rocksdb/unreleased_history
Changyu Bi 5c2a063c49 Clarify usage for options ttl and periodic_compaction_seconds for universal compaction (#11552)
Summary:
this is stacked on https://github.com/facebook/rocksdb/issues/11550 to further clarify usage of these two options for universal compaction. Similar to FIFO, the two options have the same meaning for universal compaction, which can be confusing to use. For example, for universal compaction, dynamically changing the value of `ttl` has no impact on periodic compactions. Users should dynamically change `periodic_compaction_seconds` instead. From feature matrix (https://fburl.com/daiquery/5s647hwh), there are instances where users set `ttl` to non-zero value and `periodic_compaction_seconds` to 0. For backward compatibility reason, instead of deprecating `ttl`, comments are added to mention that `periodic_compaction_seconds` are preferred. In `SanitizeOptions()`, we update the value of `periodic_compaction_seconds` to take into account value of `ttl`. The logic is documented in relevant option comment.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11552

Test Plan: * updated existing unit test `DBTestUniversalCompaction2.PeriodicCompactionDefault`

Reviewed By: ajkr

Differential Revision: D47381434

Pulled By: cbi42

fbshipit-source-id: bc41f29f77318bae9a96be84dd89bf5617c7fd57
2023-07-26 11:31:54 -07:00
..
behavior_changes Clarify usage for options ttl and periodic_compaction_seconds for universal compaction (#11552) 2023-07-26 11:31:54 -07:00
bug_fixes Update HISTORY.md for branch cut for 8.4.fb (#11565) 2023-06-26 13:26:15 -07:00
new_features Update HISTORY.md for branch cut for 8.4.fb (#11565) 2023-06-26 13:26:15 -07:00
performance_improvements Remove reallocation of AlignedBuffer in direct_io sync reads if already aligned (#11600) 2023-07-14 20:08:05 -07:00
public_api_changes Prepare for specialized interface for row cache (#11620) 2023-07-18 19:12:58 -07:00
add.sh Some fixes to unreleased_history/ (#11504) 2023-06-02 15:55:02 -07:00
README.txt Better management of unreleased HISTORY (#11481) 2023-05-30 16:42:49 -07:00
release.sh Some fixes to unreleased_history/ (#11504) 2023-06-02 15:55:02 -07:00

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.