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  1. MariaDB Server
  2. MDEV-8302

Duplicate key with parallel replication

    Details

      Description

      Hello,

      we are having a random "duplicate key" problem with parallel replication. We were trying hard to reproduce it on our test servers as well, but currently it only happens on our live servers.

      The error we get is the following:

      150604  2:56:41 [ERROR] Slave SQL: Error 'Duplicate entry 'VerifyOrder_0-249' for key 'identry_idqueue'' on query. Default database: 'optovision'. Query: 'insert into `queueentry`(`identry`,`idqueue`,`entrydate`,`removedate`,`info`,`prio`,`reserved`,`ObjectContext`,`OriginHost`,`ReservingHost`,`UnreserveDate`,`ReservationCounter`,`OptimisticLockField`)values('VerifyOrder_0',249,'2015-06-04 02:56:40.687','2015-06-04 03:11:40.671','',0,null,'semaphore','172.16.185.22',null,null,0,0)', Gtid 0-3-454870355, Internal MariaDB error code: 1062
      150604  2:56:41 [Warning] Slave: Duplicate entry 'VerifyOrder_0-249' for key 'identry_idqueue' Error_code: 1062
      150604  2:56:41 [ERROR] Error running query, slave SQL thread aborted. Fix the problem, and restart the slave SQL thread with "SLAVE START". We stopped at log 'mysql-bin.007762' position 645226271; GTID position '77-3-552,0-3-454870353,3-3-2,2-3-469046,17-3-180,1-3-7'
      150604  2:56:41 [Note] Error reading relay log event: slave SQL thread was killed

      It is always the same table that is involved in this issue, and in all cases we analyzed in deep, it was the same value for the unique key to be written.

      The replication is based on one master and one slave, no restrictions on the data to be transferred, and no direct write requests to the slave. Once a day the slave is stopped for a short moment to synchronize the file system and take a backup on LVM level. At the moment we see no connection between this backup and the error (the point of time it happens seems to be independent)

      The table that is involved is defined as follows:

      CREATE TABLE `queueentry` (
      	`OID` INT(11) NOT NULL AUTO_INCREMENT,
      	`identry` VARCHAR(100) NOT NULL,
      	`entrydate` DATETIME NULL DEFAULT NULL,
      	`removedate` DATETIME NULL DEFAULT NULL,
      	`info` VARCHAR(8096) NULL DEFAULT NULL,
      	`prio` INT(11) NULL DEFAULT NULL,
      	`reserved` DATETIME NULL DEFAULT NULL,
      	`idqueue` INT(11) NOT NULL,
      	`ObjectContext` VARCHAR(200) NULL DEFAULT NULL,
      	`OriginHost` VARCHAR(200) NULL DEFAULT NULL,
      	`ReservingHost` VARCHAR(200) NULL DEFAULT NULL,
      	`UnreserveDate` DATETIME NULL DEFAULT NULL,
      	`ReservationCounter` INT(10) UNSIGNED NOT NULL DEFAULT '0',
      	`OptimisticLockField` INT(11) NULL DEFAULT NULL,
      	PRIMARY KEY (`OID`),
      	UNIQUE INDEX `identry_idqueue` (`identry`, `idqueue`),
      	INDEX `idqueue` (`idqueue`),
      	INDEX `entrydate_prio_reserved_idqueue` (`idqueue`, `reserved`, `prio`, `entrydate`),
      	INDEX `removedate` (`removedate`),
      	INDEX `entrydate` (`entrydate`),
      	INDEX `UnreserveDate_ReservationCounter` (`ReservationCounter`, `UnreserveDate`)
      )
      COLLATE='utf8_general_ci'
      ENGINE=InnoDB
      AUTO_INCREMENT=8164332;

      We analyzed the binlog of the master in those cases and found the following:

      • Just before this insert statement there are two transactions bound together for parallel replication.
      • Both of these transactions work on the same table as the insert does.
      • The second of these transactions deletes the entry with the unique key, that will be written by the statement showing the duplicate key error.

