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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10.0(EOL), 10.1(EOL), 10.2(EOL), 10.3(EOL)
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10.3.6-1
Description
The test innodb.alter_crash fails due to a memory leak.
The reduced test case is as follows:
--source include/not_embedded.inc
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--source include/have_innodb.inc
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--source include/have_debug.inc
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CREATE TABLE t1(c1 INT) ENGINE=InnoDB; |
SET DEBUG_DBUG='+d,ib_create_table_fail_too_many_trx'; |
--error ER_TOO_MANY_CONCURRENT_TRXS
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CREATE INDEX c1 ON t1 (c1); |
--source include/restart_mysqld.inc
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DROP TABLE t1; |
The leak occurs when row_merge_create_index_graph() returns an error to row_merge_create_index(). The injected error is triggered when a SYS_INDEXES record is about to be inserted for the created index.
The error cannot be reproduced on MariaDB 10.0 or 10.1. A possible reason is that the code may have been refactored in WL#6501 TRUNCATE TABLE in MySQL 5.7.
Attachments
Issue Links
- relates to
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MDEV-13626 Merge InnoDB test cases from MySQL 5.7
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- Closed
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Activity
The memory leak is present also in MariaDB 10.0 and 10.1, possibly also 5.5. The test innodb.alter_crash was missing from 10.0 and 10.1. I ported it to 10.1 and plugged the memory leak in 10.1.39.
Memory leaks happens during addition of index in alter table.
Three operations happens in row_merge_create_index in 10.2 or create_dict_index (10.3)
(1) Insert the index entry in SYS_INDEXES system table.
(2) Insert the field entry in SYS_FIELDS system table.
(3) Create the b-tree for index and stores the root page number in SYS_INDEXES field.
Between (2) and (3), InnoDB adds the index into table cache. It checks whether
the index entry exceeds the half of the page. (dict_index_add_to_cache_w_vcol())
If any error happens during (1) and (2) then InnoDB doesn't free the heap memory
of an index. Luckily dict_index_add_to_cache_w_vcol() does free the heap memory
of an index irrespective of results.