lancedb/docs/web/basics/limits.mdx

---
title: "Limits"
sidebarTitle: "Limits"
description: "The bounds you can actually hit, in one place."
icon: ruler
keywords: ["limits", "maximum", "quota", "constraints", "bounds"]
---

Limits worth designing around, collected so you do not have to find them by
hitting them. Each one is enforced -- where a value is refused rather than
clamped, that is stated, because the two fail very differently.

This page covers bounds that are the same for everyone. Deployment-specific
quotas -- storage, throughput, concurrency -- come from your deployment.

## Names {#names}

| Object | Maximum | |
| --- | --- | --- |
| Database | 64 characters | |
| Namespace | 64 characters | |
| Table | 128 characters | |
| Branch | 64 characters | |

A name must not be empty, and must not contain `$` or `:` -- both are reserved
as path delimiters, so a name holding one could not be addressed unambiguously.
Length is counted in characters, not bytes.

## Jobs {#jobs}

| | |
| --- | --- |
| `job.events()` default | 1,000 rows |
| `job.events()` maximum | 10,000 rows |
| `SHOW ERRORS ... LIMIT` | between 1 and 100,000 |
| Failed jobs scanned by one `SHOW ERRORS` | 32 |

<Warning>
`job.events()` **truncates silently**. A job that emits an event per fragment
will lose its tail unless you pass `limit` explicitly. This is the limit on this
page most likely to mislead you, because nothing in the result says it was cut.
</Warning>

`SHOW ERRORS` without `FOR JOB` scans the most recent failed jobs and stops at
32 of them. Narrow with `FOR JOB` when you need a specific one rather than a
survey.

See [Jobs](/basics/jobs).

## Schema and types {#schema}

| | |
| --- | --- |
| `map` with `keys_sorted = true` | rejected |
| `IVF_RQ` vector dimensions | must be divisible by 8 |
| FTS `max_token_length` | 40 by default; longer tokens are dropped |

Through the SDK, a table gets **stable row ids** only at creation, from the
`new_table_enable_stable_row_ids` storage option on a local path or an object
store; no SDK call adds them later, so decide early. A local
[materialized view](/feature-engineering/materialized-views#stable-row-ids) does
not need them. On a deployment, whether a view's source needs them and how a
table gets them depend on the deployment; see
[Against a deployment](/feature-engineering/materialized-views#availability).

See [Data types](/sql/data-types).

## SQL {#sql}

<Badge color="red">Enterprise</Badge>

| | |
| --- | --- |
| `TABLESAMPLE` percentage | 0 to 100, **refused** outside -- not clamped |
| `TABLESAMPLE (n ROWS)` | whole numbers only |
| `TABLESAMPLE BUCKET` | not supported |
| `TABLESAMPLE` on a WAL-backed table | not supported |
| `CREATE INDEX` | one column, server-chosen name |
| `REFRESH MATERIALIZED VIEW ... CASCADE` | depends on the deployment's version; see [REFRESH](/sql/dml/refresh#refresh-materialized-view) |

A sampling percentage over 100 is an error rather than a full scan, because a
query asking for 150 percent has a mistake in it and reading it as 100 would
hide the mistake. See [Sampling](/sql/dql/sampling).

## What is unavailable where {#availability}

Not quotas, but the same class of surprise -- things that exist in one place and
not another.

| | |
| --- | --- |
| SQL on a local database | unavailable; `execute_query` raises |
| SQL methods in the TypeScript SDK | none; use a Flight SQL client |
| Function methods in the TypeScript SDK | none; use Python or SQL |
| Vector search in SQL | no SQL form; use a query builder |
| Geospatial `st_*` functions | behind a build feature LanceDB does not ship |
| `tableExists` / `namespaceExists` in TypeScript | not present |
| Server-side jobs on a local database | run in-process; `events()` raises |

See [SQL](/basics/sql) for why the first two hold.

## Nothing here is a quota {#not-quotas}

None of the above is a billing or capacity limit. Rows per table, table count,
storage, and request rate are bounded by your deployment rather than by the
format -- ask your deployment, not this page.