Question

I have a table t1 and two indexes:

create index if not exists timeindex on t1(time, "Bytes Received")
create index if not exists filenameindex on t1(filename)

The next query executes fast enough:

select "Bytes Received" from t1 where time>="11:19:31.18" and time <= "11:19:36.18"

But when I add an additional condition to WHERE statement the query slows down tremendously

select "Bytes Received" 
    from t1 
    where time>="11:19:31.18" and time <= "11:19:36.18"
    and filename = "SE12.log"

I’ve tried to create a new index t1(time, "Bytes Received", filename) but execution speed didn’t changed.

How should I change the indexes in the table to speed up the query?

Answer 1

Use BETWEEN and the following index:

CREATE INDEX IF NOT EXISTS fntimeindex ON t1(filename ASC, time ASC);
SELECT "Bytes Received"
  FROM t1 INDEXED BY fntimeindex
  WHERE filename = 'SE12.log'
   AND time BETWEEN '11:19:31.18' AND '11:19:36.18';

Also note that in SQL strings are enclosed in simple quotes (double quotes are for table, schemas and column names).