Usability of batch inserts for Map type

[nikita-vanyasin]

A minor usability issue report.

The next code

for _, alert := range alerts {
	labels := alert.Labels
	annotations := alert.Annotations
	batch.Append(
		alert.Status, alert.StartsAt, alert.EndsAt, alert.GeneratorURL, alert.Fingerprint, labels, annotations,
		labels["env"], labels["cloud"], labels["region"], labels["cell"], labels["team"], labels["alertname"], labels["namespace"],
	)
}
return batch.Send()

Fails with:

batch is invalid. check appended data is correct: clickhouse [AppendRow]: labels clickhouse [AppendRow]: converting template.KV to Map(String, String) is unsupported. try using map[string]string

If we explicitly cast to map types, it works fine:

for _, alert := range alerts {
	// type casts are mandatory as batch.Append can't handle KV type
	labels := map[string]string(alert.Labels)
	annotations := map[string]string(alert.Annotations)
	batch.Append(
		alert.Status, alert.StartsAt, alert.EndsAt, alert.GeneratorURL, alert.Fingerprint, labels, annotations,
		labels["env"], labels["cloud"], labels["region"], labels["cell"], labels["team"], labels["alertname"], labels["namespace"],
	)
}
return batch.Send()

Given that template.KV type is defined as type KV map[string]string, I think it should be possible to just pass it as-is to Append without explicit cast.

[SpencerTorres]

The driver uses a lot of reflection to determine and iterate types. With the specific samples you provided, I believe the Go specification on type identity is relevant:

https://go.dev/ref/spec#Type_identity

Sure we could probably solve this with reflection, but it's a fair performance tradeoff to simply prefer a standard map in this case.