      That is the following two statements are bound together:

      insert into `queueentry`(`identry`,`idqueue`,`entrydate`,`removedate`,`info`,`prio`,`reserved`,`ObjectContext`,`OriginHost`,`ReservingHost`,`UnreserveDate`,`ReservationCounter`,`OptimisticLockField`)values('SME_PrintLabel_0',249,'2015-06-04 02:56:40.671','2015-06-04 03:11:40.656','',0,null,'semaphore','172.16.185.21',null,null,0,0)
      delete from `queueentry` where ((`OID` = 6363790) and (`OptimisticLockField` = 0))

      And then this next transaction crashes:

      insert into `queueentry`(`identry`,`idqueue`,`entrydate`,`removedate`,`info`,`prio`,`reserved`,`ObjectContext`,`OriginHost`,`ReservingHost`,`UnreserveDate`,`ReservationCounter`,`OptimisticLockField`)values('VerifyOrder_0',249,'2015-06-04 02:56:40.687','2015-06-04 03:11:40.671','',0,null,'semaphore','172.16.185.22',null,null,0,0)

      Here is the (I hope) most important part of the binlog of the master:

      #150604  2:56:40 server id 3  end_log_pos 645225814     GTID 0-3-454870353 cid=5620557227
      /*!100001 SET @@session.gtid_seq_no=454870353*//*!*/;
      BEGIN
      /*!*/;
      # at 645225814
      #150604  2:56:40 server id 3  end_log_pos 645225842     Intvar
      SET INSERT_ID=6363805/*!*/;
      # at 645225842
      #150604  2:56:40 server id 3  end_log_pos 645226244     Query   thread_id=19732488      exec_time=0     error_code=0
      SET TIMESTAMP=1433379400/*!*/;
      insert into `queueentry`(`identry`,`idqueue`,`entrydate`,`removedate`,`info`,`prio`,`reserved`,`ObjectContext`,`OriginHost`,`ReservingHost`,`UnreserveDate`,`ReservationCounter`,`OptimisticLockField`)values('SME_PrintLabel_0',249,'2015-06-04 02:56:40.671','2015-06-04 03:11:40.656','',0,null,'semaphore','172.16.185.21',null,null,0,0)
      /*!*/;
      # at 645226244
      #150604  2:56:40 server id 3  end_log_pos 645226271     Xid = 5620557224
      COMMIT/*!*/;
      # at 645226271
      #150604  2:56:40 server id 3  end_log_pos 645226311     GTID 0-3-454870354 cid=5620557227
      /*!100001 SET @@session.gtid_seq_no=454870354*//*!*/;
      BEGIN
      /*!*/;
      # at 645226311
      #150604  2:56:40 server id 3  end_log_pos 645226462     Query   thread_id=19732489      exec_time=0     error_code=0
      SET TIMESTAMP=1433379400/*!*/;
      delete from `queueentry` where ((`OID` = 6363790) and (`OptimisticLockField` = 0))
      /*!*/;
      # at 645226462
      #150604  2:56:40 server id 3  end_log_pos 645226489     Xid = 5620557228
      COMMIT/*!*/;
      # at 645226489
      #150604  2:56:40 server id 3  end_log_pos 645226527     GTID 0-3-454870355
      /*!100001 SET @@session.gtid_seq_no=454870355*//*!*/;
      BEGIN
      /*!*/;
      # at 645226527
      #150604  2:56:40 server id 3  end_log_pos 645226555     Intvar
      SET INSERT_ID=6363806/*!*/;
      # at 645226555
      #150604  2:56:40 server id 3  end_log_pos 645226954     Query   thread_id=19732488      exec_time=0     error_code=0
      SET TIMESTAMP=1433379400/*!*/;
      insert into `queueentry`(`identry`,`idqueue`,`entrydate`,`removedate`,`info`,`prio`,`reserved`,`ObjectContext`,`OriginHost`,`ReservingHost`,`UnreserveDate`,`ReservationCounter`,`OptimisticLockField`)values('VerifyOrder_0',249,'2015-06-04 02:56:40.687','2015-06-04 03:11:40.671','',0,null,'semaphore','172.16.185.22',null,null,0,0)
      /*!*/;
      # at 645226954
      #150604  2:56:40 server id 3  end_log_pos 645226981     Xid = 5620557238
      COMMIT/*!*/;
      # at 645226981

