Re: Performance Optimization for Dummies 2 - the SQL

On 10/5/06, Carlo Stonebanks <stonec(dot)register(at)sympatico(dot)ca> wrote:
> Hi Merlin,
>
> Here are the results. The query returned more rows (65 vs 12) because of the
> vague postal_code.

right. interestingly, the index didn't work properly anyways.
regardless, this is easily solvable but it looks like we might be
looking in the wrong place. do we have an multi-column index on
facility_address(facility_id, address_id)? did you run analyze?

> In reality, we would have to modify the postal_code logic to take advantage
> of full zip codes when they were avalable, not unconditionally truncate
> them.
>
> Carlo
>
> explain analyze select
> f.facility_id,
> fa.facility_address_id,
> a.address_id,
> f.facility_type_code,
> f.name,
> a.address,
> a.city,
> a.state_code,
> a.postal_code,
> a.country_code
> from
> mdx_core.facility as f
> join mdx_core.facility_address as fa
> on fa.facility_id = f.facility_id
> join mdx_core.address as a
> on a.address_id = fa.address_id
> where
> (a.country_code, a.state_code, mdx_core.zip_trunc(a.postal_code)) =
> ('US', 'IL', mdx_core.zip_trunc('60640-5759'))
> order by facility_id
>
> "Sort (cost=6474.78..6474.84 rows=25 width=103) (actual
> time=217.279..217.311 rows=65 loops=1)"
> " Sort Key: f.facility_id"
> " -> Nested Loop (cost=2728.54..6474.20 rows=25 width=103) (actual
> time=35.828..217.059 rows=65 loops=1)"
> " -> Hash Join (cost=2728.54..6384.81 rows=25 width=72) (actual
> time=35.801..216.117 rows=65 loops=1)"
> " Hash Cond: ("outer".address_id = "inner".address_id)"
> " -> Seq Scan on facility_address fa (cost=0.00..3014.68
> rows=128268 width=12) (actual time=0.007..99.072 rows=128268 loops=1)"
> " -> Hash (cost=2728.50..2728.50 rows=19 width=64) (actual
> time=33.618..33.618 rows=39 loops=1)"
> " -> Bitmap Heap Scan on address a (cost=48.07..2728.50
> rows=19 width=64) (actual time=2.569..33.491 rows=39 loops=1)"
> " Recheck Cond: ((country_code = 'US'::bpchar) AND
> ((state_code)::text = 'IL'::text))"
> " Filter: (mdx_core.zip_trunc(postal_code) =
> '60640'::text)"
> " -> Bitmap Index Scan on
> address_country_state_zip_trunc_idx (cost=0.00..48.07 rows=3846 width=0)
> (actual time=1.783..1.783 rows=3554 loops=1)"
> " Index Cond: ((country_code = 'US'::bpchar)
> AND ((state_code)::text = 'IL'::text))"
> " -> Index Scan using facility_pkey on facility f (cost=0.00..3.56
> rows=1 width=35) (actual time=0.009..0.010 rows=1 loops=65)"
> " Index Cond: ("outer".facility_id = f.facility_id)"
> "Total runtime: 217.520 ms"