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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>
92 lines
2.6 KiB
Markdown
92 lines
2.6 KiB
Markdown
# LanceDB Java Enterprise Client
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## Configuration and Initialization
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### LanceDB Cloud
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For LanceDB Cloud, use the simplified builder API:
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```java
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import com.lancedb.LanceDbNamespaceClientBuilder;
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import org.lance.namespace.LanceNamespace;
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// If your DB url is db://example-db, then your database here is example-db
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LanceNamespace namespaceClient = LanceDbNamespaceClientBuilder.newBuilder()
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.apiKey("your_lancedb_cloud_api_key")
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.database("your_database_name")
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.build();
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```
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### LanceDB Enterprise
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For Enterprise deployments, use your custom endpoint:
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```java
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LanceNamespace namespaceClient = LanceDbNamespaceClientBuilder.newBuilder()
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.apiKey("your_lancedb_enterprise_api_key")
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.database("your_database_name")
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.endpoint("<your_enterprise_endpoint>")
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.build();
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```
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## MemWAL write path
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Most table operations reach LanceDB through the `LanceNamespace` above, which is
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generated from the Lance Namespace specification. The MemWAL LSM routes are not part
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of that specification, so they are issued through a separate client:
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```java
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import com.lancedb.LanceDbRestClient;
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import com.lancedb.LanceDbTableMemWal;
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import com.lancedb.MemWalWriteSpec;
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LanceDbRestClient client = LanceDbNamespaceClientBuilder.newBuilder()
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.apiKey("your_lancedb_cloud_api_key")
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.database("your_database_name")
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.buildRestClient();
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LanceDbTableMemWal memWal = new LanceDbTableMemWal(client, "my_table");
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// Route future merge_insert upserts through the MemWAL, hash-bucketed by `id`.
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memWal.enableMemWal(MemWalWriteSpec.bucket("id", 16));
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// ... merge_insert traffic ...
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// Converge the fresh tier into the base table.
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memWal.checkpointMemWal();
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// Inspect live per-table-shard state.
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memWal.getMemWalStats().ifPresent(stats -> stats.tableShards().forEach(tableShard ->
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System.out.println(tableShard.shardId() + ": " + tableShard.sstables().size() + " SSTables")));
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client.close();
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```
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`maintainedIndexes` is tri-state, and the null default is the opposite of what a Java
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reader usually expects:
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| Value | Meaning |
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| --- | --- |
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| unset (null) | Maintain **every** index the table has, including ones created later |
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| `Collections.emptyList()` | Maintain **none** |
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| `Arrays.asList("id_idx")` | Maintain exactly those |
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## Development
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The parent POM includes `https://maven.lance.org` to resolve Lance beta and RC
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dependencies. Use an explicit `lance-core.version`; numbered beta and RC versions
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are Maven releases, not snapshots. Maven Central remains available for stable
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and historical versions, as well as other dependencies.
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Build:
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```shell
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./mvnw install -pl lancedb-core -am
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```
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Run tests:
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```shell
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./mvnw test -pl lancedb-core
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```
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