slow postgres performance with simple querys

[shizuka]

after alot of reading i found multiple sources saying postgres should be able to handle ~100 million rows

i set up a simple table with:

CREATE TABLE trade
(
    id INT PRIMARY KEY NOT NULL,
    symbol VARCHAR(),
    open_time TIMESTAMP,
    end_price INT
)

i have 12 million of thies records

my simple query of

SELECT * FROM table WHERE symbol=x and open_time>start_time and open_time

this query always returns less than a 1000 rows yet it take 1100 millisecond this seams like alot for a simple table with 10x less rows than it should handle?

altho i dont have any indexes cause i dont know what would be the best indexs to put on this table.

is it possible to get this down to 100ms?

any help writing a more performant query or db would be appriciated

EDIT 1:

after reading the comments i put the following indexes on the table

CREATE INDEX open_time ON trade(open_time);
CREATE INDEX symbol ON trade(symbol);
CREATE INDEX end_price ON trade(open_price);

after adding this the query time is 240 ms is this the max?

altho i have noteced querying the beginging 40k rows the query time drops to 60ms
after that is rises to 240ms what is causing this?

[guilherme]

The perfect index for this query is a two-column index, with the column that is compared with = first:

CREATE INDEX ON trade (symbol, open_time);

If that is still slow, the EXPLAIN (ANALYZE, BUFFERS) output for the query should tell us why.