March 2021
Intermediate to advanced
265 pages
6h 50m
Chinese
Content preview from Presto实战
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
Start your free trial
高级连接器实例
｜
103
个范围放入分片中，由工作节点进行处理，这样就可以直接访问各个值，数据详细视图如
表
7-4
中所示。
表7-4：出发地、目的地及其他值的详细视图
Rowid Column Value
2232 flightdate:flightdate 2019-10-19
2232 flightnum:flightnum 118
2232 origin:origin JFK
2232 dest:dest SFO
1234 flightdate:flightdate 2019-11-02
1234 flightnum:flightnum 2237
1234 origin:origin BOS
1234 dest:dest DTW
5678 flightdate:flightdate 2019-11-02
5678 flightnum:flightnum 133
5678 origin:origin BOS
5678 dest:dest SFO
3498 flightdate:flightdate 2019-11-10
3498 flightnum:flightnum 133
3498 origin:origin BOS
3498 dest:dest SFO
为了利用谓词下推的优势，需要在想要下推谓词的列上建立索引。通过
Presto
连接器，可
以使用
index_columns
表属性在列上建立索引。
CREATE TABLE accumulo.ontime.flights (
rowid VARCHAR,
flightdate VARCHAR, ...