# Percolator case study (Continue...)

+ Commit primary:



![left](./student-guide/diagram/11-example-03-02.png)

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Commit Secondaries - Commit Secondaries (asynchronous)
1. There are two main cases of asynchronous commit. One is a normal asynchronous commit. The operation process is to clarify the lock on joe lock and add version number 8 to write and point to data 7.
2. If a failure occurs during the asynchronous commit process, lock data will be left on joe. So what's the impact of this missing data?
3. Actually, it has no effect. If something else reads joe version number 7 data, it will find a lock information. At this time, it will read the lock information corresponding to bob according to the primary corresponding to lock. At this point, it was discovered that Bob no longer had a lock message, and it was triggered to clarify the lock information in JOE.