thanks James!
Hint the query to force use index works.
but can this be more automatic?
I mean obviously with case like problem1, using index NAME will be better ?
在 2016年05月10日 14:56, James Taylor 写道:
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 <[email protected]
<mailto:[email protected]>> 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) |
+-------------------------------------------------------------+
