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MDEV-31578 DECLARE CURSOR: "Memory not freed: 280 bytes lost" on syntax error

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When CURSOR parameters get parsed, their sp_assignment_lex instances
(one instance per parameter) get collected to List<sp_assignment_lex>.

These instances get linked to sphead only in the end of the list.
If a syntax error happened in the middle of the parameter list,
these instances were not deleted, which caused memory leaks.

Fix:

using a Bison %destructor to free rules of the <sp_assignment_lex_list>
type (on syntax errors).

Afte the fix these sp_assignment_lex instances from CURSOR parameters
deleted as follows:

- If the CURSOR statement was fully parsed, then these instances
  get properly linked to sp_head structures, so they are deleted
  during ~sp_head (this did not change)

- If the CURSOR statement failed on a syntax error, then by Bison's
  %destructor (this is being added in the current patch).
This commit is contained in:
Alexander Barkov
2023-06-29 17:30:02 +04:00
parent 0d3720c12a
commit fdab2c4c64
4 changed files with 66 additions and 1 deletions
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25
mysql-test/main/sp-memory-leak.test
View File

@ -27,3 +27,28 @@ BEGIN NOT ATOMIC
END
$$
DELIMITER ;$$
--echo #
--echo # MDEV-31578 DECLARE CURSOR: "Memory not freed: 280 bytes lost" on syntax error
--echo #
DELIMITER $$;
--error ER_PARSE_ERROR
BEGIN NOT ATOMIC
DECLARE cur CURSOR (a INT) FOR SELECT a+1;
OPEN cur(sp_followed_by_syntax_error();
CLOSE cur;
END;
$$
DELIMITER ;$$
DELIMITER $$;
--error ER_PARSE_ERROR
BEGIN NOT ATOMIC
DECLARE cur CURSOR (a INT) FOR SELECT a+1;
OPEN cur(1,sp_followed_by_syntax_error();
CLOSE cur;
END;
$$
DELIMITER ;$$