Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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5.5.38
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Debian/jessie - ONLY tested with MySQL (5.5.37, 5.5.38, 5.5.40, 5.6.21, 5.7.4)
Description
Hey MariaDB Team,
I've submitted the following bug to MySQL, as I have no MariaDB environment to test it myself, I'm only able to copy / paste here.
They have hidden their bug report.
Please mark as hidden as well if it makes sense for you!
This is a rather complicated problem with crashing the MySQL server, so that mysql_safe has to restart it.
I'm not sure how to classify the problem, so I try to describe it.
Choosing severity S2, because the whole mysqld crashes from a user proc.
Please note: the crash does happen with INNODB being used as engine for a temporary table.
Context:
A function is called
- the function calls a procedure to generate some cache
- the procedure creates a temporary table (if not exists)
- table is getting cleaned of outdated rows
- table is checked for cache data (for the arguments supplied)
- cache is generated
- the generated cache is queried and summarized to some extend
- function returns a value
The crash:
140728 14:24:12 InnoDB: Assertion failure in thread 139778932287232 in file row0mysql.c line 1463
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InnoDB: Failing assertion: node->pcur->rel_pos == BTR_PCUR_ON
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InnoDB: We intentionally generate a memory trap.
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---snip---
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Full stacktrace can be supplied when needed.
The proc and function is derived from a SLA calculation tool.
The crash does NOT happen when:
- ENGINE=MEMORY is used
- the table is not created as a temporary one
Regards
Markus
--
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-- the procedure
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--
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DROP PROCEDURE IF EXISTS cachedata;
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DELIMITER $$
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CREATE PROCEDURE cachedata(
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IN obj_id BIGINT UNSIGNED,
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IN start DATETIME,
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IN end DATETIME
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)
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cachedata:BEGIN
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DECLARE cache_count BIGINT;
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SET @timestamp := NOW();
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CREATE TEMPORARY TABLE IF NOT EXISTS cachedata (
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timestamp DATETIME,
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object_id BIGINT UNSIGNED NOT NULL,
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start DATETIME,
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end DATETIME,
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seqno BIGINT AUTO_INCREMENT,
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value FLOAT,
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PRIMARY KEY (seqno),
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INDEX (timestamp),
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INDEX (object_id, start, end)
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) ENGINE=INNODB;
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DELETE FROM cachedata WHERE
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timestamp < DATE_SUB(@timestamp, INTERVAL 15 SECOND);
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SELECT count(*) INTO cache_count FROM cachedata WHERE
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object_id = obj_id
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AND start = start
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AND end = end;
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IF cache_count > 0 THEN LEAVE cachedata;
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END IF;
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-- some fake cache
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INSERT INTO cachedata (timestamp, object_id, start, end, value) VALUES
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(@timestamp, obj_id, start, end, 1234),
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(@timestamp, obj_id, start, end, 4567),
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(@timestamp, obj_id, start, end, 8901),
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(@timestamp, obj_id, start, end, 1234),
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(@timestamp, obj_id, start, end, 4567),
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(@timestamp, obj_id, start, end, 8901),
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(@timestamp, obj_id, start, end, 1234),
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(@timestamp, obj_id, start, end, 4567),
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(@timestamp, obj_id, start, end, 8901),
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(@timestamp, obj_id, start, end, 1234),
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(@timestamp, obj_id, start, end, 4567),
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(@timestamp, obj_id, start, end, 8901),
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(@timestamp, obj_id, start, end, 2345),
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(@timestamp, obj_id, start, end, 1234),
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(@timestamp, obj_id, start, end, 4567),
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(@timestamp, obj_id, start, end, 8901),
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(@timestamp, obj_id, start, end, 2345),
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(@timestamp, obj_id, start, end, 1234),
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(@timestamp, obj_id, start, end, 4567),
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(@timestamp, obj_id, start, end, 8901),
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(@timestamp, obj_id, start, end, 2345);
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END$$
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--
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-- the function
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--
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DROP FUNCTION IF EXISTS get_cache$$
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CREATE FUNCTION get_cache(
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obj_id BIGINT UNSIGNED,
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start DATETIME,
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end DATETIME
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)
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RETURNS FLOAT
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READS SQL DATA
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BEGIN
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DECLARE result FLOAT;
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CALL cachedata(obj_id, start, end);
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-- calculate something
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SELECT SUM(value) INTO result FROM cachedata WHERE
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object_id = obj_id
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AND start = start
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AND end = end;
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RETURN result;
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END$$
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DELIMITER ;
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--
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-- INSTRUCTIONS
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--
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-- import the FUNC and PROC above
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-- run a query:
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SELECT get_cache(1, '2014-01-01', '2014-02-01');
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-- now wait a bit, from 15-60 seconds in my tests
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-- then rerun the query
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-- MySQL crashes
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Attachments
Issue Links
- is part of
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MDEV-7564 5.5.42 merge
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- Closed
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- links to