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Dan RammerandClaude Opus 5
fe34eb3549
## What Renames the MemWAL surface in two passes, across Rust, Python, TypeScript, and Java, including the wire format. ### 1. MemWAL APIs drop "LSM" The write path these APIs drive is Lance's MemWAL; "LSM" described its shape rather than naming it. Turning it on and off now reads as enabling a feature rather than installing a spec. | Before | After | |---|---| | `set_lsm_write_spec` | `enable_memwal` | | `unset_lsm_write_spec` | `disable_memwal` | | `get_lsm_write_spec` | `get_memwal_spec` | | `flush_lsm` / `compact_lsm` / `checkpoint_lsm` | `flush_memwal` / `compact_memwal` / `checkpoint_memwal` | | `get_lsm_stats` | `get_memwal_stats` | | `close_lsm_writers` | `close_memwal_writers` | | `use_lsm` (query, merge insert) | `use_memwal` | | `LsmWriteSpec` / `LsmStats` | `MemWalWriteSpec` / `MemWalStats` | | Java `LanceDbTableLsm` | `LanceDbTableMemWal` | TypeScript and Java use camelCase (`enableMemWal`, `getMemWalStats`, ...); the napi methods set `js_name` so the generated names keep the `MemWal` casing. flush/compact/checkpoint keep a `_memwal` suffix so `compact_memwal` is not confused with `compact_files` / `optimize`, which compact the base table. Internal names (`LsmMode`, `LsmScanner`, the `merge::lsm` / `query::lsm` modules) are unchanged. ### 2. Stats use SSTable and table shard Aligns the stats surface with the MemWAL naming settled upstream in lance-format/lance#7943 and #7957, where the persisted unit became an **SSTable**. **Generation → SSTable.** A `GenerationStats` describes one flushed MemTable, which is an SSTable. The generation *number* is kept — an SSTable is identified by its generation — so only the noun moved. **Bucket → table shard.** Each entry is one MemWAL shard. "Bucket" names only the hash sharding *transform*, so it was already wrong for `identity` and `year` sharding, which produce shards and no buckets at all. | Before | After | |---|---| | `GenerationStats` | `SsTableStats` | | `BucketStats` | `TableShardStats` | | `stats.buckets` | `stats.table_shards` | | `BucketStats.generations` | `TableShardStats.sstables` | | `include_generation_rows` | `include_sstable_rows` | | `newest_generation` | `newest_sstable_generation` | | `outstanding_generations` | `outstanding_sstables` | Docs and comments follow suit: "seal" → "freeze", "L0" / "flushed generations" → SSTables, "bucket" (meaning a shard) → table shard. `MemWalWriteSpec::bucket`, `num_buckets`, and the `"Sealed"` shard status value are **unchanged** — those name the sharding transform or a server value, not the shard. ## Compatibility Breaking, for an experimental API. The wire format changes with the SDKs, so this must roll out together with the matching server change: - Routes: `/set_lsm_write_spec/` → `/enable_memwal/`, `/unset_lsm_write_spec/` → `/disable_memwal/`, `/get_lsm_write_spec/` → `/get_memwal_spec/`, `/flush_lsm/` → `/flush_memwal/`, `/compact_lsm/` → `/compact_memwal/`, `/get_lsm_stats/` → `/get_memwal_stats/` - Response keys: `lsm_write_spec` → `memwal_spec`, `lsm_stats` → `memwal_stats`, `buckets` → `table_shards`, `generations` → `sstables` - Request fields: `include_generation_rows` → `include_sstable_rows`; `use_lsm` → `use_memwal` on query and merge-insert bodies ## Validation - Rust: `cargo test --features remote -p lancedb --lib --tests` — 1467 lib tests and all integration test targets pass; `cargo clippy` clean - Python: rebuilt the extension; `test_remote_db`, `test_memwal_spec`, `test_merge_insert_lsm`, `test_query`, `test_permutation`, `test_table` — 655 passed; `ruff format` / `ruff check` clean - TypeScript: `pnpm build`; `table`, `merge`, `query` tests — 593 passed; `biome check` clean; `docs/src/js` regenerated with `npm run docs` - Java: `mvn test` — 37 passed (Spotless applied with JDK 11; the pinned google-java-format does not run on JDK 21) 🤖 Generated with [Claude Code](https://claude.com/claude-code) --------- Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
LanceDB JavaScript SDK
A JavaScript library for LanceDB.
Installation
npm install @lancedb/lancedb
This will download the appropriate native library for your platform. We currently support:
- Linux (x86_64 and aarch64 on glibc and musl)
- MacOS (Intel and ARM/M1/M2)
- Windows (x86_64 and aarch64)
Usage
Basic Example
import * as lancedb from "@lancedb/lancedb";
const db = await lancedb.connect("data/sample-lancedb");
const table = await db.createTable("my_table", [
{ id: 1, vector: [0.1, 1.0], item: "foo", price: 10.0 },
{ id: 2, vector: [3.9, 0.5], item: "bar", price: 20.0 },
]);
const results = await table.vectorSearch([0.1, 0.3]).limit(20).toArray();
console.log(results);
The quickstart contains more complete examples.
Development
See CONTRIBUTING.md for information on how to contribute to LanceDB.