Upgrade to 1.6.1 leads to slave_Seconds_Behind_Master no longer being populated.

[nsteinmetz]

As i said on slack: since upgrade to Telegraf 1.6.1 (from 1.5.3), I lost the slave_Seconds_Behind_Master. Other change I made was on InfluxDB side to upgrade from 1.5.1 to 1.5.2.

All the other data I use seems there.

Relevant telegraf.conf:

Original setup :

[[inputs.mysql]]
servers = ["telegraf:REDACTED@unix(/var/run/mysqld/mysqld.sock)/"]
table_schema_databases = []
gather_table_schema = true
gather_user_statistics = true
gather_process_list = true
gather_slave_status = true
gather_innodb_metrics = true

With the new metric:

[[inputs.mysql]]
servers = ["telegraf:REDACTED@unix(/var/run/mysqld/mysqld.sock)/"]
table_schema_databases = []
gather_table_schema = true
gather_user_statistics = true
gather_process_list = true
gather_slave_status = true
gather_innodb_metrics = true

[[inputs.mysql]]
name_suffix= "_2"
metric_version = 2

servers = ["telegraf:REDACTED@unix(/var/run/mysqld/mysqld.sock)/"]
table_schema_databases = []
gather_table_schema = true
gather_user_statistics = true
gather_process_list = true
gather_slave_status = true
gather_innodb_metrics = true

System info:

Telegraf version : 1.6.1
Debian 9.x Stretch up to date 64 bits
MariaDB 10.1.25

Steps to reproduce:

Till I did the upgrade:

> SELECT last("slave_Seconds_Behind_Master") FROM "mysql" WHERE ("host" = 'codb2d9')
name: mysql
time                last
----                ----
1525419720000000000 0

Timestamp is when I did the upgrade. No more entry since.

After upgrading metric, no data either

> SELECT last("slave_Seconds_Behind_Master") FROM "mysql" WHERE ("host" = 'codb2d9')
name: mysql
time                last
----                ----
1525419720000000000 0
> SELECT last("slave_Seconds_Behind_Master") FROM "mysql_2" WHERE ("host" = 'codb2d9')
>

Expected behavior:

Having updated values for slave_Seconds_Behind_Master

Actual behavior:

No value for slave_Seconds_Behind_Master

Additional info:

   Loaded: loaded (/lib/systemd/system/telegraf.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2018-05-04 10:42:32 CEST; 3h 45min ago
     Docs: https://github.com/influxdata/telegraf
 Main PID: 17352 (telegraf)
    Tasks: 24 (limit: 4915)
   CGroup: /system.slice/telegraf.service
           └─17352 /usr/bin/telegraf -config /etc/telegraf/telegraf.conf -config-directory /etc/telegraf/telegraf.d

May 04 14:23:00 codb2d9 telegraf[17352]: 2018-05-04T12:23:00Z E! MySQL Error gathering user stats: Error 1054: Unknown column 'rows_fetched' in 'field list'
May 04 14:24:00 codb2d9 telegraf[17352]: 2018-05-04T12:24:00Z E! MySQL Error gathering user stats: Error 1054: Unknown column 'rows_fetched' in 'field list'
May 04 14:25:00 codb2d9 telegraf[17352]: 2018-05-04T12:25:00Z E! MySQL Error gathering user stats: Error 1054: Unknown column 'rows_fetched' in 'field list'
May 04 14:25:00 codb2d9 telegraf[17352]: 2018-05-04T12:25:00Z E! MySQL Error gathering user stats: Error 1054: Unknown column 'rows_fetched' in 'field list'
May 04 14:26:00 codb2d9 telegraf[17352]: 2018-05-04T12:26:00Z E! MySQL Error gathering user stats: Error 1054: Unknown column 'rows_fetched' in 'field list'
May 04 14:26:00 codb2d9 telegraf[17352]: 2018-05-04T12:26:00Z E! MySQL Error gathering user stats: Error 1054: Unknown column 'rows_fetched' in 'field list'
May 04 14:27:00 codb2d9 telegraf[17352]: 2018-05-04T12:27:00Z E! MySQL Error gathering user stats: Error 1054: Unknown column 'rows_fetched' in 'field list'
May 04 14:27:00 codb2d9 telegraf[17352]: 2018-05-04T12:27:00Z E! MySQL Error gathering user stats: Error 1054: Unknown column 'rows_fetched' in 'field list'
May 04 14:28:00 codb2d9 telegraf[17352]: 2018-05-04T12:28:00Z E! MySQL Error gathering user stats: Error 1054: Unknown column 'rows_fetched' in 'field list'
May 04 14:28:00 codb2d9 telegraf[17352]: 2018-05-04T12:28:00Z E! MySQL Error gathering user stats: Error 1054: Unknown column 'rows_fetched' in 'field list'```

But seems related to #2910.

[nsteinmetz]

Ok got it just now - it's all in lower case now slave_seconds_behind_master

[danielnelson]

@nsteinmetz Thanks for the heads up, I'm going to keep this as is with metric_version = 2, but revert the change with the original config. Sorry about the confusion.