In my opinion this is the Achilles heel of the postgres optimizer. Row estimates should never return 1, unless the estimate is provably <=1. This is particularly a problem with join estimates. A dumb fix for this is to change clamp_join_row_est() to never return a value <2. This fixes most of my observed poor plans. The real fix is to track uniqueness (or provable max rows) along with the selectivity estimate.
Here's the dumb fix. https://github.com/labkey-matthewb/postgres/commit/b1fd99f4deffbbf3db2172ccaba51a34f18d1b1a On Tue, Jan 23, 2018 at 7:59 AM, Laurent Martelli <martellilaur...@gmail.com > wrote: > I've have a look to the plan with pgadmin, and I think the problem is > rather here : > > -> Sort (cost=4997.11..4997.11 rows=1 width=69) (actual > time=27.427..28.896 rows=7359 loops=1) > Sort Key: amendment.id > Sort Method: quicksort Memory: 1227kB > -> Nested Loop (cost=183.44..4997.10 rows=1 width=69) (actual > time=1.115..24.616 rows=7359 loops=1) > -> Nested Loop (cost=183.15..4996.59 rows=1 width=49) > (actual time=1.107..9.091 rows=7360 loops=1) > -> Index Scan using uk_3b1y5vw9gmh7u3jj8aa2uy0b9 on > contact_partner businessprovider (cost=0.42..8.44 rows=1 width=13) > (actual time=0.010..0.010 rows=1 loops=1) > Index Cond: ((business_provider_code)::text = > 'BRZH'::text) > -> Bitmap Heap Scan on contract_contract_line > contractline (cost=182.73..4907.58 rows=8057 width=52) (actual > time=1.086..5.231 rows=7360 loops=1) > Recheck Cond: (business_provider_partner = > businessprovider.id) > Heap Blocks: exact=3586 > -> Bitmap Index Scan on > contract_contract_line_business_provider_partner_idx > (cost=0.00..180.72 rows=8057 width=0) (actual time=0.655..0.655 > rows=7360 loops=1) > Index Cond: (business_provider_partner = > businessprovider.id) > -> Index Scan using contract_amendment_pkey on > contract_amendment amendment (cost=0.29..0.50 rows=1 width=28) > (actual time=0.001..0.002 rows=1 loops=7360) > Index Cond: (id = contractline.amendment) > > The bitmap scan on contract_contract_line is good (8057 vs 7360 rows), > and so is the index scan (1 row), but the JOIN with "contact_partner > businessProvider" should give the 8057 rows from the bitmap scan, > shouldn't it ? > > > 2018-01-23 16:38 GMT+01:00 Laurent Martelli <martellilaur...@gmail.com>: > > 2018-01-23 16:18 GMT+01:00 Justin Pryzby <pry...@telsasoft.com>: > >> On Tue, Jan 23, 2018 at 01:03:49PM +0100, Laurent Martelli wrote: > >> > >>> Here is the default plan : > >> > >> Can you resend without line breaks or paste a link to explain.depesz? > > > > I hope it's better like that. I've attached it too, just in case. > > > >> > >> The problem appears to be here: > >> > >> -> Nested Loop Left Join (cost=32067.09..39197.85 rows=1 width=276) > (actual time=342.725..340775.031 rows=7359 loops=1) > >> Join Filter: (sh.share_holder_partner = partner.id) > >> Rows Removed by Join Filter: 204915707 > >> > >> Justin > > > > > > > > QUERY PLAN > > ------------------------------------------------------------ > ------------------------------------------------------------ > ------------------------------------------------------------ > ------------------------------------------------------------ > ------------------------------------------------------------ > ------------------------------------------------------------------ > > Sort (cost=39200.76..39200.76 rows=1 width=1066) (actual > > time=341273.300..341274.244 rows=7359 loops=1) > > Sort Key: ((array_agg(subscribed_power.subscribed_power))[1]) DESC, > > status.name, contractline.id > > Sort Method: quicksort Memory: 3930kB > > -> Nested Loop Left Join (cost=32069.19..39200.75 rows=1 > > width=1066) (actual time=342.806..341203.151 rows=7359 loops=1) > > -> Nested Loop Left Join (cost=32069.05..39200.50 rows=1 > > width=508) (actual time=342.784..341102.848 rows=7359 loops=1) > > -> Nested Loop Left Join (cost=32068.77..39200.20 > > rows=1 