      The following additional observations we made:

      • The replication error only happens when the slave is at least one second behind the master. So it seems to us that there is somewhere a race condition at work which only happens when the slave is working very fast on the transactions from the master.
      • When this error happens, the command "stop slave" does not work any longer. We have to kill the database process, since some slave transactions are still waiting on each other.
      • After a restart of the database server we examine the table, and we cannot see the malicious key in the table any longer (even before the restart it is not there). We can restart the replication without further actions.
      • When we restart the replication, the slave is normally a few minutes behind the master. While catching up, we normally get the same error again.
      • As far as we can see, it is always the value 'VerifyOrder_0' that is causing the error, even though other values are written to that table as often as that value. We find this interesting, since it is - in alphabetical order - the largest value that is being stored in that table at the moment. I have only a rough understanding about indexes in databases, but I wonder if this could be related to an index reorganization due to the previous insert and delete statements.
      • The error vanishes if we set binlog_commit_wait_count=0 on the master (which is our current workaround).

      The variables on our slave are set as follows:

      'Variable_name','Value'
      'aria_block_size','8192'
      'aria_checkpoint_interval','30'
      'aria_checkpoint_log_activity','1048576'
      'aria_force_start_after_recovery_failures','0'
      'aria_group_commit','none'
      'aria_group_commit_interval','0'
      'aria_log_file_size','1073741824'
      'aria_log_purge_type','immediate'
      'aria_max_sort_file_size','9223372036853727232'
      'aria_page_checksum','ON'
      'aria_pagecache_age_threshold','300'
      'aria_pagecache_buffer_size','134217728'
      'aria_pagecache_division_limit','100'
      'aria_pagecache_file_hash_size','512'
      'aria_recover','NORMAL'
      'aria_repair_threads','1'
      'aria_sort_buffer_size','268434432'
      'aria_stats_method','nulls_unequal'
      'aria_sync_log_dir','NEWFILE'
      'aria_used_for_temp_tables','ON'
      'auto_increment_increment','1'
      'auto_increment_offset','1'
      'autocommit','ON'
      'automatic_sp_privileges','ON'
      'back_log','150'
      'basedir','/usr'
      'big_tables','OFF'
      'binlog_annotate_row_events','OFF'
      'binlog_cache_size','32768'
      'binlog_checksum','NONE'
      'binlog_commit_wait_count','0'
      'binlog_commit_wait_usec','100000'
      'binlog_direct_non_transactional_updates','OFF'
      'binlog_format','MIXED'
      'binlog_optimize_thread_scheduling','ON'
      'binlog_stmt_cache_size','32768'
      'bulk_insert_buffer_size','8388608'
      'character_set_client','utf8'
      'character_set_connection','utf8'
      'character_set_database','utf8'
      'character_set_filesystem','binary'
      'character_set_results','utf8'
      'character_set_server','utf8'
      'character_set_system','utf8'
      'character_sets_dir','/usr/share/mysql/charsets/'
      'collation_connection','utf8_general_ci'
      'collation_database','utf8_general_ci'
      'collation_server','utf8_unicode_ci'
      'completion_type','NO_CHAIN'
      'concurrent_insert','AUTO'
      'connect_timeout','10'
      'datadir','/var/lib/mysql/'
