Re: Nested loops are killing throughput - Mailing list pgsql-sql

From Tom Lane
Subject Re: Nested loops are killing throughput
Date
Msg-id 15195.1158689872@sss.pgh.pa.us
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In response to Re: Nested loops are killing throughput  (CG <cgg007@yahoo.com>)
Responses Re: Nested loops are killing throughput
List pgsql-sql
CG <cgg007@yahoo.com> writes:
> I'm still getting the nested loop for a join.
> Nested Loop  (cost=100000000.00..100013378.98 rows=2206 width=145) (actual time=46.743..18202.318 rows=2225 loops=1)
>   ->  Index Scan using packet_user_idx on packet dp  (cost=0.00..88.03 rows=2206 width=125) (actual
time=42.263..124.519rows=2225 loops=1)
 
>         Index Cond: ((username)::text = 'joeuser'::text)
>   ->  Index Scan using packet_status_puuid_pkey on packet_status dps  (cost=0.00..6.01 rows=1 width=20) (actual
time=8.115..8.117rows=1 loops=2225)
 
>         Index Cond: ("outer".packet_uuid = dps.packet_uuid)
> Total runtime: 18205.880 ms

If packet_status is large, that seems like a perfectly reasonable plan
to me.  If not ... what data type is packet_uuid?  Is its equality op
marked mergeable or hashable?
        regards, tom lane


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