---
warning: DO NOT CHANGE THIS MANUALLY, THIS IS GENERATED BY https://github.com/duckdb/community-extensions repository, check README there
title: lakemon
excerpt: |
  DuckDB Community Extensions
  Smart DuckLake table maintain (adaptive rewrite + merge) and catalog-global expire/cleanup

# Copy this file to duckdb/community-extensions as
#   extensions/lakemon/description.yml
# and set repo.ref to a commit SHA of paulosuzart/lakemon-duckdb-ext.
# Official docs: https://duckdb.org/community_extensions/documentation
#
# The repository must be public before the community CI can clone it.

extension:
  name: lakemon
  description: Smart DuckLake table maintain (adaptive rewrite + merge) and catalog-global expire/cleanup
  version: 0.2.0
  language: C++
  build: cmake
  license: MIT
  maintainers:
    - paulosuzart

repo:
  github: paulosuzart/lakemon-duckdb-ext
  # Built against latest stable DuckDB (v2.0.0); v1.5.6 rebuilds use the same ref.
  ref: 31e6fe098ecff4f0d29f2044d47f86fd6c4f5829

docs:
  hello_world: |
    INSTALL ducklake;
    LOAD ducklake;
    INSTALL lakemon FROM community;
    LOAD lakemon;

    ATTACH 'ducklake:metadata.ducklake' AS lake (DATA_PATH 'data_files');

    CALL lakemon_table_stats('lake');
    CALL lakemon_maintain('lake');
    CALL lakemon_maintain_global('lake');
    CALL lakemon_maintain('lake', dry_run => true);
    CALL lakemon_policy();

  extended_description: |
    lakemon orchestrates native DuckLake maintenance CALLs with a policy layer:

    * Catalog SELECT inventory of data files, delete files, and inlined-delete backlog
    * Flush guard (lakemon_flush_inlined_max_delete_files) so a large ended-file delete backlog cannot block rewrite/merge
    * Byte-weighted adaptive rewrite ladder (delete fraction DESC; one ducklake_rewrite_data_files CALL per byte-cut rung)
    * Merge size bands (micro / small / medium) with per-tier target_file_size
    * Table maintain (lakemon_maintain) vs catalog-global expire/cleanup (lakemon_maintain_global)
    * CALL / SELECT plan and execute by default (dry_run for plan only)
    * One result row per step (ok / skip / error / planned)
    * Optional stderr step logs with duration and byte-weighted progress

    Requires the core ducklake extension in the same session and an attached DuckLake catalog.
    Compatible with DuckDB 1.5.6 and DuckDB 2.0.0 (lakemon 0.2.0+). Older DuckDB 1.5.x builds are no longer produced.

extension_star_count: 1
extension_star_count_pretty: 1
extension_download_count: 722
extension_download_count_pretty: 722
image: '/images/community_extensions/social_preview/preview_community_extension_lakemon.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 |
|-------------------------|---------------|-------------|---------|----------|
| lakemon_maintain        | pragma        | NULL        | NULL    |          |
| lakemon_maintain        | table         | NULL        | NULL    |          |
| lakemon_maintain_global | pragma        | NULL        | NULL    |          |
| lakemon_maintain_global | table         | NULL        | NULL    |          |
| lakemon_policy          | table         | NULL        | NULL    |          |
| lakemon_set_policy      | table         | NULL        | NULL    |          |
| lakemon_table_stats     | table         | NULL        | NULL    |          |
| lakemon_version         | scalar        | NULL        | NULL    |          |

### 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 |
|----------------------------------------|--------------------------------------------------------------------------------------------------------------------------|------------|--------|---------|-------------|
| lakemon_flush_inlined_max_delete_files | Skip ducklake_flush_inlined_data when the planned delete-file count exceeds this (0 = no limit). Negatives are rejected. | BIGINT     | GLOBAL | []      | 500         |
| lakemon_log_stderr                     | Write lakemon maintain step start/end lines to stderr                                                                    | BOOLEAN    | GLOBAL | []      | false       |
| temp_directory                         | Set the directory to which temporary files are written.                                                                  | VARCHAR    | GLOBAL | []      | post.db.tmp |