Re: Lost connection to MySQL server during query

[Christopher Popplewell]

mysql> select ifnull(engine,'TOTALS') as storage_engine, round(data/1024/1024,1) as dataMB, round(idx/1024/1024,1) as idxMB, round((data+idx)/1024/1024,1) as totalMB from ( select engine, sum(data_length) as data, sum( index_length) as idx from information_schema.tables where engine not in('information_schema','performance_schema') and engine is not null group by engine with rollup ) sums order by storage_engine;
ERROR 2013 (HY000): Lost connection to MySQL server during query

mysql> SELECT 1; ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 1
Current database: *** NONE ***

+---+
| 1 |
+---+
| 1 |
+---+
1 row in set (0.00 sec)

mysql> SELECT 1;
+---+
| 1 |
+---+
| 1 |
+---+
1 row in set (0.00 sec)


###############
# I cleared the .err file because it was growing so rapidly. Then I ran the above and this is what it immediately produced:

2017-11-14 19:46:50 24784 [Note] Plugin 'FEDERATED' is disabled.
2017-11-14 19:46:50 24784 [Note] InnoDB: Using atomics to ref count buffer pool pages
2017-11-14 19:46:50 24784 [Note] InnoDB: The InnoDB memory heap is disabled
2017-11-14 19:46:50 24784 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2017-11-14 19:46:50 24784 [Note] InnoDB: Memory barrier is not used
2017-11-14 19:46:50 24784 [Note] InnoDB: Compressed tables use zlib 1.2.3
2017-11-14 19:46:50 24784 [Note] InnoDB: Using Linux native AIO
2017-11-14 19:46:50 24784 [Note] InnoDB: Using CPU crc32 instructions
2017-11-14 19:46:50 24784 [Note] InnoDB: Initializing buffer pool, size = 128.0M
2017-11-14 19:46:50 24784 [Note] InnoDB: Completed initialization of buffer pool
2017-11-14 19:46:50 24784 [Note] InnoDB: Highest supported file format is Barracuda.
2017-11-14 19:46:50 24784 [Note] InnoDB: The log sequence numbers 94329373833 and 94329373833 in ibdata files do not match the log sequence number 94329462860 in the ib_logfiles!
2017-11-14 19:46:50 24784 [Note] InnoDB: Database was not shutdown normally!
2017-11-14 19:46:50 24784 [Note] InnoDB: Starting crash recovery.
2017-11-14 19:46:50 24784 [Note] InnoDB: Reading tablespace information from the .ibd files...
2017-11-14 19:46:51 24784 [Note] InnoDB: Restoring possible half-written data pages
2017-11-14 19:46:51 24784 [Note] InnoDB: from the doublewrite buffer...
2017-11-14 19:46:51 24784 [Note] InnoDB: 128 rollback segment(s) are active.
2017-11-14 19:46:51 24784 [Note] InnoDB: Waiting for purge to start
2017-11-14 19:46:51 24784 [Note] InnoDB: 5.6.38 started; log sequence number 94329462860
2017-11-14 19:46:51 24784 [Note] Server hostname (bind-address): '*'; port: 3306
2017-11-14 19:46:51 24784 [Note] IPv6 is not available.
2017-11-14 19:46:51 24784 [Note] - '0.0.0.0' resolves to '0.0.0.0';
2017-11-14 19:46:51 24784 [Note] Server socket created on IP: '0.0.0.0'.
2017-11-14 19:46:51 24784 [Note] Event Scheduler: Loaded 0 events
2017-11-14 19:46:51 24784 [Note] /usr/sbin/mysqld: ready for connections.
Version: '5.6.38' socket: '/var/lib/mysql/mysql.sock' port: 3306 MySQL Community Server (GPL)