GAE @Persistent（valueStrategy = IdGeneratorStrategy.SEQUENCE）不生成序号

Question

我有一个领域：

当我把它放入：

它不会按顺序生成

序列号不正常的原因是什么？我会在两个单独的帖子中添加日志，因为它们对于这篇帖子来说太大了。

1:1422624487.413000 [s~server-test-killesk/12.381882801386260762].<stdout>: 13:28:07,413 DEBUG Request FC14E205 ValueGeneration:debug:58 - Creating ValueGenerator instance of "com.google.appengine.datanucleus.valuegenerator.SequenceGenerator" for "com.eurekaapp.server.dao.mappedobjects.DAOJobEvent.sequence"
1:1422624487.424000 [s~server-test-killesk/12.381882801386260762].<stdout>: 13:28:07,423 DEBUG Request FC14E205 ValueGeneration:debug:58 - Generated value for field "com.eurekaapp.server.dao.mappedobjects.DAOJobEvent.sequence" using strategy="sequence" (Generator="com.google.appengine.datanucleus.valuegenerator.SequenceGenerator") : value=1,050,002
1:1422624487.624000 [s~server-test-killesk/12.381882801386260762].<stdout>: 13:28:07,624 DEBUG Request FC14E205 ValueGeneration:debug:58 - Generated value for field "com.eurekaapp.server.dao.mappedobjects.DAOJobEvent.sequence" using strategy="sequence" (Generator="com.google.appengine.datanucleus.valuegenerator.SequenceGenerator") : value=1,040,003
1:1422624487.908000 [s~server-test-killesk/12.381882801386260762].<stdout>: 13:28:07,907 DEBUG Request FC14E205 ValueGeneration:debug:58 - Generated value for field "com.eurekaapp.server.dao.mappedobjects.DAOJobEvent.sequence" using strategy="sequence" (Generator="com.google.appengine.datanucleus.valuegenerator.SequenceGenerator") : value=3,010,003

Answer 1

IdGeneratorStrategy.SEQUENCE是在DatastoreService.allocateIds()之上实现的，这是Cloud Datastore内部分配ID的方式。适用于Cloud Datastore auto-Id分配的所有内容都适用于SEQUENCE。

序列只能保证唯一，而不是单调增加。