mirror of
https://github.com/lancedb/lancedb.git
synced 2026-10-14 15:52:26 +00:00
Brendan Clement
622e6078c1
Main now rebuilds a materialized view completely on every refresh (#4373): there is no incremental mode, no `full` argument and no stable-row-ID requirement on the source. The example ran against the SDK built from this branch (0.40.0b13) failed, because a refresh after adding Bea writes both matching rows, not one. The example now creates its source with the default options and expects two rows written by the refresh, and its generated snippet is regenerated. Separate tests cover `with_no_data` (one matching row on the first refresh) and refreshing to an earlier source version. The refresh page explains the full rebuild and keeps the #incremental and #stable-row-ids anchors for the sections that replace them. Its version note now says what the published 0.39.0 does differently, as observed with that release. The management, table, database, limits, architecture and data-types pages no longer say a view's source needs stable row ids, and the feature-engineering and tutorial summaries no longer call refreshes incremental.
102 lines
3.5 KiB
Plaintext
102 lines
3.5 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.
|
|
|
|
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 |
|
|
|
|
Stable row ids **cannot be enabled after a table exists** -- the one schema
|
|
decision here that is genuinely irreversible.
|
|
|
|
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` | parsed, not yet implemented |
|
|
|
|
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.
|