PMM2.18 qan-api2 can't start

Percona Monitoring and Management (PMM) PMM 2.x
1

PMM Server run with Docker

[root@a6d103abaf17 supervisord.d]# /usr/sbin/percona-qan-api2 --data-retention=30 --debug  --trace 
stdlog: qan-api2 v2.18.0.
INFO[2021-07-23T03:22:14.109+00:00]qan-api2/main.go:285 main.main Log level: trace.                            
stdlog: dsn:  clickhouse://127.0.0.1:9000?database=pmm&block_size=10000&pool_size=2
stdlog: Migrations: file does not exist

Are these file missing?

2

Are you running PMM server in a non-standard way? You appear to be logged into the container itself which is very very unusual.

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HI matthewb.
I saw that PMM 2.19.0 had a lot of good features, such as adding data monitoring of the proxysql stats_mysql_commands_counters table, so I upgraded from PMM 2.18 to PMM 2.19, but found that collecting stats_mysql_commands_counters led to The sql response time has increased, see Query stats_mysql_commands_counters increase sql response time · Issue #3532 · sysown/proxysql · GitHub if you are interested.
So I downgraded PMM2.19 to PMM2.18. Maybe I did something wrong, I’ve reinstalled PMM2.18 now.

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4

I’m not sure if downgrading PMM is supported. I’ll ask the team. You might be best off by blowing away your 2.19 container and the data container and starting a fresh 2.18.
If you’ve discovered an issue with ProxySQL, I don’t see how downgrading PMM will help.

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5

I’ll have to check on Monday with some of the devs but I’m fairly certain that to downgrade requires a backup and restore of data pre-upgrade. Restoring an old application on the newer data will certainly have config and data changes and the old version will not know what to do with them.

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Yep, as expected rollback isn’t supported due to constraints by each of the individual technologies PLUS some of the routines we run on the DBs to allow for the changes in each new version. In order to revert you must first take a backup of your data volume then if you want to go back you need to install the original version of pmm and perform a restore of the backup. Here is a link specific for backups and restores that should help for next time!

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