Please read the following and hopefully it will answer your questions: https://phoenix.apache.org/secondary_indexing.html#Index_Usage

On Mon, May 9, 2016 at 11:36 PM, 金砖 <jinzhuan@wacai.com> wrote:
hi, I'm using phoenix-4.7,  and I found phoenix did not use index efficiently enough.
Can phoenix optimize more for this situation?

EX:

table:

    create table t (pk varchar primary key, name varchar, age unsigned_int);

and create 2 index on it:
     create index name on t (name);
     create index age on t (age);


problem1:  select * from table did not use index, instead  did full scan on table.


0: jdbc:phoenix:localhost> explain select * from t where name = 'name';
+-------------------------------------------------------------+
|                            PLAN                             |
+-------------------------------------------------------------+
| CLIENT 1-CHUNK PARALLEL 1-WAY ROUND ROBIN FULL SCAN OVER T  |
|     SERVER FILTER BY NAME = 'name'                          |
+-------------------------------------------------------------+


problem2:  when selecting more than 1 field,  neither index will be used.

0: jdbc:phoenix:localhost> explain select name from t where name = 'name' and age > 1;
+-------------------------------------------------------------+
|                            PLAN                             |
+-------------------------------------------------------------+
| CLIENT 1-CHUNK PARALLEL 1-WAY ROUND ROBIN FULL SCAN OVER T  |
|     SERVER FILTER BY (NAME = 'name' AND AGE > 1)            |
+-------------------------------------------------------------+


0: jdbc:phoenix:localhost> explain select age from t where name = 'name' and age > 1;
+-------------------------------------------------------------+
|                            PLAN                             |
+-------------------------------------------------------------+
| CLIENT 1-CHUNK PARALLEL 1-WAY ROUND ROBIN FULL SCAN OVER T  |
|     SERVER FILTER BY (NAME = 'name' AND AGE > 1)            |
+-------------------------------------------------------------+