# The store's own metrics A store can measure itself into its own `metrics.db`: its commits and how long writes wait for them, its files' sizes, its memory, the machine it runs on, and each engine's own counts. A program reads them as it reads its own series, for a dashboard of the store with no Prometheus beside it. It is off unless asked for. ```ts const store = await open('./data', { selfMetrics: true }) const alone = await open('./data', { selfMetrics: { system: false } }) // the machine left out ``` ```python store = await tinystore.open("./data", self_metrics=True) alone = await tinystore.open("./data", self_metrics={"system": False}) ``` ```go store, err := tinystore.Open(ctx, "./data", tinystore.SelfMetrics()) alone, err := tinystore.Open(ctx, "./data", tinystore.SelfMetrics(tinystore.WithoutSystem())) ``` ```rust let store = Store::open("./data", Options { self_metrics: Some(SelfMetrics::default()), ..Options::default() })?; let alone = SelfMetrics { system: false }; ``` ```sh tinystore serve ./data --self-metrics ``` Then read them as any series: ```ts const slow = await store.metrics.aggregate({ name: 'tinystore_commit_ms', since: '1h', every: '1m', op: 'max', by: ['file'] }) ``` ```python slow = await store.metrics.aggregate(name="tinystore_commit_ms", since="1h", every="1m", op="max", by=["file"]) ``` ```go slow, err := metrics.Aggregate(ctx, store, metrics.Query{Name: "tinystore_commit_ms", Since: time.Hour, Every: time.Minute, Op: metrics.Max, By: []string{"file"}}) ``` ```rust let slow = store .metrics()? .query() .name("tinystore_commit_ms") .since(Duration::from_hours(1)) .every(Duration::from_mins(1)) .by(&["file"]) .aggregate(Op::Max)?; ``` ## The store, SQLite and the writer | Name | Kind | Labels | What it is | | ------------------------------------- | ------- | ------ | ----------------------------------------------------- | | `tinystore_commits_total` | counter | `file` | commits of the file's writer | | `tinystore_commit_writes_total` | counter | `file` | the writes they carried; over commits, a group's size | | `tinystore_commit_ms` | timer | `file` | a commit, its sync included | | `tinystore_writer_wait_ms` | timer | `file` | a write from its queueing to its commit's begin | | `tinystore_file_bytes` | gauge | `file` | the file's size | | `tinystore_wal_bytes` | gauge | `file` | its write-ahead log's size | | `tinystore_readers_open` | gauge | `file` | its read connections open | | `tinystore_memory_used_bytes` | gauge | | what the store's work holds of its memory budget | | `tinystore_memory_limit_bytes` | gauge | | the budget | | `tinystore_disk_free_bytes` | gauge | | the disk's free space under the directory | | `tinystore_background_failures_total` | counter | `task` | failures of the store's periodic work | `file` is `kv`, `jobs`, `records`, `metrics`, `search`, and `sql/` for a database: the first 32 databases a store opens are named, and every one after them counts into `sql/__overflow`. ## The machine Unless `system: false`: | Name | What it is | | ----------------------------------------- | ------------------------------------------------------------ | | `tinystore_process_memory_bytes` | the process's resident memory | | `tinystore_process_cpu_percent` | its processor use, 100 a core | | `tinystore_system_memory_bytes` | the system's memory | | `tinystore_system_memory_available_bytes` | what of it is available | | `tinystore_system_cpu_percent` | every core's use together, 100 all busy | | `tinystore_system_core_cpu_percent` | each core's, labelled `core` | | `tinystore_system_load` | load over `1m`, `5m`, `15m`, labelled `span`; not on Windows | A processor's use is counted between two reads, so its gauges begin 15 seconds after the store opens. In a container they read the container's. ## Each engine's | Name | What it is | | ------------------------------------------------------------------------------------- | ----------------------------------------- | | `tinystore_jobs_completed_total`, `_failed_total`, `_retried_total` | jobs by `queue` | | `tinystore_jobs_run_ms` | a run, from its claim to its end | | `tinystore_jobs_claim_delay_ms` | how late a claim took a job past its time | | `tinystore_jobs_waiting`, `_running` | jobs waiting, and held | | `tinystore_kv_expired_total` | keys deleted once they expired | | `tinystore_records_events_total` | events appended, by `stream` | | `tinystore_records_lines_dropped_total` | a logger's lines dropped | | `tinystore_channels_published_total`, `_delivered_total`, `_missed_total` | by `channel` | | `tinystore_locks_wait_ms`, `tinystore_locks_busy_total`, `tinystore_locks_lost_total` | by `lock` | | `tinystore_search_ms` | a search, by `index` | | `tinystore_blobs_written_total`, `_read_total`, `_damaged_total` | files, and their bytes | | `tinystore_wire_requests_total`, `tinystore_wire_call_ms` | requests by `method`, `kv.get` | | `tinystore_replication_ack_wait_ms` | a synchronous home's wait for a copy | An engine's labels name its first 32 values, and every value after them counts into `__overflow`. A label is never what a program gives at a call: no key, no SQL, no job's id, no path. ## How it is measured - Through the instruments: counters, gauges and timers kept in memory and written with the program's own every 15 seconds. No measurement opens a transaction, and a measurement never fails a write. - The metrics engine's own writes of its totals are not measured, so the store does not measure itself measuring. - Names that start with `tinystore_` are the store's: an instrument or an `ingest` of the program's that writes one is `invalid`. ## Cost Off, a write pays one check of an empty cell. On, in a write-heavy run of kv's `set` of 20,000 keys from 1, 8 and 64 threads, the median of five passes, `durability: os` (Windows 11 Pro, AMD Ryzen 7 7700, 31 GiB, release build, 19 October 2026), one thread ran within 1 % of off, and with more threads the passes moved 6 % either way, on not the slower of the two. Linux and macOS were not measured. ```sh cargo test --release -p tinystore --lib probe::probe_tests::sets_measured_and_not -- --ignored --nocapture ``` ## See also - [Metrics](https://tinyshed.org/tinystore/docs/guides/metrics): the engine's overview. - [Aggregates](https://tinyshed.org/tinystore/docs/guides/metrics/aggregates): reading these series. - [Running it](https://tinyshed.org/tinystore/docs/handbook/production/running-it) in the Handbook.