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Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/13022 Currently, `blob_garbage_collection_force_threshold` applies to the oldest batch of blob files, which is typically only a small subset of the blob files currently eligible for garbage collection. This can result in a form of head-of-line blocking: no GC-triggered compactions will be scheduled if the oldest batch does not currently exceed the threshold, even if a lot of higher-numbered blob files do. This can in turn lead to high space amplification that exceeds the soft bound implicit in the force threshold (e.g. 50% would suggest a space amp of <2 and 75% would imply a space amp of <4). The patch changes the semantics of this configuration threshold to apply to the entire set of blob files that are eligible for garbage collection based on `blob_garbage_collection_age_cutoff`. This provides more intuitive semantics for the option and can provide a better write amp/space amp trade-off. (Note that GC-triggered compactions still pick the same SST files as before, so triggered GC still targets the oldest the blob files.) Reviewed By: jowlyzhang Differential Revision: D62977860 fbshipit-source-id: a999f31fe9cdda313de513f0e7a6fc707424d4a3 |
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| add.sh | ||
| README.txt | ||
| release.sh | ||
Adding release notes -------------------- When adding release notes for the next release, add a file to one of these directories: unreleased_history/new_features unreleased_history/behavior_changes unreleased_history/public_api_changes unreleased_history/bug_fixes with a unique name that makes sense for your change, preferably using the .md extension for syntax highlighting. There is a script to help, as in $ unreleased_history/add.sh unreleased_history/bug_fixes/crash_in_feature.md or simply $ unreleased_history/add.sh will take you through some prompts. The file should usually contain one line of markdown, and "* " is not required, as it will automatically be inserted later if not included at the start of the first line in the file. Extra newlines or missing trailing newlines will also be corrected. The only times release notes should be added directly to HISTORY are if * A release is being amended or corrected after it is already "cut" but not tagged, which should be rare. * A single commit contains a noteworthy change and a patch release version bump Ordering of entries ------------------- Within each group, entries will be included using ls sort order, so important entries could start their file name with a small three digit number like 100pretty_important.md. The ordering of groups such as new_features vs. public_api_changes is hard-coded in unreleased_history/release.sh Updating HISTORY.md with release notes -------------------------------------- The script unreleased_history/release.sh does this. Run the script before updating version.h to the next development release, so that the script will pick up the version being released. You might want to start with $ DRY_RUN=1 unreleased_history/release.sh | less to check for problems and preview the output. Then run $ unreleased_history/release.sh which will git rm some files and modify HISTORY.md. You still need to commit the changes, or revert with the command reported in the output. Why not update HISTORY.md directly? ----------------------------------- First, it was common to hit unnecessary merge conflicts when adding entries to HISTORY.md, which slowed development. Second, when a PR was opened before a release cut and landed after the release cut, it was easy to add the HISTORY entry to the wrong version's history. This new setup completely fixes both of those issues, with perhaps slightly more initial work to create each entry. There is also now an extra step in using `git blame` to map a release note to its source code implementation, but that is a relatively rare operation.