expected value after metric, got "MNAME"

[Alen Cappelletti]

Hi all, I got this strange error...

I don't see any error on  my collector (it run from 6 month).

I've just downloaded on my docker app, last version of Prometheus...

but it's the same.

The strange think is that my metric page give me output of data..

So I'm a little bit confused... could be a collector error? Or a prometheus internal err?

• expected value after metric, got "MNAME"

THANKS; Alen

[Brian Candler]

Where *exactly* do you see that error?

What do you see if you scrape your collector directly using curl?

If you save the scrape output, you can validate it with "promtool check metrics"

[Alen Cappelletti]

Thanks Brian for your reply...

I see no error on collector log or on prometheus log...

only from the TARGET (error) page on Prometheus.

I got 7 SQL endpoint.. and I isolate the one with the err.

I see directly from the DB query that 2 row have NULL values?

Could be this?

Now I try with a REPLACE NULL value directly on the query.... but your advise... "If you save the scrape output, you can validate it with "promtool check metrics", it's a good point of view.

I'll be back

Thanks, ALEN

[Brian Candler]

Here are a couple of cases from the prometheus test suite which show bad metrics that give exactly the error you see:

https://github.com/prometheus/prometheus/blob/v2.36.2/model/textparse/promparse_test.go#L220-L223

https://github.com/prometheus/prometheus/blob/v2.36.2/model/textparse/promparse_test.go#L264-L267

A metric name with no value is one of those, so your NULL theory looks likely to be correct.  You could try returning "NaN" for null values.

"promtool check metrics" gives a different error:

# echo "a" | /opt/prometheus/promtool check metrics
error while linting: text format parsing error in line 1: expected float as value, got ""

[Alen Cappelletti]

Yes... it was...

the NULL values.

Now all return run properly.

I've fixed with a classic ISNULL(field, 0) on my query....

THANKS