lancedb/docs/web/basics/lakehouse.mdx

---
title: "Lance Lakehouse"
sidebarTitle: "Lance Lakehouse"
description: "What operates on the catalog's objects: storage, search, computation, and maintenance."
icon: layer-group
keywords: ["lakehouse", "multimodal", "search", "compute", "maintenance", "feature engineering"]
---

The [catalog](/basics/catalog) says what exists. The **lakehouse** is everything
that acts on it: storing the rows, searching them, computing new ones, and
keeping the whole thing fast as it grows.

The distinction matters because the two layers have different lifetimes. A
catalog entry is a name and a pointer. A lakehouse operation reads and writes
the [Lance](/basics/lance) files that name points at -- and those operations are
where almost all of the cost, and all of the tuning, lives.

## Multimodal is the point {#multimodal}

A lakehouse table holds images, video, audio, text, embeddings, annotations and
the features you derive from them **in one table**, side by side.

That is the difference from assembling a warehouse plus a vector store plus a
feature store. There is one copy of the data, one set of versions, and no
pipeline keeping three systems agreeing about the same rows. A search can filter
on a label, rank by a vector, and return the blob, without leaving the table.

| | |
| --- | --- |
| **Columns** | vectors, blobs, and columns [computed](/feature-engineering/add-computed-column) from other columns |
| **Versions** | every write commits one, so reads can [travel back](/management/table#versioning) |
| **Indexes** | vector, full-text and scalar, built over those columns |
| **Branches** | isolated lines of change you can [merge or discard](/tables/branching) |

## The four capabilities {#capabilities}

Everything the lakehouse does falls into one of four groups, and the rest of
these docs is organized the same way.

### Ingest {#ingest}

Getting rows in, and changing the ones that are there: append, merge, update,
delete. Every write commits a version rather than mutating in place, which is
what makes the other three safe to run against a moving table. See
[Data Ingestion](/ingestion).

### Search {#search}

Vector, full-text and hybrid retrieval over the same rows, with filters that
push into the scan rather than running after it. The search is a lakehouse
operation, not a separate service holding a second copy of your embeddings. See
[Semantic Search](/search).

### Compute {#compute}

Deriving new columns and tables from what is already stored:
[computed columns](/feature-engineering/add-computed-column),
[functions](/management/function) that run Python where the data is, and
[materialized views](/management/materialized-view) that persist a query's
result.

The reason this belongs in the lakehouse rather than in a pipeline outside it is
the format. Adding a derived column writes only that column -- the images and
videos are never rewritten -- so deriving a feature is an ordinary operation
rather than a migration. See [Feature Engineering](/feature-engineering) and
[Data Curation](/curation).

### Maintenance {#maintenance}

The work that keeps the first three fast: building and repairing
[indexes](/indexing), and [compaction](/maintenance/compaction) to merge small
files, prune old versions and fold new rows into existing indexes.

<Warning>
None of it runs on its own. There is no background compactor -- `optimize()`
runs when you call it, and an index does not cover rows added after it was
built until you do. See [Guarantees](/basics/guarantees#not-guaranteed).
</Warning>

## Where the work happens {#where}

The same lakehouse runs in two shapes, and which one you use decides where these
capabilities execute rather than whether you have them:

- **Embedded** -- your process does all four itself, directly against object
  storage. Nothing runs unless you call it.
- **Distributed** -- a cluster does them, with indexing and compaction on
  workers separate from the ones serving queries, plus
  [SQL](/sql) and server-side [jobs](/basics/jobs).

See [Architecture](/architecture) for the comparison in full.

## Next {#next}

<CardGroup cols={2}>
  <Card title="Lance Catalog" icon="sitemap" href="/basics/catalog">
    The objects these operations act on.
  </Card>
  <Card title="Lance format" icon="layer-group" href="/basics/lance">
    The open format underneath, and why column evolution is cheap.
  </Card>
</CardGroup>