How do you monitor CouchDB performance using the _stats and _active_tasks endpoints?

CouchDB exposes two key monitoring endpoints out of the box — /_stats and /_active_tasks — which together give a real-time snapshot of server health and ongoing operations.

GET /_stats returns a JSON object of cumulative performance counters organized by category. Key metrics to watch:

• httpd.requests.value — total HTTP requests processed.
• httpd_request_methods.{GET,PUT,POST,DELETE}.value — breakdown by HTTP verb.
• httpd_status_codes.{200,201,400,404,409,500}.value — response code breakdown; rising 409s may indicate conflict storms; rising 500s indicate bugs.
• couchdb.open_databases.value — number of databases currently open (compare to max_dbs_open).
• couchdb.request_time.value — mean, min, max request latency.

curl http://admin:pass@localhost:5984/_stats | python3 -m json.tool | head -60

# On a cluster, query per node:
curl http://admin:pass@localhost:5984/_node/couchdb@node1/_stats

GET /_active_tasks returns a live array of currently running background tasks. Each task has a type field:

• database_compaction — compaction progress as a percentage.
• view_compaction — view index compaction progress.
• indexer — a view index being built or incrementally updated.
• replication — active replication job with checkpoint seq and docs per second.

curl http://admin:pass@localhost:5984/_active_tasks
# [{"type":"indexer","node":"couchdb@node1","design_document":"_design/orders",
#   "view":"by_status","started_on":1700000000,"updated_on":1700000010,
#   "progress":45}]

For production monitoring, both endpoints integrate with Prometheus via the community couchdb-exporter, allowing dashboards in Grafana alongside alerting on queue depth, error rates, and compaction lag.