# brk_store
Key-value storage layer built on fjall for Bitcoin indexing.
## What It Enables
Persist and query Bitcoin index data (address→outputs, txid→height, etc.) with access patterns optimized for different workloads: random lookups, sequential scans, and recent-data queries.
## Key Features
- **Workload-optimized configs**: `Kind::Random` (bloom filters, pinned blocks), `Kind::Recent` (point-read optimized), `Kind::Sequential` (scan-friendly), `Kind::Vec` (append-heavy)
- **Write batching**: Accumulate puts/deletes in memory, commit atomically
- **Tiered caching**: In-memory LRU cache layers before hitting disk
- **Version management**: Automatic schema versioning with `StoreMeta`
- **Height-aware operations**: `insert_if_needed` / `remove_if_needed` skip work at heights already processed
## Core API
```rust,ignore
let store: Store<Txid, Height> = Store::import(
&db, &path, "txid_to_height",
Version::new(1), Mode::Any, Kind::Random
)?;
store.insert(txid, height);
store.commit(height)?;
let height = store.get(&txid)?;
```
## Access Patterns
| `Random` | UTXO lookups, txid queries | Aggressive bloom filters |
| `Recent` | Mempool, recent blocks | Point-read hints |
| `Sequential` | Full chain scans | Minimal indexing |
| `Vec` | Append-only series | Large memtables, no filters |
## Built On
- `brk_error` for error handling
- `brk_types` for `Height`, `Version`