Lesson 6 — Operations #

Keeping a node healthy: partial updates in place, compaction, the change feed, and reading cluster state. This lesson is server-side — start a node as in Lesson 1 and run the curls against it.

Partial updates in place #

The document update API takes doc (merge), ops (arithmetic), or both:

curl -X POST -H "Authorization: Bearer $KEY" \
  -H 'Content-Type: application/json' \
  -d '{
        "ops": [
          { "op": "incr", "field": "qty", "value": -1 },
          { "op": "min", "field": "price", "value": 9.9 }
        ]
      }' \
  http://localhost:28000/sales/_update/<doc_id>

Eleven operators — set, unset, incr, mul, min, max, toggle, append, add_to_set, rename, current_date — each a column-level write, not a read-modify-write of the whole document. Fields mapped with "inplace": true apply as O(1) column writes; the full semantics (visibility, arithmetic, mixed updates) are in the partial update reference and in-place columns.

No refresh follows: search sees the new values on the next request.

Compaction #

Realtime writes land in a mutable layer; background epochs freeze and merge them. When you want that on demand — after a bulk import, before a benchmark:

curl -X POST -H "Authorization: Bearer $KEY" \
  http://localhost:28000/sales/_compact

The compaction reference covers the response fields; node-level compaction controls live in node settings (pause, tick interval, concurrency).

The change feed #

Consume writes as they happen with GET /{collection}/_changes — the cursor format and consumption loop are in the change feed reference:

curl -H "Authorization: Bearer $KEY" \
  'http://localhost:28000/sales/_changes?limit=10'

Reading the cluster #

• GET /_cluster/health?level=shards — one glance, every level from cluster to shard ( health reference).
• GET /_cluster/state — the catalog view; filter with /_cluster/state/collections,shards.
• GET /_node/_local/stats — per-node counters; the full endpoint map is in node observability.
• GET /_node/_local/settings — dynamic settings, changeable at runtime ( node settings), including the live log level.

Where to go from here #

• The full search reference, one page per query type, every parameter.
• Deployment for systemd, NUMA and multi-node joins.
• The playground to keep experimenting in the browser.