Første trin:udfør præ-aggregering i underforespørgslen:
EXPLAINSELECT cal.theday, act.action_name, SUM(sub.the_count)FROM generate_series(current_date - interval '1 week', now(), interval '1 day') as cal(theday) -- kalender pseudo-tableCROSS JOIN (VÆRDIER ('page_open') , ('product_add') , ('product_buy') , ('product_event') , ('product_favourite') , ('product_open') , ('product_share') , (' session_start') ) AS act(action_name)LEFT JOIN ( SELECT es.action_name, date_trunc('day',es.date_update) as theday , COUNT(DISTINCT es.id ) AS the_count FROM event_statistics as es WHERE es.client_id =(SELECT c.id FRA klienter AS c WHERE c.client_name ='klientnavn') OG (es.date_update MELLEM (aktuel_dato - interval '1 uge') OG nu()) GRUPPER MED 1,2 ) sub ON cal.theday =sub .theday OG act.action_name =sub.action_name GRUPPER EFTER act.action_name,cal.thedayORDER BY act.action_name,cal.theday; Næste trin:Indsæt VALUES i en CTE og referer til den også i den samlede underforespørgsel. (forstærkningen afhænger af antallet af handlingsnavne, der kan springes over)
EXPLAINWITH act(action_name) AS (VALUES ('page_open') , ('product_add') , ('product_buy') , ('product_event') , ('product_favourite') , ('product_open') , ('product_share'), ('session_start') )SELECT cal.theday, act.action_name, SUM(sub.the_count)FROM generate_series(current_date - interval '1 week', now(), interval '1day') AS cal( theday)CROSS JOIN actLEFT JOIN ( SELECT es.action_name, date_trunc('day',es.date_update) AS theday , COUNT(DISTINCT es.id ) AS the_count FROM event_statistics AS es WHERE es.date_update BETWEEN (current_date - interval '1 ') AND now() AND EXISTS (SELECT * FROM clients cli WHERE cli.id=es.client_id AND cli.client_name ='client name') OG EKSISTERER (SELECT * FROM act WHERE act.action_name =es.action_name) GRUPPER EFTER 1,2 ) sub ON cal.theday =sub.theday OG act.action_name =sub.action_nameGROUP BY act.action_name,cal.thedayORDER BY act.action_name,cal.thed ay; OPDATERING:Brug af en fysisk (temp) tabel vil resultere i bedre estimater.
-- Sidste forsøg:materialiser det kartesiske produkt (tidsserier*handlingsnavn) -- i en midlertidig tabelCREATE TEMP TABLE grid AS(SELECT act.action_name, cal.thedayFROM gener_series(current_date - interval '1 week', now (), interval '1 dag') AS cal(theday)CROSS JOIN (VÆRDIER ('page_open') , ('product_add') , ('product_buy') , ('product_event') , ('product_favourite') , (' product_open'), ('product_share'), ('session_start') ) act(handlingsnavn) );OPRET UNIKT INDEKS PÅ gitter(handlingsnavn, dag); -- Indeks vil tvinge statistik til at blive indsamlet -- , og vil generere bedre estimater for antallet af rækkerCREATE INDEX iii ON hændelsesstatistik (action_name, date_update );VACUUM ANALYZE grid;VACUUM ANALYZE event_statistics;EXPLAINSELECT grid.action_name, grid.theday, SUM (sub.the_count) AS the_countFROM gridLEFT JOIN ( SELECT es.action_name, date_trunc('day',es.date_update) AS theday , COUNT(*) AS the_count FROM event_statistics AS es WHERE es.date_update BETWEEN (current_date - interval '1 week) ') AND now() AND EXISTS (SELECT * FROM clients cli WHERE cli.id=es.client_id AND cli.client_name ='client name') -- AND EXISTS (SELECT * FROM grid WHERE grid.action_name =es.action_name) GRUPPER EFTER 1,2 BESTIL EFTER 1,2 --nonsense! ) sub ON grid.theday =sub.theday AND grid.action_name =sub.action_name GRUPPER EFTER grid.action_name,grid.thedayORDER BY grid.action_name,grid.theday;
Opdatering nr. 3 (beklager, jeg opretter indekser på basistabellen/-tabellerne her. Du skal redigere. Jeg har også fjernet en-kolonnen på tidsstemplet)
-- forsøg #4:-- - materialisere det kartesiske produkt (tidsserier*handlingsnavn) -- - rense datointerval -logicCREATE TEMP TABLE grid AS(SELECT act.action_name, cal.theday::dateFROM gener_series( aktuel_dato - interval '1 uge', nu(), interval '1 dag') AS cal(theday)CROSS JOIN (VÆRDIER ('page_open') , ('product_add') , ('product_buy') , ('product_event') , ('product_favourite') , ('product_open') , ('product_share') , ('session_start') ) act(action_name) ); -- Indeks vil tvinge statistik til at blive indsamlet -- ,og vil generere bedre estimater for antallet af rækker-- CREATE UNIQUE INDEX ON grid(action_name, theday);-- CREATE INDEX iii ON event_statistics (action_name, date_update);CREATE UNIQUE INDEX ON grid(theday, action_name); CREATE INDEX iii ON event_statistics (date_update, action_name);VACUUM ANALYZE grid;VACUUM ANALYZE event_statistics;EXPLAINSELECT gr.action_name, gr.theday , COUNT(*) AS the_countFROM grid_events grLEFTistics es.action_name =gr.action_name AND date_trunc('day',es.date_update)::date =gr.theday OG es.date_update MELLEM (current_date - interval '1 week') AND current_dateJOIN-klienter cli ON cli.id=es. client_id OG cli.client_name ='klientnavn'GRUPPER EFTER gr.action_name,gr.thedayORDER BY 1,2; FORESPØRGSPLAN ------------------------------------------ -------------------------------------------------- -------------------------------------------------- ------------ GroupAggregate (pris=8.33..8.35 rows=1 width=17) Group Key:gr.action_name, gr.theday -> Sort (pris=8.33..8.34 rows=1) width=17) Sort Key:gr.action_name, gr.theday -> Nested Loop (pris=1.40..8.33 rows=1 width=17) -> Nested Loop (pris=1.31..7.78 rows=1 width=40) Join Filter:(es.client_id =cli.id) -> Index Scan ved hjælp af clients_client_name_key på klienters cli (cost=0.09..2.30 rows=1 width=4) Index Cond:(client_name ='client name'::text) -> Bitmap Heap Scan på event_statistics es (pris=1.22..5.45 rows=5 width=44) Tjek igen Cond:((date_update>=(('now'::cstring)::date - '7 days'::interval)) AND (date_update <=('now'::cstring)::date)) -> Bitmap Indeksscanning på iii (pris=0.00..1.22 rækker=5 bredde=0) Index Cond:((date_update>=(('now'::cstring)::date - '7 days'::interval)) AND ( date_update <=('now'::cstring)::date)) -> Kun indeks Scan med grid_theday_action_name_idx på grid gr (cost=0.09..0.54 rows=1 width=17) Index Cond:((theday =(date_trunc( 'day'::text, es.date_update)::date) AND (action_name =es.action_name))(15 rows)