How can I optimize these Postgres queries and DB performance? - performance

Question

I need some help in optimizing the following two queries which are almost similar but data selection is a little different. Here is my table definition
CREATE TABLE public.rates (
rate_id bigserial NOT NULL PRIMARY KEY,
prefix varchar(50),
rate_name varchar(30),
rate numeric(8,6),
intrastate_cost numeric(8,6),
interstate_cost numeric(8,6),
status char(3) DEFAULT 'act'::bpchar,
min_duration integer,
call_increment integer,
connection_cost numeric(8,6),
rate_type varchar(3) DEFAULT 'lcr'::character varying,
owner_type varchar(10),
start_date timestamp WITHOUT TIME ZONE,
end_date timestamp WITHOUT TIME ZONE,
rev integer,
ratecard_id integer,
/* Keys */
CONSTRAINT rates_pkey
PRIMARY KEY (id)
) WITH (
OIDS = FALSE
);
and two queries here I am using,
SELECT
rates.* ,
rc.ratecard_prefix ,
rc.default_lrn ,
rc.lrn_lookup_method ,
customers.customer_id ,
customers.balance ,
customers.channels AS customer_channels ,
customers.cps AS customer_cps ,
customers.balance AS customer_balance
FROM
rates
JOIN ratecards rc
ON rc.card_type = 'customer' AND
rc.ratecard_id = rates.ratecard_id
JOIN customers
ON rc.customer_id = customers.customer_id
WHERE
customers.status = 'act' AND
rc.status = 'act' AND
rc.customer_id = 'AB8KA191' AND
owner_type = 'customer' AND
'17606109973' LIKE concat (rc.ratecard_prefix, rates.prefix, '%') AND
rates.status = 'act' AND
now() BETWEEN rates. start_date AND
rates.end_date AND
customers.balance > 0
ORDER BY
LENGTH(PREFIX) DESC LIMIT 1;
and the second one,
SELECT
*
FROM
rates
JOIN ratecards rc
ON rc.card_type = 'carrier' AND
rc.ratecard_id = rates.ratecard_id
JOIN carriers
ON rc.carrier_id = carriers.carrier_id
JOIN carrier_switches cswitch
ON carriers.carrier_id = cswitch.carrier_id
WHERE
rates.intrastate_cost < 0.011648 AND
owner_type = 'carrier' AND
'16093960411' LIKE concat (rates.prefix, '%') AND
rates.status = 'act' AND
carriers.status = 'act' AND
now() BETWEEN rates.start_date AND
rates.end_date AND
rates.intrastate_cost <> -1 AND
cswitch.enabled = 't' AND
rates.rate_type = 'lrn' AND
rates.min_duration >= 6
ORDER BY
rates.intrastate_cost ASC,
LENGTH(rates.prefix) DESC,
cswitch.priority DESC
I created an index on field owner_type (not shown in schema above) but the query performance is not really what is expected. CPU usage becomes too high for the DB server and everything starts to slow down. Explain output for first query is here and the second one is here.
When the number of records are less in the table, things work fine, naturally, but when the number of records increases the CPU goes higher. I currently have around 341821 records in the table.
How can I improve the query execution or possibly change the query in order to speed things up?
I have set enable_bitmapscan = off because I think this gives me better performance. If set to on, every index scan is followed up with a Bitmap heap scan.
Things did ease up a little bit by changing the query to
SELECT
rates.*,
rc.ratecard_prefix,
rc.default_lrn,
rc.lrn_lookup_method,
customers.customer_id,
customers.balance,
customers.channels AS customer_channels,
customers.cps AS customer_cps,
customers.balance AS customer_balance
FROM
rates
JOIN ratecards rc
ON rc.card_type = 'customer' AND
rc.ratecard_id = rates.ratecard_id
JOIN customers
ON rc.customer_id = customers.customer_id
WHERE
customers.status = 'act' AND
rc.status = 'act' AND
rc.customer_id = 'AB8KA191' AND
owner_type = 'customer' AND
(CONCAT (rc.ratecard_prefix, rates.prefix) IN ('16026813306',
'1602681330',
'160268133',
'16026813',
'1602681',
'160268',
'16026',
'1602',
'160',
'16',
'1')) AND
rates.status = 'act' AND
now() BETWEEN rates.start_date AND
rates.end_date AND
customers.balance > 0
ORDER BY
LENGTH(PREFIX) DESC LIMIT 1
Postgres.conf is here
But still each Postgres process takes around 25%+ CPU. I now also using pgbouncer to utilize connection pooling but still not helping.