      'date_format','%Y-%m-%d'
      'datetime_format','%Y-%m-%d %H:%i:%s'
      'deadlock_search_depth_long','15'
      'deadlock_search_depth_short','4'
      'deadlock_timeout_long','50000000'
      'deadlock_timeout_short','10000'
      'debug_no_thread_alarm','OFF'
      'default_master_connection',''
      'default_regex_flags',''
      'default_storage_engine','InnoDB'
      'default_week_format','0'
      'delay_key_write','ON'
      'delayed_insert_limit','100'
      'delayed_insert_timeout','300'
      'delayed_queue_size','1000'
      'div_precision_increment','4'
      'error_count','0'
      'event_scheduler','OFF'
      'expensive_subquery_limit','100'
      'expire_logs_days','5'
      'external_user',''
      'extra_max_connections','1'
      'extra_port','0'
      'flush','OFF'
      'flush_time','0'
      'foreign_key_checks','ON'
      'ft_boolean_syntax','+ -><()~*:""&|'
      'ft_max_word_len','84'
      'ft_min_word_len','4'
      'ft_query_expansion_limit','20'
      'ft_stopword_file','(built-in)'
      'general_log','OFF'
      'general_log_file','optosql5.log'
      'group_concat_max_len','1024'
      'gtid_binlog_pos','0-3-481964408,3-3-2,2-3-504931'
      'gtid_binlog_state','0-5-479038918,0-3-481964408,3-3-2,2-3-504931'
      'gtid_current_pos','77-3-552,0-3-481964408,3-3-2,2-3-504931,17-3-180,1-3-7'
      'gtid_domain_id','0'
      'gtid_ignore_duplicates','OFF'
      'gtid_seq_no','0'
      'gtid_slave_pos','77-3-552,0-3-481964408,3-3-2,2-3-504931,17-3-180,1-3-7'
      'gtid_strict_mode','OFF'
      'have_compress','YES'
      'have_crypt','YES'
      'have_dynamic_loading','YES'
      'have_geometry','YES'
      'have_openssl','YES'
      'have_profiling','YES'
      'have_query_cache','YES'
      'have_rtree_keys','YES'
      'have_ssl','DISABLED'
      'have_symlink','DISABLED'
      'histogram_size','0'
      'histogram_type','SINGLE_PREC_HB'
      'host_cache_size','128'
      'hostname','optosql5'
      'identity','0'
      'ignore_builtin_innodb','OFF'
      'ignore_db_dirs',''
      'in_transaction','0'
      'init_connect',''
      'init_file',''
      'init_slave',''
      'innodb_adaptive_flushing','ON'
      'innodb_adaptive_flushing_lwm','10.000000'
      'innodb_adaptive_hash_index','ON'
      'innodb_adaptive_hash_index_partitions','1'
      'innodb_adaptive_max_sleep_delay','150000'
      'innodb_additional_mem_pool_size','8388608'
      'innodb_api_bk_commit_interval','5'
      'innodb_api_disable_rowlock','OFF'
      'innodb_api_enable_binlog','OFF'
      'innodb_api_enable_mdl','OFF'
      'innodb_api_trx_level','0'
      'innodb_autoextend_increment','64'
      'innodb_autoinc_lock_mode','1'
      'innodb_buffer_pool_dump_at_shutdown','OFF'
      'innodb_buffer_pool_dump_now','OFF'
      'innodb_buffer_pool_filename','ib_buffer_pool'
      'innodb_buffer_pool_instances','8'
      'innodb_buffer_pool_load_abort','OFF'
      'innodb_buffer_pool_load_at_startup','OFF'
      'innodb_buffer_pool_load_now','OFF'
      'innodb_buffer_pool_populate','OFF'
      'innodb_buffer_pool_size','34359738368'
      'innodb_change_buffer_max_size','25'
      'innodb_change_buffering','all'
      'innodb_checksum_algorithm','innodb'
      'innodb_checksums','ON'
      'innodb_cleaner_lsn_age_factor','high_checkpoint'
      'innodb_cmp_per_index_enabled','OFF'
      'innodb_commit_concurrency','0'
      'innodb_compression_failure_threshold_pct','5'
      'innodb_compression_level','6'
      'innodb_compression_pad_pct_max','50'
