Is there a reason why query is not being sent to the queryHistogram (metric recording)

[jairomfj]

The following piece of code creates an attrs array, appends the formatted query and sends the newly created array to the trace. On the other hand, the query is not sent when recording the queryHistogram.

	...

	attrs := make([]attribute.KeyValue, 0, len(t.attrs)+1)
	attrs = append(attrs, t.attrs...)
	if query != "" {
		attrs = append(attrs, semconv.DBStatementKey.String(t.formatQuery(query)))
	}

	ctx, span := t.tracer.Start(ctx, spanName,
		trace.WithSpanKind(trace.SpanKindClient),
		trace.WithAttributes(attrs...))
	err := fn(ctx, span)
	span.End()

	if query != "" {
		// t.attrs does not contain the query
		t.queryHistogram.Record(ctx, time.Since(startTime).Milliseconds(), metric.WithAttributes(t.attrs...)) 
	}

source: https://github.com/uptrace/opentelemetry-go-extra/blob/main/otelsql/otel.go#L94-L108

[vmihailenco]

Because high-cardinality attributes are best to be avoided in metrics.

[jairomfj]

Hi @vmihailenco , thank you for the reply!

I was wondering whether it would make sense to add some formatting for that? Something that would simplify the query to some sort of OPERATION table? E.g.:

• INSERT table
• SELECT table
• etc

I know this won't map all the possible queries depending on the complexity, but for simpler scenarios it could be helpful.

Do you think something like it would make sense?

[vmihailenco]

@jairomfj yes, that makes sense, but it is not trivial to extract that information from queries. PR is welcome though :)