[debian-mysql] Bug#910454: Bug#910454: mysql-server: Restoring backup hangs for a large database

[Olaf van der Spek]

Hi Matthew,

What does mytop or "show processlist" say?

> mysqldump --databases mythconverg > dump.myth

mysqldump mythconverg is simpler, the name of the database won't be
included in the file so you can more easily restore it to a different
name.

Gr,

Olaf

On Sat, Oct 6, 2018 at 4:59 PM, Matthew Toseland <toad at toselandcs.co.uk> wrote:
> Package: mysql-server
> Version: 5.5.9999+default
> Severity: normal
>
> Dear Maintainer,
>
> I am unable to restore a backup of a large database. Here I was
> attempting to copy it by backing it up and restoring it.
>
> What I did:
>
> $ mysqldump --databases mythconverg > dump.myth
> $ vi dump.myth
> # Change the first few lines to change the name of the database from
> # mythconverg to mythcopy and not fail if it already exists
> $ mysql
> MariaDB [(none)]> create database mythcopy;
> MariaDB [(none)]> use mythcopy;
> MariaDB [(none)]> source dump.myth;
> ...
> Query OK, 21749 rows affected (0.22 sec)
> Records: 21749  Duplicates: 0  Warnings: 0
> ...
> Query OK, 21767 rows affected (0.20 sec)
> Records: 21767  Duplicates: 0  Warnings: 0
>
> There are lots of query records like the above, then it just stops, and
> hangs for at least half an hour, probably forever.
>
> I am able to use the mysql command line client on other databases, but not
> on mythcopy. mysqld is not using any significant CPU or disk I/O according
> to top and iotop. And /var/lib/mysql is on an SSD.
>
> Googling shows a few bugs in the MySQL bug tracker, but nothing obvious
> w.r.t. MariaDB, so there may be an upstream fix in MySQL but not
> necessarily in  MariaDB.
>
> -- System Information:
> Debian Release: 9.5
>   APT prefers stable
>   APT policy: (500, 'stable')
> Architecture: amd64 (x86_64)
> Foreign Architectures: i386
>
> Kernel: Linux 4.9.0-8-amd64 (SMP w/6 CPU cores)
> Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB.UTF-8 (charmap=UTF-8)
> Shell: /bin/sh linked to /bin/bash
> Init: systemd (via /run/systemd/system)
>
> Versions of packages mysql-server depends on:
> ii  default-mysql-server  1.0.2
>
> mysql-server recommends no packages.
>
> mysql-server suggests no packages.
>
> -- debconf-show failed
>
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-- 
Olaf