optimize: improve UUIDGenerator using "history time" version of snowflake algorithm #3175
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
added 2 commits
October 10, 2020 11:27
Codecov Report
@@ Coverage Diff @@
## develop #3175 +/- ##
=============================================
+ Coverage 51.11% 51.12% +0.01%
- Complexity 3297 3300 +3
=============================================
Files 614 614
Lines 20125 20149 +24
Branches 2514 2519 +5
=============================================
+ Hits 10287 10302 +15
- Misses 8806 8815 +9
Partials 1032 1032
|
funky-eyes
added
first-time contributor
funky-eyes
reviewed
Oct 12, 2020
l81893521
reviewed
Dec 5, 2020
| timestamp = timeGen(); | ||
| private void waitIfNecessary() { | ||
| long currentWithSequence = timestampAndSequence.get(); | ||
| long current = currentWithSequence >>> sequenceBits; |
There was a problem hiding this comment.
if currentWithSequence will never be negative number, I think use
>>
is enought.
There was a problem hiding this comment.
currentWithSequence could be a negative number(though it would be a long long time to reach this~). What ever, >>> and >> have the same speed for cpu.
l81893521
reviewed
Dec 8, 2020
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Ⅰ. Describe what this PR did
Improve UUIDGenerator base on an improved snowflake algorithm which use "history time" instead of current timestamp.
algorithm doc
So that seata-server can support system time move backward during run time.
Beside, implement is base on CAS instead of Lock, so it would be faster~
Ⅱ. Does this pull request fix one issue?
fixes #3126
Ⅳ. Describe how to verify it
run seata-server in a server, then change machine's system time to a previous time, if seata-server can still generate normal UUID, then it proved worked.