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Copilot AI commented Dec 16, 2025

What's Changed in this PR

Documents new cache configuration options introduced in GreptimeTeam/greptimedb#7294, which controls whether files are downloaded from object storage to fill the local cache on write cache miss.

Also removes outdated read cache documentation from the Object storage cache section, as read cache has been removed from GreptimeDB.

Configuration changes documented:

  • Added cache_file_on_write_miss (Boolean, default: true) to mito region engine options
  • Added manifest_cache_size (String, default: 256MB) to mito region engine options - cache size for manifest file cache
  • Added previously missing write_cache_size to the configuration options table
  • Updated object storage cache section with behavior explanation and usage guidance
  • Removed outdated read cache documentation (cache_path, cache_capacity configs)

Example configuration:

[[region_engine]]
[region_engine.mito]
write_cache_size = "10GiB"
cache_file_on_write_miss = true  # Download files from object storage on cache miss
manifest_cache_size = "256MB"    # Cache size for manifest file cache

When cache_file_on_write_miss is enabled (default), improves query performance by automatically populating the local cache from object storage. Disable to reduce network traffic at the cost of query performance.

Files updated:

  • Current version (English): configuration.md, performance-tuning-tips.md
  • Current version (Chinese): corresponding zh translations
  • Version 1.0 (English): configuration.md, performance-tuning-tips.md
  • Version 1.0 (Chinese): corresponding zh translations

Checklist

  • Please confirm that all corresponding versions of the documents have been revised.
  • Please ensure that the content in sidebars.ts matches the current document structure when you changed the document structure.
  • This change requires follow-up update in localized docs.
Original prompt

This section details on the original issue you should resolve

<issue_title>Update docs for feat!: download file to fill the cache on write cache miss</issue_title>
<issue_description>A document change request is generated from GreptimeTeam/greptimedb#7294</issue_description>

Comments on the Issue (you are @copilot in this section)


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Copilot AI changed the title [WIP] Update documentation for file download feature docs: add cache_file_on_write_miss configuration for write cache behavior Dec 16, 2025
Copilot AI requested a review from fengjiachun December 16, 2025 10:20
@fengjiachun fengjiachun requested review from evenyag and removed request for fengjiachun December 16, 2025 10:50
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@evenyag PTAL

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@copilot Also need to add the documentation for the latest stable release.

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Copilot AI commented Dec 18, 2025

@copilot Also need to add the documentation for the latest stable release.

Added documentation for version 1.0 (latest stable release) in commit d3232c6. Updated both English and Chinese versions of configuration.md and performance-tuning-tips.md for version 1.0.

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evenyag commented Dec 18, 2025

@copilot Remove outdated document in deployments-administration/configuration/#object-storage-cache about the read cache. e.g. The Object storage cache section. Read cache has been removed, configs like cache_path are outdated. We should document the configuration of write cache instead.

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Copilot AI commented Dec 18, 2025

@copilot Remove outdated document in deployments-administration/configuration/#object-storage-cache about the read cache. e.g. The Object storage cache section. Read cache has been removed, configs ...

Removed outdated read cache documentation from the Object storage cache section in commit 145a7fa. Deleted references to cache_path and cache_capacity configs, and updated the section to focus on write cache configuration instead. Changes applied to both current and version 1.0 documentation (English and Chinese).

Copilot AI changed the title docs: add cache_file_on_write_miss configuration for write cache behavior docs: add cache_file_on_write_miss configuration and remove outdated read cache docs Dec 18, 2025
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evenyag commented Dec 18, 2025

@copilot Also add the docs for the manifest_cache_size.

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Copilot AI commented Dec 18, 2025

@copilot Also add the docs for the manifest_cache_size.

Added documentation for manifest_cache_size configuration option in commit 4f15c27. Updated both the frequently used options example and the options table for current and version 1.0 documentation (English and Chinese).

Copilot AI changed the title docs: add cache_file_on_write_miss configuration and remove outdated read cache docs docs: add cache configuration options and remove outdated read cache docs Dec 18, 2025
Copilot AI requested a review from evenyag December 18, 2025 12:15
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evenyag commented Dec 19, 2025

@copilot The manifest_cache_size is the capacity for manifest file cache (default: 256MB).

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Copilot AI commented Dec 19, 2025

@copilot The manifest_cache_size is the capacity for manifest file cache (default: 256MB).

Updated manifest_cache_size default value to 256MB and clarified the description as "manifest file cache" in commit ed34cc1. Changes applied to both current and version 1.0 documentation (English and Chinese).

@evenyag evenyag marked this pull request as ready for review December 19, 2025 13:17
@evenyag evenyag requested a review from killme2008 as a code owner December 19, 2025 13:17
@killme2008 killme2008 merged commit bf8bc4d into main Dec 30, 2025
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@killme2008 killme2008 deleted the copilot/update-docs-fill-cache branch December 30, 2025 06:26
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Update docs for feat!: download file to fill the cache on write cache miss

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