Store kinds

Everything Vike Trader keeps on disk as history lives under a store root in a kind= path segment, and that segment is a contract between two ends that never meet: the live recorder, the property and chain recorders, the backfill collectors and the journal materializer on one side; tick replay, the reads a data node serves, and the Data Manager and Studio inventory views on the other. crates/vike-data/src/store_kind.rs's STORE_KINDS is where that contract is written down — one row per stored kind, thirteen of them today, each with its own page here. That producer list is illustrative and not a census: a producer is anything holding a HistStore, so the header declines to claim any list can be complete.

Until that file existed, no site named the contract, and its header records what that cost. crates/vike-data/src/coverage.rs's TICK_KINDS was missing depth, so a whole kind was invisible to the cross-kind coverage report while its rows sat on disk. Five Data Manager verbs built their path from SeriesId::symbol, which is empty for a grouped series, so each silently operated on a series that does not exist — delete was a no-op that returned Ok(()).

What a row declares

One StoreKind names the domain type a decoded row becomes, every Arrow column today's writer emits in schema order with the series_codec! flavor that picks its type and nullability, the Parquet schema-metadata key the kind stamps when it stamps one, how the leaf is partitioned, whether a grouped form exists, what venue and symbol actually mean for that kind, and the commit-key shapes its known producers use.

Two column flavors bite a consumer. A _null column is always present and may hold SQL NULL; an _add column may be absent entirely from a part sealed before it was added, because the _add flavors read through an absent-tolerant column reader. A kind's columns are what today's writer emits, so nothing may assume an _add column is present in an old part.

Partitioning, stated once

Parts are date=-partitioned identically for every kind — <series leaf>/date=YYYY-MM-DD/ — so no per-kind page repeats it. What the partition guarantees is that a part never spans a UTC day: crates/vike-data/src/datafusion_hist/manifest.rs's seal_into_manifest groups a batch's rows by day and seals one part per group.

Below the shared kind=…/venue=… prefix the leaf has two spellings. The per-symbol form is symbol=…, and bar alone adds interval=… beneath it so a 1m and a 1d series of one instrument never interleave — the table's only Partition::SymbolInterval row. The grouped form is kind=…/venue=…/group=…, written by DataFusionHist's group_dir, where one part holds many symbols told apart by the row-level symbol_col column. The two are siblings under one parent and a store can hold both at once, so anything building or parsing a path must branch on group first — series_dir_of is the one function that does it correctly, and the five verbs that did not are the incident above. In the same vein, SeriesId::symbol is empty for a grouped series, SeriesId::group carries the name, and SeriesId::label answers for both.

Declare today's reality; pin the contradictions

The table is step one of the workspace's two-step playbook for a capability table: it merged byte-identical in behaviour and writes down what the code does today, including where two sites disagree. Each disagreement is named in a row's notes with both sides cited, and a test asserts it still exists, so whoever resolves one is told to update the table rather than leave a stale warning behind. Two rows carry such a note today. The depth row's is labelled a pinned contradiction: crates/vike-backfill/src/regroup.rs's GROUPABLE_KINDS lists depth as having a grouped form and the store has none. The funding row's is labelled a pinned name collision — two unrelated series are called funding: kind=funding is the account's realized payments, while the market funding-rate history is a bar series under the reserved interval=funding label, carrying the rate on Bar::funding with OHLCV and volume all zero.

The gate's pinned section holds four tests, not two. The other pair pins no row disagreement: both_depth_defaults_refuse and both_catalog_defaults_refuse hold append_depth/scan_depth, and list_series/inventory, to an Err rather than a fabricated empty read.

This is deliberately not schema versioning. crates/vike-data/src/store_kind.rs's header is emphatic about the difference and says versioning must stay deferred: a row records a metadata key a kind already writes, and introduces no version negotiation, no migration and no new on-disk byte.

The gate

crates/vike-data/tests/store_kind_gate.rs derives the live kind set from the code and fails until a row exists — three independent derivations, because each is blind to a different mistake: the kind= segments the store actually writes, read off the first argument of every series_dir/ticks_dir/group_dir call in the backend module tree; the strings each compaction dispatch accepts, each dispatch checked on its own; and the fn append_* verbs on the always-compiled HistStore trait, which reddens first when a kind is added the ordinary way. Shape is gated separately, by parsing the series_codec! invocations and comparing each row's columns and schema-metadata key against the field list they were read from. Every check reads source text on purpose — the codecs sit behind the hist-datafusion feature while the test runs in the default lane, and regroup.rs is in a crate vike-data cannot depend on.

Two residuals are declared, and the declaration is the point. Dataflow is not followed, and that is measured: a SeriesId with kind: "oracle" handed to the declared series_dir_of site builds a kind=oracle directory with no compaction arm and no append verb while the gate stays at 25 passed, 0 failed. And the scope is this crate's src — another crate holding a store root can build a directory with a plain join, and a store written by a newer build already holds kinds no source here mentions.

The thirteen kinds

Four line up in the cross-kind coverage report — TICK_KINDS is trade, quote, book and depth. Three kind ids carry underscores on disk (exec_fill, exec_order, perp_metrics) where their page slugs use hyphens. Most seam verbs state their own default on the trait method; the one pair worth carrying here is depth, where both append_depth and scan_depth return an Err in a store that does not implement them, because a store with no depth lane and a store with no depth rows must not read identically to a caller.

bar · quote · trade · book · depth · properties · equity · exec-fill · exec-order · funding · chain · cohort · perp-metrics

The seam itself, and where a store root resolves when nobody says, are on The history store; its live mirror is the live data seam. What fills a store is data providers and store maintenance; what reads it back is tick replay and the Data Manager's coverage view.