      'innodb_concurrency_tickets','5000'
      'innodb_corrupt_table_action','assert'
      'innodb_data_file_path','ibdata1:12M:autoextend'
      'innodb_data_home_dir',''
      'innodb_disable_sort_file_cache','OFF'
      'innodb_doublewrite','ON'
      'innodb_empty_free_list_algorithm','backoff'
      'innodb_fake_changes','OFF'
      'innodb_fast_shutdown','1'
      'innodb_file_format','Antelope'
      'innodb_file_format_check','ON'
      'innodb_file_format_max','Antelope'
      'innodb_file_per_table','ON'
      'innodb_flush_log_at_timeout','1'
      'innodb_flush_log_at_trx_commit','1'
      'innodb_flush_method',''
      'innodb_flush_neighbors','1'
      'innodb_flushing_avg_loops','30'
      'innodb_force_load_corrupted','OFF'
      'innodb_force_recovery','0'
      'innodb_foreground_preflush','exponential_backoff'
      'innodb_ft_aux_table',''
      'innodb_ft_cache_size','8000000'
      'innodb_ft_enable_diag_print','OFF'
      'innodb_ft_enable_stopword','ON'
      'innodb_ft_max_token_size','84'
      'innodb_ft_min_token_size','3'
      'innodb_ft_num_word_optimize','2000'
      'innodb_ft_result_cache_limit','2000000000'
      'innodb_ft_server_stopword_table',''
      'innodb_ft_sort_pll_degree','2'
      'innodb_ft_total_cache_size','640000000'
      'innodb_ft_user_stopword_table',''
      'innodb_io_capacity','200'
      'innodb_io_capacity_max','2000'
      'innodb_kill_idle_transaction','0'
      'innodb_large_prefix','OFF'
      'innodb_lock_wait_timeout','50'
      'innodb_locking_fake_changes','ON'
      'innodb_locks_unsafe_for_binlog','OFF'
      'innodb_log_arch_dir','./'
      'innodb_log_arch_expire_sec','0'
      'innodb_log_archive','OFF'
      'innodb_log_block_size','512'
      'innodb_log_buffer_size','8388608'
      'innodb_log_checksum_algorithm','innodb'
      'innodb_log_compressed_pages','ON'
      'innodb_log_file_size','104857600'
      'innodb_log_files_in_group','2'
      'innodb_log_group_home_dir','./'
      'innodb_lru_scan_depth','1024'
      'innodb_max_bitmap_file_size','104857600'
      'innodb_max_changed_pages','1000000'
      'innodb_max_dirty_pages_pct','75.000000'
      'innodb_max_dirty_pages_pct_lwm','0.001000'
      'innodb_max_purge_lag','0'
      'innodb_max_purge_lag_delay','0'
      'innodb_mirrored_log_groups','1'
      'innodb_monitor_disable',''
      'innodb_monitor_enable',''
      'innodb_monitor_reset',''
      'innodb_monitor_reset_all',''
      'innodb_old_blocks_pct','37'
      'innodb_old_blocks_time','1000'
      'innodb_online_alter_log_max_size','134217728'
      'innodb_open_files','512'
      'innodb_optimize_fulltext_only','OFF'
      'innodb_page_size','16384'
      'innodb_print_all_deadlocks','OFF'
      'innodb_purge_batch_size','300'
      'innodb_purge_threads','1'
      'innodb_random_read_ahead','OFF'
      'innodb_read_ahead_threshold','56'
      'innodb_read_io_threads','64'
      'innodb_read_only','OFF'
      'innodb_replication_delay','0'
      'innodb_rollback_on_timeout','OFF'
      'innodb_rollback_segments','128'
      'innodb_sched_priority_cleaner','19'
      'innodb_show_locks_held','10'
      'innodb_show_verbose_locks','0'
      'innodb_simulate_comp_failures','0'
      'innodb_sort_buffer_size','1048576'
      'innodb_spin_wait_delay','6'
      'innodb_stats_auto_recalc','ON'
      'innodb_stats_method','nulls_equal'
      'innodb_stats_modified_counter','0'
      'innodb_stats_on_metadata','OFF'
      'innodb_stats_persistent','ON'
      'innodb_stats_persistent_sample_pages','20'
