Hi folks.
I have the query below which when run takes approx 3 seconds. However when I
add the condition 'and w_ws_id = 10' onto the end changes to 30+ seconds.
Can anyone see why? I've included the explain for the long select.
select w_vin as key, w_vin, v_o_number as vista, v_status,
s_stock_no, s_customer_order,
coalesce(d.r_registration, p.r_registration, w_reg_no) as
reg_no,w_arrival,
w_updated::date,CURRENT_DATE-w_created::date as age, w_model,
w_radio_code, w_key_no, w_inspected, w_damage,
w_walon_repair,w_collect_date, w_despatch_date, w_sheet,
w_plates, w_accessories,
coalesce(p.d_des, d.d_des) as d_des,
coalesce(p.de_des, d.de_des) as de_des,
p.r_id as pdi,
d.r_id as delivery,
o.o_id, o.state
from walon
left outer join request_details p on p.t_id = 'P' and
substring(p.r_chassis from '(.{11}$)') = w_vin
left outer join request_details d on d.t_id = 'D' and
substring(d.r_chassis from '(.{11}$)') = w_vin
left outer join order_details o on
substring(o.o_vin from '(.{11}$)') = w_vin
left outer join stock s on substring(s.s_vin from '(.{11}$)') = w_vin
left outer join vista v on v.v_vin = w_vin
where w_hide = 0.
--
Gary Stainburn
This email does not contain private or confidential material as it
may be snooped on by interested government parties for unknown
and undisclosed purposes - Regulation of Investigatory Powers Act, 2000
QUERY PLAN
Nested Loop Left Join (cost=14430.85..16251.57 rows=2 width=427)
- Nested Loop Left Join (cost=14430.85..16239.49 rows=2 width=405)
Join Filter: (substring((inner.s_vin)::text, '(.{11}$)'::text) =
(outer.w_vin)::text)
- Nested Loop Left Join (cost=13060.02..14496.72 rows=2 width=394)
Join Filter: (substring((inner.o_vin)::text,
'(.{11}$)'::text) = (outer.w_vin)::text)
- Nested Loop Left Join (cost=6635.38..7785.17 rows=2
width=352)
Join Filter: (substring((inner.r_chassis)::text,
'(.{11}$)'::text) = (outer.w_vin)::text)
- Nested Loop Left Join (cost=3617.97..4441.81 rows=2
width=246)
Join Filter: (substring((inner.r_chassis)::text,
'(.{11}$)'::text) = (outer.w_vin)::text)
- Index Scan using walon_hide_index on walon
(cost=0.00..85.04 rows=2 width=140)
Index Cond: (w_hide = 0)
Filter: (w_ws_id = 10)
- Materialize (cost=3617.97..3861.73 rows=8376
width=127)
- Subquery Scan p (cost=2372.95..3449.59
rows=8376 width=127)
- Merge Join (cost=2372.95..3365.83
rows=8376 width=196)
Merge Cond: (outer.r_id =
inner.r_id)
- Merge Left Join
(cost=208.05..954.29 rows=14895 width=20)
Merge Cond: (outer.r_id =
inner.co_r_id)
- Merge Left Join
(cost=105.13..810.93 rows=14895 width=12)
Merge Cond:
(outer.r_id = inner.co_r_id)
- Index Scan using
requests_pkey on requests r (cost=0.00..653.03 rows=14895 width=4)
- Sort
(cost=105.13..107.72 rows=1036 width=12)
Sort Key:
co.co_r_id
- Subquery
Scan co (cost=29.93..53.24 rows=1036 width=12)
-
HashAggregate (cost=29.93..42.88 rows=1036 width=4)
-
Seq Scan on comments (cost=0.00..24.62 rows=1062 width=4)
- Sort
(cost=102.93..103.46 rows=213 width=12)
Sort Key: cor.co_r_id
- Subquery Scan cor
(cost=89.90..94.69 rows=213 width=12)
-
HashAggregate (cost=89.90..92.56 rows=213 width=4)
- Hash