width=500) (actual time=342.778..341070.310 rows=7359 loops=1) > > -> Nested Loop Left Join > > (cost=32068.64..39200.04 rows=1 width=507) (actual > > time=342.776..341058.256 rows=7359 loops=1) > > Join Filter: (cca.address = adr_contact.id) > > Rows Removed by Join Filter: 2254 > > -> Nested Loop Left Join > > (cost=32068.22..39199.55 rows=1 width=515) (actual > > time=342.767..340997.058 rows=7359 loops=1) > > -> Nested Loop Left Join > > (cost=32067.79..39198.84 rows=1 width=447) (actual > > time=342.753..340932.286 rows=7359 loops=1) > > -> Nested Loop Left Join > > (cost=32067.65..39198.67 rows=1 width=421) (actual > > time=342.748..340896.132 rows=7359 loops=1) > > -> Nested Loop Left Join > > (cost=32067.23..39198.01 rows=1 width=279) (actual > > time=342.739..340821.987 rows=7359 loops=1) > > -> Nested Loop > > Left Join (cost=32067.09..39197.85 rows=1 width=276) (actual > > time=342.725..340775.031 rows=7359 loops=1) > > Join Filter: > > (sh.share_holder_partner = partner.id) > > Rows Removed > > by Join Filter: 204915707 > > -> Nested > > Loop Left Join (cost=28514.61..34092.46 rows=1 width=244) (actual > > time=287.323..610.192 rows=7359 loops=1) > > -> > > Nested Loop Left Join (cost=28514.47..34092.30 rows=1 width=239) > > (actual time=287.318..573.234 rows=7359 loops=1) > > > > -> Hash Right Join (cost=28513.48..34090.65 rows=1 width=159) > > (actual time=287.293..379.564 rows=7359 loops=1) > > > > Hash Cond: (ws.contract_line = contractline.id) > > > > -> Seq Scan on shareholder_web_subscription ws > > (cost=0.00..5378.84 rows=52884 width=24) (actual time=0.006..12.307 > > rows=52884 loops=1) > > > > -> Hash (cost=28513.47..28513.47 rows=1 width=143) (actual > > time=287.243..287.243 rows=7359 loops=1) > > > > Buckets: 8192 (originally 1024) Batches: 1 (originally 1) > > Memory Usage: 1173kB > > > > -> Nested Loop Left Join (cost=17456.16..28513.47 rows=1 > > width=143) (actual time=85.005..284.689 rows=7359 loops=1) > > > > -> Nested Loop (cost=17456.03..28513.31 rows=1 > > width=148) (actual time=85.000..276.599 rows=7359 loops=1) > > > > -> Nested Loop Left Join > > (cost=17455.73..28512.84 rows=1 width=148) (actual > > time=84.993..261.954 rows=7359 loops=1) > > > > -> Nested Loop (cost=17455.60..28512.67 > > rows=1 width=140) (actual time=84.989..253.715 rows=7359 loops=1) > > > > -> Nested Loop > > (cost=17455.18..28511.93 rows=1 width=93) (actual time=84.981..230.977 > > rows=7359 loops=1) > > > > -> Merge Right Join > > (cost=17454.89..28511.52 rows=1 width=93) (actual time=84.974..211.200 > > rows=7359 loops=1) > > > > Merge Cond: > > (subscribed_power.amendment = amendment.id) > > > > -> GroupAggregate > > (cost=12457.78..22574.03 rows=75229 width=168) (actual > > time=57.500..175.674 rows=83432 loops=1) > > > > Group Key: > > subscribed_power.amendment > > > > -> Merge Join > > (cost=12457.78..20764.08 rows=173917 width=12) (actual > > time=57.479..129.530 rows=87938 loops=1) > > > > Merge Cond: > > (subscribed_power.amendment = amendment_1.id) > > > > -> Index > > Scan using contract_subscribed_power_amendment_idx on > > contract_subscribed_power subscribed_power (cost=0.42..13523.09 > > rows=173917 width=12) (actual time=0.009..33.704 rows=87963 loops=1) > > > > -> Sort > > (cost=12457.36..12666.43 rows=83629 width=8) (actual > > time=57.467..67.071 rows=88019 loops=1) > > > > Sort > > Key: amendment_1.id > > > > Sort > > Method: quicksort Memory: 6988kB > > > > -> > > Hash Join (cost=10.21..5619.97 rows=83629 width=8) (actual > > time=0.112..40.965 rows=83532 loops=1) > > > > > > Hash Cond: (amendment_1.pricing = pricing.id) > > > > > > -> Seq Scan on contract_amendment amendment_1 (cost=0.00..4460.29 > > rows=83629 width=16) (actual time=0.004..6.988 rows=83629 loops=1) > > > > > > -> Hash (cost=8.43..8.43 rows=142 width=8) (actual time=0.095..0.095 > > rows=141 loops=1) > > > > > > Buckets: 1024 Batches: 1 Memory Usage: 14kB > > > > > > -> Hash Join (cost=1.07..8.43 rows=142 width=8) (actual > > time=0.012..0.078 rows=141 loops=1) > > > > > > Hash Cond: (pricing.elec_range = elec_range.id) > > > > > > -> Seq Scan on pricing_pricing pricing (cost=0.00..5.42 > > rows=142 width=16) (actual time=0.003..0.015 rows=142 loops=1) > > > > > > -> Hash (cost=1.03..1.03 rows=3 width=8) (actual > > time=0.006..0.006 rows=3 loops=1) > > > > > > Buckets: 1024 Batches: 1 Memory Usage: 9kB > > > > > > -> Seq Scan on fluid_elec_range elec_range > > (cost=0.00..1.03 rows=3 width=8) (actual time=0.003..0.005 rows=3 > > loops=1) > > > > -> Sort > > (cost=4997.11..4997.11 rows=1 width=69) (actual time=27.427..28.896 > > rows=7359 loops=1) > > > > Sort Key: > > amendment.id > > > > Sort Method: > > quicksort Memory: 1227kB > > > > -> Nested Loop > > (cost=183.44..4997.10 rows=1 width=69) (actual time=1.115..24.616 > > rows=7359 loops=1) > > > > -> Nested > > Loop (cost=183.15..4996.59 rows=1 width=49) (actual time=1.107..9.091 > > rows=7360 loops=1) > > > > -> > > Index Scan using uk_3b1y5vw9gmh7u3jj8aa2uy0b9 on contact_partner > > businessprovider (cost=0.42..8.44 rows=1 width=13) (actual > > time=0.010..0.010 rows=1 loops=1) > > > > > > Index Cond: ((business_provider_code)::text = 'BRZH'::text) > > > > -> > > Bitmap Heap Scan on contract_contract_line contractline > > (cost=182.73..4907.58 rows=8057 width=52) (actual time=1.086..5.231 > > rows=7360 loops=1) > > > > > > Recheck Cond: (business_provider_partner = businessprovider.id) > > > > > > Heap Blocks: exact=3586 > > > > > > -> Bitmap Index Scan on > > contract_contract_line_business_provider_partner_idx > > (cost=0.00..180.72 rows=8057 width=0) (actual time=0.655..0.655 > > rows=7360 loops=1) > > > > > > Index Cond: (business_provider_partner = businessprovider.id) > > > > -> Index > > Scan using contract_amendment_pkey on contract_amendment amendment > > (cost=0.29..0.50 rows=1 width=28) (actual time=0.001..0.002 rows=1 > > loops=7360) > > > > Index > > Cond: (id = contractline.amendment) > > > > -> Index Scan using > > contract_contract_pkey on contract_contract contract (cost=0.29..0.40 > > rows=1 width=24) (actual time=0.002..0.002 rows=1 loops=7359) > > > > Index Cond: (id = > > contractline.contract) > > > > -> Index Scan using > > contact_partner_pkey on contact_partner partner (cost=0.42..0.74 > > rows=1 width=55) (actual time=0.002..0.002 rows=1 loops=7359) > > > > Index Cond: (id = > > contract.main_client_partner) > > > > -> Index Scan using > > contact_client_nature_pkey on contact_client_nature clientnature > > (cost=0.14..0.15 rows=1 width=24) (actual time=0.001..0.001 rows=1 > > loops=7359) > > > > Index Cond: (id = > > partner.client_nature) > > > > -> Index Scan using territory_mpt_pkey on > > territory_mpt mpt (cost=0.29..0.46 rows=1 width=16) (actual > > time=0.001..0.001 rows=1 loops=7359) > > > > Index Cond: (id = contractline.mpt) > > > > -> Index Scan using contract_user_segment_pkey on > > contract_user_segment usersegment (cost=0.14..0.15 rows=1 width=11) > > (actual time=0.001..0.001 rows=1 loops=7359) > > > > Index Cond: (id = amendment.user_segment) > > > > -> Nested Loop Left Join (cost=0.99..1.64 rows=1 width=96) (actual > > time=0.021..0.025 rows=1 loops=7359) > > > > -> Nested Loop Left Join (cost=0.85..1.35 rows=1 width=89) > > (actual time=0.017..0.020 rows=1 loops=7359) > > > > -> Nested Loop Left Join (cost=0.71..1.18 rows=1 width=76) > > (actual time=0.013..0.014 rows=1 loops=7359) > > > > -> Index Scan using contact_address_pkey on > > contact_address a (cost=0.42..0.85 rows=1 width=84) (actual > > time=0.005..0.006 rows=1 loops=7359) > > > > Index Cond: (mpt.address = id) > > > > -> Index Scan using territory_commune_pkey on > > territory_commune commune (cost=0.29..0.32 rows=1 width=16) (actual > > time=0.005..0.006 rows=1 loops=7359) > > > > Index Cond: (a.commune = id) > > > > -> Index Scan using