      'innodb_stats_sample_pages','8'
      'innodb_stats_traditional','ON'
      'innodb_stats_transient_sample_pages','8'
      'innodb_status_output','OFF'
      'innodb_status_output_locks','OFF'
      'innodb_strict_mode','OFF'
      'innodb_support_xa','ON'
      'innodb_sync_array_size','1'
      'innodb_sync_spin_loops','30'
      'innodb_table_locks','ON'
      'innodb_thread_concurrency','0'
      'innodb_thread_sleep_delay','10000'
      'innodb_track_changed_pages','OFF'
      'innodb_undo_directory','.'
      'innodb_undo_logs','128'
      'innodb_undo_tablespaces','0'
      'innodb_use_atomic_writes','OFF'
      'innodb_use_fallocate','OFF'
      'innodb_use_global_flush_log_at_trx_commit','ON'
      'innodb_use_native_aio','ON'
      'innodb_use_stacktrace','OFF'
      'innodb_use_sys_malloc','ON'
      'innodb_version','5.6.22-71.0'
      'innodb_write_io_threads','64'
      'insert_id','0'
      'interactive_timeout','28800'
      'join_buffer_size','131072'
      'join_buffer_space_limit','2097152'
      'join_cache_level','2'
      'keep_files_on_create','OFF'
      'key_buffer_size','134217728'
      'key_cache_age_threshold','300'
      'key_cache_block_size','1024'
      'key_cache_division_limit','100'
      'key_cache_file_hash_size','512'
      'key_cache_segments','0'
      'large_files_support','ON'
      'large_page_size','0'
      'large_pages','OFF'
      'last_gtid',''
      'last_insert_id','0'
      'lc_messages','en_US'
      'lc_messages_dir',''
      'lc_time_names','en_US'
      'license','GPL'
      'local_infile','ON'
      'lock_wait_timeout','31536000'
      'locked_in_memory','OFF'
      'log_bin','ON'
      'log_bin_trust_function_creators','OFF'
      'log_error','/var/log/mysqld.log'
      'log_output','FILE'
      'log_queries_not_using_indexes','OFF'
      'log_slave_updates','ON'
      'log_slow_filter','admin,filesort,filesort_on_disk,full_join,full_scan,query_cache,query_cache_miss,tmp_table,tmp_table_on_disk'
      'log_slow_rate_limit','1'
      'log_slow_verbosity',''
      'log_warnings','1'
      'long_query_time','10.000000'
      'low_priority_updates','OFF'
      'lower_case_file_system','OFF'
      'lower_case_table_names','1'
      'master_verify_checksum','OFF'
      'max_allowed_packet','33554432'
      'max_binlog_cache_size','18446744073709547520'
      'max_binlog_size','1073741824'
      'max_binlog_stmt_cache_size','18446744073709547520'
      'max_connect_errors','100'
      'max_connections','500'
      'max_delayed_threads','20'
      'max_error_count','64'
      'max_heap_table_size','67108864'
      'max_insert_delayed_threads','20'
      'max_join_size','18446744073709551615'
      'max_length_for_sort_data','1024'
      'max_long_data_size','33554432'
      'max_prepared_stmt_count','16382'
      'max_relay_log_size','1073741824'
      'max_seeks_for_key','4294967295'
      'max_sort_length','1024'
      'max_sp_recursion_depth','0'
      'max_tmp_tables','32'
      'max_user_connections','0'
      'max_write_lock_count','4294967295'
      'metadata_locks_cache_size','1024'
      'metadata_locks_hash_instances','8'
      'min_examined_row_limit','0'
      'mrr_buffer_size','262144'
      'multi_range_count','256'
      'myisam_block_size','1024'
      'myisam_data_pointer_size','6'
      'myisam_max_sort_file_size','9223372036853727232'
      'myisam_mmap_size','18446744073709551615'
      'myisam_recover_options','DEFAULT'
      'myisam_repair_threads','1'
      'myisam_sort_buffer_size','134216704'
