In the below query both table has less than 1 million data. Can u tell me
the reason of this plan?
why its takin extensive cost , seq scan and sorting?? wat is Materialize?
select 1 from service_detail
left join non_service_detail on non_service_detail_service_id =
Merge Left Join (cost=62451.86..67379.08 rows=286789 width=0)
Merge Cond: (service_detail.service_detail_id =
-> Sort (cost=18610.57..18923.27 rows=125077 width=8)
Sort Key: service_detail.service_detail_id
-> Seq Scan on service_detail (cost=0.00..6309.77 rows=125077
-> Materialize (cost=43841.28..47426.15 rows=286789 width=8)
-> Sort (cost=43841.28..44558.26 rows=286789 width=8)
Sort Key: non_service_detail.non_service_detail_service_id
-> Seq Scan on non_service_detail (cost=0.00..13920.89
"Many of lifes failure are people who did not realize how close they were to
success when they gave up."
pgsql-performance by date
|Next:||From: Grzegorz Jaśkiewicz||Date: 2009-10-12 12:30:12|
|Subject: Re: Query performance|
|Previous:||From: Michal Vitecek||Date: 2009-10-12 09:23:39|
|Subject: Re: updating a row in a table with only one row|