territory_department_pkey on > > territory_department dept (cost=0.14..0.16 rows=1 width=37) (actual > > time=0.003..0.004 rows=1 loops=7359) > > > > Index Cond: (commune.department = id) > > > > -> Index Scan using territory_region_pkey on territory_region reg > > (cost=0.14..0.27 rows=1 width=23) (actual time=0.003..0.003 rows=1 > > loops=7359) > > > > Index Cond: (dept.region = id) > > -> > > Index Scan using administration_status_pkey on administration_status > > status (cost=0.14..0.16 rows=1 width=21) (actual time=0.003..0.003 > > rows=1 loops=7359) > > > > Index Cond: (id = contractline.status) > > -> > > GroupAggregate (cost=3552.48..4479.27 rows=27827 width=80) (actual > > time=0.006..44.205 rows=27846 loops=7359) > > Group > > Key: sh.share_holder_partner > > -> > > Sort (cost=3552.48..3624.85 rows=28948 width=17) (actual > > time=0.003..2.913 rows=28946 loops=7359) > > > > Sort Key: sh.share_holder_partner > > > > Sort Method: quicksort Memory: 3030kB > > > > -> Hash Join (cost=2.23..1407.26 rows=28948 width=17) (actual > > time=0.024..12.296 rows=28946 loops=1) > > > > Hash Cond: (sh.company = sh_coop.id) > > > > -> Seq Scan on shareholder_share_holder sh (cost=0.00..1007.00 > > rows=28948 width=20) (actual time=0.007..5.495 rows=28946 loops=1) > > > > Filter: (nb_share > 0) > > > > Rows Removed by Filter: 1934 > > > > -> Hash (cost=2.10..2.10 rows=10 width=13) (actual > > time=0.009..0.009 rows=10 loops=1) > > > > Buckets: 1024 Batches: 1 Memory Usage: 9kB > > > > -> Seq Scan on contact_company sh_coop (cost=0.00..2.10 > > rows=10 width=13) (actual time=0.003..0.006 rows=10 loops=1) > > -> Index Scan > > using crm_origin_pkey on crm_origin co (cost=0.14..0.16 rows=1 > > width=19) (actual time=0.004..0.004 rows=1 loops=7359) > > Index Cond: > > (id = ws.how_meet_enercoop) > > -> Index Scan using > > contact_contact_pkey on contact_contact mc (cost=0.42..0.65 rows=1 > > width=150) (actual time=0.007..0.008 rows=1 loops=7359) > > Index Cond: > > (partner.main_contact = id) > > -> Index Scan using > > contact_title_pkey on contact_title title (cost=0.14..0.16 rows=1 > > width=42) (actual time=0.003..0.003 rows=1 loops=7359) > > Index Cond: (mc.title = id) > > -> Index Scan using > > contact_address_pkey on contact_address adr_contact (cost=0.43..0.70 > > rows=1 width=68) (actual time=0.005..0.005 rows=1 loops=7359) > > Index Cond: (id = CASE WHEN > > (CASE WHEN ((partner.person_category_select)::text = > > 'naturalPerson'::text) THEN 'P'::text WHEN > > ((partner.person_category_select)::text = 'legalPerson'::text) THEN > > 'M'::text ELSE '?????'::text END = 'P'::text) THEN > > COALESCE(mc.address, mc.address_pro) ELSE COALESCE(mc.address_pro, > > mc.address) END) > > -> Index Scan using > > contact_contact_address_contact_idx on contact_contact_address cca > > (cost=0.42..0.48 rows=1 width=24) (actual time=0.006..0.006 rows=1 > > loops=7359) > > Index Cond: (contact = mc.id) > > -> Index Scan using > > contact_contact_address_status_pkey on contact_contact_address_status > > npai (cost=0.13..0.15 rows=1 width=9) (actual time=0.000..0.000 > > rows=0 loops=7359) > > Index Cond: (cca.contact_address_status = id) > > -> Index Scan using > > crm_crm_request_original_contract_line_idx on crm_crm_request > > mesrequest (cost=0.28..0.29 rows=1 width=16) (actual > > time=0.003..0.003 rows=0 loops=7359) > > Index Cond: (original_contract_line = > contractline.id) > > -> Index Scan using sale_product_sub_family_pkey on > > sale_product_sub_family mesproductsubfamily (cost=0.14..0.20 rows=1 > > width=62) (actual time=0.000..0.000 rows=0 loops=7359) > > Index Cond: (id = mesrequest.product_sub_family) > > Filter: (new_contract_ok IS TRUE) > > Planning time: 21.106 ms > > Execution time: 341275.027 ms > > (118 lignes) > > > > > > -- > > http://www.laurentmartelli.com // http://www.imprimart.fr > > > > -- > http://www.laurentmartelli.com // http://www.imprimart.fr > >
