Cassandra快照中manifest.json的目的是什么

Question

当创建快照时，会创建manifest.json，这个文件的用途是什么？我本以为它包含快照中所有文件的列表，它们是：

2014-11-11 17:36:51         43 keyspace-cf-ka-1-CompressionInfo.db
2014-11-11 17:36:51         87 keyspace-cf-ka-1-Data.db
2014-11-11 17:36:51         10 keyspace-cf-ka-1-Digest.sha1
2014-11-11 17:36:51         16 keyspace-cf-ka-1-Filter.db
2014-11-11 17:36:51         25 keyspace-cf-ka-1-Index.db
2014-11-11 17:36:51       4460 keyspace-cf-ka-1-Statistics.db
2014-11-11 17:36:51        101 keyspace-cf-ka-1-Summary.db
2014-11-11 17:36:51         91 keyspace-cf-ka-1-TOC.txt
2014-11-11 17:36:51         43 keyspace-cf.field2_field1_idx-ka-1-CompressionInfo.db
2014-11-11 17:36:51         63 keyspace-cf.field2_field1_idx-ka-1-Data.db
2014-11-11 17:36:51          9 keyspace-cf.field2_field1_idx-ka-1-Digest.sha1
2014-11-11 17:36:51         16 keyspace-cf.field2_field1_idx-ka-1-Filter.db
2014-11-11 17:36:51         25 keyspace-cf.field2_field1_idx-ka-1-Index.db
2014-11-11 17:36:51       4458 keyspace-cf.field2_field1_idx-ka-1-Statistics.db
2014-11-11 17:36:51        101 keyspace-cf.field2_field1_idx-ka-1-Summary.db
2014-11-11 17:36:51         91 keyspace-cf.field2_field1_idx-ka-1-TOC.txt
2014-11-11 17:36:51         62 manifest.json

但它包含：

{
    "files": [
        "keyspace-cf.field2_field1_idx-ka-1-Data.db"
    ]
}

Answer 1

I包含快照中包含的所有sstables。

https://issues.apache.org/jira/browse/CASSANDRA-6326