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  1. MariaDB Server
  2. MDEV-628

LP:989055 - Querying myisam table metadata may corrupt the table

        Details

        • Type: Bug
        • Status: Closed
        • Priority: Major
        • Resolution: Fixed
        • Affects Version/s: None
        • Fix Version/s: 5.5.30
        • Component/s: None
        • Labels:

          Description

          This is related to bug lp:925377, but confirmed on the 5.3.6 release.

          Jervin R (viiin) wrote a reproducer which I have attached (myisam_crash.rb) and confirm causes the corrupt table message. We're seeing corrupt tables on our live databases as well.

          This bug appears to be present still on 5.3.6 - possibly not during ENABLE|DISABLE keys but immediately before drop. see my.cnf below and Ruby script for test case.

          [mysqld]
basedir=/home/revin/Downloads/mariadb-5.3.6-Linux-x86_64/
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=revin
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

collation_server = utf8_unicode_ci
character_set_server = utf8
skip-external-locking
#fast_index_creation = false

# 10MB ramdisk - can be ignored
tmpdir = /tmpfs

key_buffer = 276M
innodb_buffer_pool_size = 276M
max_allowed_packet = 16M
thread_stack = 256K
thread_cache_size = 128
thread_concurrency = 8
max_connections = 512
table_cache = 2048
myisam-recover = BACKUP
query_cache_limit = 1M
query_cache_size = 128M
expire_logs_days = 10
max_binlog_size = 100M

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

          Produces the output:
          120426 11:32:39 [ERROR] mysqld: Table './test/customerXX' is marked as crashed and should be repaired

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                7 older comments
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                ratzpo Rasmus Johansson added a comment -

                Launchpad bug id: 989055

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                ratzpo Rasmus Johansson added a comment - Launchpad bug id: 989055
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                monty Michael Widenius added a comment -

                The problem was that ALTER TABLE ENABLE KEYS was not protecting against SHOW COMMANDS that opening the table.
                The same goes for REPAIR and OPTIMIZE TABLE.
                All of the above commands assumes (at least for MyISAM and Aria) that no one will access the storage engine handler until the repair has been done.

                I am now testing a fix that should solve this issue by having SHOW commands wait for an alter table or repair to finish.

                Show
                monty Michael Widenius added a comment - The problem was that ALTER TABLE ENABLE KEYS was not protecting against SHOW COMMANDS that opening the table. The same goes for REPAIR and OPTIMIZE TABLE. All of the above commands assumes (at least for MyISAM and Aria) that no one will access the storage engine handler until the repair has been done. I am now testing a fix that should solve this issue by having SHOW commands wait for an alter table or repair to finish.
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                monty Michael Widenius added a comment -

                Fixed and pushed into 5.5 tree

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                monty Michael Widenius added a comment - Fixed and pushed into 5.5 tree
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                elenst Elena Stepanova added a comment -

                Reopening for a moment to modify the 'Fix version' field

                Show
                elenst Elena Stepanova added a comment - Reopening for a moment to modify the 'Fix version' field
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                elenst Elena Stepanova added a comment -

                Since the fix was only pushed into 5.5, I removed 5.1/5.2/5.3 from 'Fix version'

                Show
                elenst Elena Stepanova added a comment - Since the fix was only pushed into 5.5, I removed 5.1/5.2/5.3 from 'Fix version'

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                  • Assignee:
                    Unassigned
                    Reporter:
                    jasonparrott Jason Parrott
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                    • Created:
                      Updated:
                      Resolved: