Re: Slow index scan - Pgsql 9.2

On Mon, Jan 9, 2017 at 6:06 PM, Patrick B <patrickbakerbr(at)gmail(dot)com> wrote:

> *Explain Analyze:*
>
> CTE Scan on "query_p" "qp" (cost=0.01..1060.57 rows=1 width=8) (actual
> time=4065.244..4065.246 rows=1 loops=1)
>
> CTE query_p
>
> -> Result (cost=0.00..0.01 rows=1 width=0) (actual time=0.002..0.003
> rows=1 loops=1)
>
> SubPlan 2
>
> -> Aggregate (cost=1060.53..1060.54 rows=1 width=0) (actual
> time=4065.229..4065.229 rows=1 loops=1)
>
> -> Index Scan using "clientid_customers" on "customers" "c"
> (cost=0.00..1059.01 rows=607 width=0) (actual time=9.105..4063.728
> rows=2513 loops=1)
>
> Index Cond: ("clientid" = "qp"."client_id")
>
> Filter: (NOT "deleted")
>
> Rows Removed by Filter: 1068
>
> Total runtime: 4075.753 ms
>
>
>
> Why a search for "client_id" is so slow??
>
>
​3,581​ individual pokes into the heap to confirm tuple visibility and
apply the deleted filter - that could indeed take a while.

David J.