# Percolator case study (Continue...)

+ Commit primary: 


![left](./student-guide/diagram/11-example-03-01.png)

------------------------------------------------------------
Second stage commit — Commit Primary (sync)
1. When all keys have completed the first phase commit, the second phase commit is performed, which is mainly to clear the lock.
2. First it clears the primary key of the lock, and then adds the version number and data point to the write at the same time.
3. In fact, at this stage, the submission is already complete. Submissions for other keys will become asynchronous commits.