mirror of
https://github.com/lancedb/lancedb.git
synced 2026-10-13 15:22:30 +00:00
Brendan Clement
6a1645116e
Creating, writing, updating, merging and deleting rows, managing tables, branches and read consistency work in the embedded library and on a deployment, and those pages now say so. The SQL forms they mention need a deployment. Where the offerings differ, the section says how: a deployment reuses an existing table without comparing schemas, a merge insert can be refused past a configured number of unindexed rows, space is reclaimed by optimize() locally and by the deployment's compaction and configured cleanup otherwise, renaming depends on the catalog, a deployment clones shallowly only, drops all tables only locally, keeps freshness state per table handle and defaults freshness to its own setting, and refuses to delete a branch main depends on. table_exists works only on a namespace connection. Guarantees and limits span both offerings, so they carry section notes rather than a label: reads, retention, index freshness and compaction differ on a deployment, and the name and job limits are a deployment's.
113 lines
4.3 KiB
Plaintext
113 lines
4.3 KiB
Plaintext
---
|
|
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.
|
|
|
|
Some of these bounds apply only on a deployment, as their sections say. Quotas
|
|
that a deployment sets -- 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. These lengths are a deployment's
|
|
limits; the embedded library does not limit name length.
|
|
|
|
## Jobs {#jobs}
|
|
|
|
<Badge color="red">Enterprise</Badge> These bounds belong to a deployment's job
|
|
service. Jobs on a local database run in-process and keep no event history.
|
|
|
|
| | |
|
|
| --- | --- |
|
|
| `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 on a deployment | needs its Flight SQL endpoint enabled and reachable |
|
|
| 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 | [depends on the deployment](/basics/sql#no-vector-sql); the query builder always has it |
|
|
| 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 three 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.
|