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MDEV-16584 SP with a cursor inside a loop wastes THD memory aggressively

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Problem:

push_handler() created sp_handler_entry instances on THD::main_mem_root,
which is freed only after the SP instructions execution.
So in case of a CONTINUE HANDLER inside a loop (e.g. WHILE) this approach
leaked thread memory on every loop iteration.

Changes:
- Removing sp_handler_entry declaration, it's not really needed.
- Fixing the data type of sp_rcontext::m_handlers from
  Dynamic_array<sp_handler_entry*> to Dynamic_array<sp_instr_hpush_jump*>
- Fixing sp_rcontext::push_handler() to push the pointer to
  an sp_instr_hpush_jump instance to the handler stack.
  This instance contains everything we need.
  There is no a need to allocate anything else.
This commit is contained in:
Alexander Barkov
2018-06-28 16:55:42 +04:00
parent 445339feac
commit 724a5105cb
6 changed files with 107 additions and 48 deletions
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50
mysql-test/main/sp-condition-handler.test Normal file
View File

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--echo #
--echo # Start of 10.3 tests
--echo #
--echo #
--echo # MDEV-16595 SP with a CONTINUE HANDLER inside a loop wastes THD memory aggressively
--echo #
DELIMITER $$;
CREATE PROCEDURE p1()
BEGIN
DECLARE mem_used_old BIGINT UNSIGNED DEFAULT
(SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.SESSION_STATUS
WHERE VARIABLE_NAME='MEMORY_USED');
DECLARE i INT DEFAULT 1;
WHILE i <= 1000
DO
BEGIN
DECLARE msg TEXT;
DECLARE mem_used_cur BIGINT UNSIGNED DEFAULT
(SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.SESSION_STATUS
WHERE VARIABLE_NAME='MEMORY_USED');
DECLARE CONTINUE HANDLER FOR SQLSTATE '23000' SET @x=1;
DECLARE CONTINUE HANDLER FOR SQLSTATE '23001' SET @x=1;
DECLARE CONTINUE HANDLER FOR SQLSTATE '23002' SET @x=1;
DECLARE CONTINUE HANDLER FOR SQLSTATE '23003' SET @x=1;
DECLARE CONTINUE HANDLER FOR SQLSTATE '23004' SET @x=1;
DECLARE CONTINUE HANDLER FOR SQLSTATE '23005' SET @x=1;
DECLARE CONTINUE HANDLER FOR SQLSTATE '23006' SET @x=1;
DECLARE CONTINUE HANDLER FOR SQLSTATE '23007' SET @x=1;
DECLARE CONTINUE HANDLER FOR SQLSTATE '23008' SET @x=1;
IF (mem_used_cur >= mem_used_old * 1.1) THEN
SHOW STATUS LIKE 'Memory_used';
SET msg=CONCAT('Memory leak detected: i=', i, ' mem_used_old=',mem_used_old,' mem_used_cur=', mem_used_cur);
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT=msg;
END IF;
END;
SET i=i+1;
END WHILE;
END;
$$
DELIMITER ;$$
CALL p1;
DROP PROCEDURE p1;
--echo #
--echo # End of 10.3 tests
--echo #