rocksdb/unreleased_history
akankshamahajan ed5b6c0d99 Avoid alignment in FilePrefetchBuffer during seek with async_io (#11793)
Summary:
During Seek, the iterator seeks every file on L0. In async_io, it submit the requests to seek on every file on L0 asynchronously using RocksDB FilePrefetchBuffer.
However, FilePrefetchBuffer does alignment and reads extra bytes then needed that can increase the throughput.
In case of non direct io, the alignment can be avoided.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11793

Test Plan:
- Added a unit test that fails without this PR.
- make crash_test -j32 completed successfully

Reviewed By: anand1976

Differential Revision: D48985051

Pulled By: akankshamahajan15

fbshipit-source-id: 2d130a9e7c3df9c4fcd0408406e6277ab75a4389
2023-09-11 11:41:44 -07:00
..
behavior_changes Minor refactor on LDB command for wide column support and release note (#11777) 2023-08-31 16:17:03 -07:00
bug_fixes Avoid alignment in FilePrefetchBuffer during seek with async_io (#11793) 2023-09-11 11:41:44 -07:00
new_features Minor refactor on LDB command for wide column support and release note (#11777) 2023-08-31 16:17:03 -07:00
performance_improvements Update for 8.5.fb branch cut (#11642) 2023-08-02 12:34:11 -07:00
public_api_changes Change compaction_readahead_size default value to 2MB (#11762) 2023-08-30 14:57:08 -07:00
README.txt Better management of unreleased HISTORY (#11481) 2023-05-30 16:42:49 -07:00
add.sh Some fixes to unreleased_history/ (#11504) 2023-06-02 15:55:02 -07:00
release.sh Update for 8.5.fb branch cut (#11642) 2023-08-02 12:34:11 -07:00

README.txt

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 develpment 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 slighly 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.