      'myisam_stats_method','nulls_unequal'
      'myisam_use_mmap','OFF'
      'net_buffer_length','16384'
      'net_read_timeout','30'
      'net_retry_count','10'
      'net_write_timeout','60'
      'old','OFF'
      'old_alter_table','OFF'
      'old_mode',''
      'old_passwords','OFF'
      'open_files_limit','500005'
      'optimizer_prune_level','1'
      'optimizer_search_depth','62'
      'optimizer_selectivity_sampling_limit','100'
      'optimizer_switch','index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on,extended_keys=on,exists_to_in=on'
      'optimizer_use_condition_selectivity','1'
      'performance_schema','ON'
      'performance_schema_accounts_size','100'
      'performance_schema_digests_size','10000'
      'performance_schema_events_stages_history_long_size','10000'
      'performance_schema_events_stages_history_size','10'
      'performance_schema_events_statements_history_long_size','10000'
      'performance_schema_events_statements_history_size','10'
      'performance_schema_events_waits_history_long_size','10000'
      'performance_schema_events_waits_history_size','10'
      'performance_schema_hosts_size','100'
      'performance_schema_max_cond_classes','80'
      'performance_schema_max_cond_instances','400900'
      'performance_schema_max_file_classes','50'
      'performance_schema_max_file_handles','32768'
      'performance_schema_max_file_instances','2154'
      'performance_schema_max_mutex_classes','200'
      'performance_schema_max_mutex_instances','605000'
      'performance_schema_max_rwlock_classes','40'
      'performance_schema_max_rwlock_instances','202800'
      'performance_schema_max_socket_classes','10'
      'performance_schema_max_socket_instances','200020'
      'performance_schema_max_stage_classes','150'
      'performance_schema_max_statement_classes','180'
      'performance_schema_max_table_handles','800'
      'performance_schema_max_table_instances','12500'
      'performance_schema_max_thread_classes','50'
      'performance_schema_max_thread_instances','200100'
      'performance_schema_session_connect_attrs_size','512'
      'performance_schema_setup_actors_size','100'
      'performance_schema_setup_objects_size','100'
      'performance_schema_users_size','100'
      'pid_file','/var/lib/mysql/optosql5.pid'
      'plugin_dir','/usr/lib64/mysql/plugin/'
      'plugin_maturity','unknown'
      'port','3306'
      'preload_buffer_size','32768'
      'profiling','OFF'
      'profiling_history_size','15'
      'progress_report_time','5'
      'protocol_version','10'
      'proxy_user',''
      'pseudo_slave_mode','OFF'
      'pseudo_thread_id','189143'
      'query_alloc_block_size','8192'
      'query_cache_limit','1048576'
      'query_cache_min_res_unit','4096'
      'query_cache_size','67108864'
      'query_cache_strip_comments','OFF'
      'query_cache_type','ON'
      'query_cache_wlock_invalidate','OFF'
      'query_prealloc_size','8192'
      'rand_seed1','0'
      'rand_seed2','0'
      'range_alloc_block_size','4096'
      'read_buffer_size','131072'
      'read_only','ON'
      'read_rnd_buffer_size','262144'
      'relay_log',''
      'relay_log_index',''
      'relay_log_info_file','relay-log.info'
      'relay_log_purge','ON'
      'relay_log_recovery','OFF'
      'relay_log_space_limit','0'
      'replicate_annotate_row_events','OFF'
      'replicate_do_db',''
      'replicate_do_table',''
      'replicate_events_marked_for_skip','replicate'
      'replicate_ignore_db',''
