rocksdb/unreleased_history
Yu Zhang 2cb00c6921 Ingest files in separate batches if they overlap (#13064)
Summary:
This PR assigns levels to files in separate batches if they overlap. This approach can potentially assign external files to lower levels.

In the prepare stage, if the input files' key range overlaps themselves, we divide them up in the user specified order into multiple batches. Where the files in the same batch do not overlap with each other, but key range could overlap between batches. If the input files' key range don't overlap, they always just make one default batch.

During the level assignment stage, we assign levels to files one batch after another.  It's guaranteed that files within one batch are not overlapping, we assign level to each file one after another. If the previous batch's uppermost level is specified, all files in this batch will be assigned to levels that are higher than that level. The uppermost level used by this batch of files is also tracked, so that it can be used by the next batch.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13064

Test Plan:
Updated test and added new test
Manually stress tested

Reviewed By: cbi42

Differential Revision: D64428373

Pulled By: jowlyzhang

fbshipit-source-id: 5aeff125c14094c87cc50088505010dfd2da3d6e
2024-10-15 17:22:01 -07:00
..
behavior_changes Ingest files in separate batches if they overlap (#13064) 2024-10-15 17:22:01 -07:00
bug_fixes
new_features Make simple BlockBasedTableOptions mutable (#10021) 2024-10-14 17:49:26 -07:00
performance_improvements
public_api_changes
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.