为什么我们不看一下磁盘上具有静态列的表的结构并找出答案呢?
cqlsh:test> CREATE TABLE test (k int, v int, s int static, d int, PRIMARY KEY(k,v))
cqlsh:test> INSERT INTO test (k, v, s, d) VALUES ( 1, 1 ,20, 1 );
cqlsh:test> INSERT INTO test (k, v, s, d) VALUES ( 1, 3 ,21, 2 );
cqlsh:test> INSERT INTO test (k, v, s, d) VALUES ( 1, 2 ,21, 2 );
退出 C* 并运行nodetool flush
来制作我们的马厩。跑步sstable2json
在数据目录中创建的 .db 文件上。
[
{"key": "1", <--- K=1 Partition
"cells": [[":s","21",1425050917842350], <---- Our Static Column
["1:","",1425050906896717], < --- C=1 row
["1:d","1",1425050906896717], < --- C=1, D=1 value
["2:","",1425050917842350], < --- C=2 row
["2:d","2",1425050917842350], < --- C=2, D=2 value
["3:","",1425050912874025], <--- C=3 Row
["3:d","2",1425050912874025]]} <--- C=3, D=2 Value
]
您可以看到,在 Cassandra 中,此静态列保存在分区开头的标题为“Blank:ColumnName”的单元格中。与所有其他细胞不同的是,没有关于c(我们的聚类列)在单元格名称中,因此所有值c仍会修改相同的静态列s
有关原因的更多详细信息,请查看 JIRA:https://issues.apache.org/jira/browse/CASSANDRA-6561 https://issues.apache.org/jira/browse/CASSANDRA-6561以及博客文章http://www.datastax.com/dev/blog/cql-in-2-0-6 http://www.datastax.com/dev/blog/cql-in-2-0-6