      'replicate_ignore_table',''
      'replicate_wild_do_table',''
      'replicate_wild_ignore_table',''
      'report_host',''
      'report_password',''
      'report_port','3306'
      'report_user',''
      'rowid_merge_buff_size','8388608'
      'rpl_recovery_rank','0'
      'secure_auth','OFF'
      'secure_file_priv',''
      'server_id','5'
      'skip_external_locking','ON'
      'skip_name_resolve','ON'
      'skip_networking','OFF'
      'skip_replication','OFF'
      'skip_show_database','OFF'
      'slave_compressed_protocol','OFF'
      'slave_ddl_exec_mode','IDEMPOTENT'
      'slave_domain_parallel_threads','4'
      'slave_exec_mode','STRICT'
      'slave_load_tmpdir','/tmp'
      'slave_max_allowed_packet','1073741824'
      'slave_net_timeout','3600'
      'slave_parallel_max_queued','131072'
      'slave_parallel_threads','12'
      'slave_skip_errors','OFF'
      'slave_sql_verify_checksum','ON'
      'slave_transaction_retries','10'
      'slave_type_conversions',''
      'slow_launch_time','2'
      'slow_query_log','ON'
      'slow_query_log_file','optosql5-slow.log'
      'socket','/var/lib/mysql/mysql.sock'
      'sort_buffer_size','2097152'
      'sql_auto_is_null','OFF'
      'sql_big_selects','ON'
      'sql_buffer_result','OFF'
      'sql_log_bin','ON'
      'sql_log_off','OFF'
      'sql_mode',''
      'sql_notes','ON'
      'sql_quote_show_create','ON'
      'sql_safe_updates','OFF'
      'sql_select_limit','18446744073709551615'
      'sql_slave_skip_counter','0'
      'sql_warnings','OFF'
      'ssl_ca',''
      'ssl_capath',''
      'ssl_cert',''
      'ssl_cipher',''
      'ssl_crl',''
      'ssl_crlpath',''
      'ssl_key',''
      'storage_engine','InnoDB'
      'stored_program_cache','256'
      'sync_binlog','0'
      'sync_frm','ON'
      'sync_master_info','0'
      'sync_relay_log','0'
      'sync_relay_log_info','0'
      'system_time_zone','CEST'
      'table_definition_cache','400'
      'table_open_cache','512'
      'thread_cache_size','4'
      'thread_concurrency','10'
      'thread_handling','one-thread-per-connection'
      'thread_pool_idle_timeout','60'
      'thread_pool_max_threads','500'
      'thread_pool_oversubscribe','3'
      'thread_pool_size','16'
      'thread_pool_stall_limit','500'
      'thread_stack','294912'
      'time_format','%H:%i:%s'
      'time_zone','SYSTEM'
      'timed_mutexes','OFF'
      'timestamp','1434011008.405971'
      'tmp_table_size','134217728'
      'tmpdir','/tmp'
      'transaction_alloc_block_size','8192'
      'transaction_prealloc_size','4096'
      'tx_isolation','REPEATABLE-READ'
      'tx_read_only','OFF'
      'unique_checks','ON'
      'updatable_views_with_limit','YES'
      'use_stat_tables','NEVER'
      'userstat','OFF'
      'version','10.0.16-MariaDB-log'
      'version_comment','MariaDB Server'
      'version_compile_machine','x86_64'
      'version_compile_os','Linux'
      'version_malloc_library','bundled jemalloc'
      'wait_timeout','28800'
      'warning_count','0'

      The error occurs about once a week during normal operation.

      If you need further information, or if you want us to test something, please let me know.

      Best regards,

      Thomas Mischke

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            • Assignee:
              knielsen Kristian Nielsen
              Reporter:
              thomas.mischke Thomas Mischke
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              • Created:
                Updated:
                Resolved: