Merge Metrics

Metric Name	Type	Components
`merge_success`	Counter	Count of merge successes.
`merge_failure`	Counter	Count of merge successes.
`query_count`	Counter	Merge calls to the Catalog.
`query_failure`	Counter	Merge failed Catalog calls.
`query_latency_summary`	Counter	Latency in calls to catalog.
`query_latency_summary_count/sum`	Counter	Latency in calls to catalog.
`merge_duration_histo_bucket/count/sum`	Histogram	Merge processing duration, in milliseconds.
`merge_duration_summary`	Summary	Merge processing duration, in milliseconds.