---
warning: DO NOT CHANGE THIS MANUALLY, THIS IS GENERATED BY https://github.com/duckdb/community-extensions repository, check README there
title: query_limiter
excerpt: |
  DuckDB Community Extensions
  Reject queries before physical execution when estimated table scans exceed a configured row budget

extension:
  name: query_limiter
  description: Reject queries before physical execution when estimated table scans exceed a configured row budget
  version: 0.2.0
  language: C++
  build: cmake
  license: MIT
  excluded_platforms: "wasm_mvp;wasm_eh;wasm_threads"
  maintainers:
    - dentiny

repo:
  github: dentiny/duckdb-query-limiter
  variegata: 8febc919c9240343112b6a54468074fe48628ea1
  ref: 739c7964074f2adce00cdf9dc130a109d0b01e6f

docs:
  hello_world: |
    SET max_rows_to_scan = 1000000;
    CREATE TABLE limiter_demo AS SELECT i FROM range(100) tbl(i);
    SELECT sum(i) FROM limiter_demo;
  extended_description: |
    Query Limiter is a DuckDB extension that rejects queries before physical execution when DuckDB estimates that table scans would exceed a configured row budget.

extension_star_count: 1
extension_star_count_pretty: 1
extension_download_count: 842
extension_download_count_pretty: 842
image: '/images/community_extensions/social_preview/preview_community_extension_query_limiter.png'
layout: community_extension_doc
---
### Compatibility Matrix

This table covers all DuckDB releases that have not reached [end-of-life](https://duckdb.org/release_calendar), including LTS releases, and shows the 2 most recent patch releases of each. Older patch releases are not listed, but the extension may be available for them as well.

<div class="extension_compatibility_table"></div>

| Platform | 1.4.4 | 1.4.5 | 1.5.5 | 1.5.6 | 2.0.0 |
| :--- | :---: | :---: | :---: | :---: | :---: |
| Linux AMD64 | ❌ | ❌ | ✅ | ✅ | ✅ |
| Linux ARM64 | ❌ | ❌ | ✅ | ✅ | ✅ |
| macOS AMD64 | ❌ | ❌ | ✅ | ✅ | ✅ |
| macOS ARM64 | ❌ | ❌ | ✅ | ✅ | ✅ |
| Windows AMD64 | ❌ | ❌ | ✅ | ✅ | ✅ |
| Windows ARM64 | ❌ | ❌ | ❌ | ❌ | ❌ |
| WebAssembly | ❌ | ❌ | ❌ | ❌ | ❌ |

### Installing and Loading
```sql
INSTALL {{ page.extension.name }} FROM community;
LOAD {{ page.extension.name }};
```

{% if page.docs.hello_world %}
### Example
```sql
{{ page.docs.hello_world }}```
{% endif %}

{% if page.docs.extended_description %}
### About {{ page.extension.name }}
{{ page.docs.extended_description }}
{% endif %}
### Added Functions

<div class="extension_functions_table"></div>

|     function_name      | function_type |                                                description                                                | comment |                          examples                          |
|------------------------|---------------|-----------------------------------------------------------------------------------------------------------|---------|------------------------------------------------------------|
| query_limiter_estimate | scalar        | Plans one SQL statement without executing it and returns its estimated table-scan rows and unknown scans. | NULL    | [SELECT query_limiter_estimate('SELECT * FROM my_table');] |

### Overloaded Functions

<div class="extension_functions_table"></div>

This extension does not add any function overloads.

### Added Types

<div class="extension_types_table"></div>

This extension does not add any types.

### Added Settings

<div class="extension_settings_table"></div>

|           name           |                                                      description                                                       | input_type | scope  | aliases |     typed_value      |
|--------------------------|------------------------------------------------------------------------------------------------------------------------|------------|--------|---------|----------------------|
| max_rows_to_scan         | Reject queries before execution when estimated table-scan rows exceed this value. Defaults to the maximum idx_t value. | UBIGINT    | GLOBAL | []      | 18446744073709551615 |
| max_rows_to_scan_unknown | Policy for scans without row estimates when max_rows_to_scan is enabled: allow or reject.                              | VARCHAR    | GLOBAL | []      | allow                |
| temp_directory           | Set the directory to which temporary files are written.                                                                | VARCHAR    | GLOBAL | []      | post.db.tmp          |