MysQL is frequently going down. Error logs contain:

[ERROR] Missing system table mysql.proxies_priv; please run mysql_upgrade to create it  | 149 occurrences
[ERROR] Native table 'performance_schema'... has the wrong structure                    | 500+

I did a research on the internet. It is suggested to fix it by running a mysql_upgrade script like this:

/etc/init.d/mysqld stop
mysqld_safe --skip-grant-tables &
/etc/init.d/mysqld stop
/etc/init.d/mysqld start

It is strongly advised to create a backup before running any upgrades. But my databases do not look healthy.

There is no snapshot option for this server.


  1. How do I preserve the information?
  2. How would I go about it?
  3. Is it okay to do mysqldumps for such databases?
  • What version do you have? Have you upgraded recently? – ypercubeᵀᴹ Dec 3 '16 at 22:46
  • And what does "But my databases do not look healthy." mean? – ypercubeᵀᴹ Dec 3 '16 at 22:47
  • Version shows as: mysql Ver 14.14 Distrib 5.5.47. The errors above appear in the logs from march, I don't have the earlier log. So probably there was an upgrade before march. – Tomas Morgan Dec 4 '16 at 1:58
  • As I get errors like table ... has the wrong structure they are probably something wrong with them and they are "unhealthy". – Tomas Morgan Dec 4 '16 at 2:00
  • first of all (not clean) - did You run suggested set of command? – a_vlad Dec 4 '16 at 3:53

So I finally fixed it.

I ran upgrade script as described in question.

The logs complained only about the wrong structure of performance_schema which is a system database that contains only performance metrics and a missing proxies_priv table inside other system database.

The errors are gone.

And of course before making any changes I did a backup of all databases with mysqldump.

Thank you all for help! :)

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