't have Item_trigger_field as aggregated object inside of
sp_instr_set_trigger_field class since in this case its destructor
will be called twice. So instead let us create this Item separately
and store pointer to it in instruction object.
