Mysql-error during installation of calendar-app nextcloud 20.0.8

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1

Maybe someone could help me understanding a MySQL-error-message.

When I try to install the calendar-app from within the nextcloud-admin-interface, I get this error:

An exception occured while executing 'SELECT DISTINCT 
k.`CONSTRAINT_NAME`,
k.`COLUMN_NAME`,
k.`REFERENCED_TABLE_NAME`,
k.`REFERENCED_COLUMN_NAME`/*!50116,
c.update_rule, c.delete_rule */ FROM 
information_schema.key_column_usage k /*!50116 
INNER JOIN 
information_schema.referential_constraints c ON 
c.constraint_name = k.contstraint_name AND 
c.table_name = 'oc_documents_op' */ WHERE
k.table_name = 'oc_documents_op' AND 
k.table_schema = 'nextcloud' /*!50116 AND
c.contstraint_schema = 'nextcloud' */ AND 
k.`REFERENCED_COLUMN_NAME` is not NULL':
SQLSTATE[HY000]: General error: 2006 MySQL server gone away

What does this mean and what should be the next steps to solve this problem?

2

You have to Google this error. Looks something running unstable. Upgrade your server or restart it.

3

Hi Morta, thanks for your answer!

I found out that I’m using MariaDB version 5.5.68. When I try to install the calendar app, the mariadb.log shows the following:

InnoDB: Error: tried to read 16384 bytes at offset 0 12713984.
InnoDB: Was only able to read 12288.
0204 23:28:37  InnoDB: Operating system error number 5 in a file operation.
InnoDB: Error number 5 means 'Input/output error'.
InnoDB: Some operating system error numbers are described at
InnoDB: http://dev.mysql.com/doc/refman/5.5/en/operating-system-error-codes.html
InnoDB: File operation call: 'read'.
InnoDB: Cannot continue operation.
220204 23:28:37 mysqld_safe Number of processes running now: 0
220204 23:28:38 mysqld_safe mysqld restarted
220204 23:28:38 [Note] /usr/libexec/mysqld (mysqld 5.5.68-MariaDB) starting as process 5231 ...
220204 23:28:38 InnoDB: The InnoDB memory heap is disabled
220204 23:28:38 InnoDB: Mutexes and rw_locks use GCC atomic builtins
220204 23:28:38 InnoDB: Compressed tables use zlib 1.2.7
220204 23:28:38 InnoDB: Using Linux native AIO
220204 23:28:38 InnoDB: Initializing buffer pool, size = 128.0M
220204 23:28:38 InnoDB: Completed initialization of buffer pool
220204 23:28:38 InnoDB: highest supported file format is Barracuda.
InnoDB: The log sequence number in ibdata files does not match
InnoDB: the log sequence number in the ib_logfiles!
InnoDB: Restoring possible half-written data pages from the doublewrite buffer...
220204 23:28:38  InnoDB: Waiting for the background threads to start
220204 23:28:39 Percona XtraDB (http://www.percona.com) 5.5.61-MariaDB-38.13 started; log sequence number 12189548202
220204 23:28:39 [Note] Plugin 'FEEDBACK' is disabled.
220204 23:28:39 [Note] Server socket created on IP: '0.0.0.0'.
220204 23:28:39 [Note] Event Scheduler: Loaded 0 events
220204 23:28:39 [Note] /usr/libexec/mysqld: ready for connections.
Version: '5.5.68-MariaDB'  socket: '/var/lib/mysql/mysql.sock'  port: 3306  MariaDB Server

Since it’s an input/output error (see line 4 above), I checked the relevant file systems with no problems.

4

InnoDB: Error: tried to read 16384 bytes at offset 0 12713984.
InnoDB: Was only able to read 12288.

You have to increase the bytes to read. You must Google how to make it. That is a configuration error and limitation

5

I was able to enalarge innodb_buffer_pool_size to 1GB. This is confirmed:

MariaDB [(none)]> select @@innodb_buffer_pool_size;
+---------------------------+
| @@innodb_buffer_pool_size |
+---------------------------+
|                1073741824 |
+---------------------------+

This IT-Blog and that MySQL-Reference were helpful.

After restarting mysql-server and trying to install calendar-app again the same both error-messages within nextcloud and the mariadb.log appeared again.

Furthermore I could find out that the error in mariadb.log couldt be reproduced with one of these actions:

  1. Using nextcloud database in mysql and then executing: show tables; 
   Database changed
   MariaDB [nextcloud]> show tables;
   ERROR 2006 (HY000): MySQL server has gone away
   No connection. Trying to reconnect...
   Connection id:    1
   Current database: nextcloud
   ERROR 2006 (HY000): MySQL server has gone away
   No connection. Trying to reconnect...
   ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql /mysql.sock' (111)
   ERROR: Can't connect to the server
  1. Executing mysqlcheck nextcloud
    mysqlcheck: Got error: 2013: Lost connection to MySQL server during query when executing 'CHECK TABLE ... '

Seems, that increasing innodb_buffer_pool_size is not related to my problem. What else could I check? Thanks a lot!