此查询搜索通常使用 product_grouping ID 99999购买的product_groupings 。由于此查询会扇动到包含product_grouping 99999的所有订单，然后重新连接以计算每个product_grouping具有的次数已经订购，并进入前10名。
有没有办法加快查询速度？
SELECT product_groupings.*, count(product_groupings.id) AS product_groupings_count
FROM "product_groupings"
INNER JOIN "products" ON "product_groupings"."id" = "products"."product_grouping_id"
INNER JOIN "variants" ON "products"."id" = "variants"."product_id"
INNER JOIN "order_items" ON "variants"."id" = "order_items"."variant_id"
INNER JOIN "shipments" ON "order_items"."shipment_id" = "shipments"."id"
INNER JOIN "orders" ON "shipments"."order_id" = "orders"."id"
INNER JOIN "shipments" "shipments_often_purchased_with_join" ON "orders"."id" = "shipments_often_purchased_with_join"."order_id"
INNER JOIN "order_items" "order_items_often_purchased_with_join" ON "shipments_often_purchased_with_join"."id" = "order_items_often_purchased_with_join"."shipment_id"
INNER JOIN "variants" "variants_often_purchased_with_join" ON "order_items_often_purchased_with_join"."variant_id" = "variants_often_purchased_with_join"."id"
INNER JOIN "products" "products_often_purchased_with_join" ON "variants_often_purchased_with_join"."product_id" = "products_often_purchased_with_join"."id"
WHERE "products_often_purchased_with_join"."product_grouping_id" = 99999 AND (product_groupings.id != 99999) AND "product_groupings"."state" = 'active' AND ("shipments"."state" NOT IN ('pending', 'cancelled'))
GROUP BY product_groupings.id
ORDER BY product_groupings_count desc LIMIT 10
模式：
CREATE TABLE product_groupings (
id integer NOT NULL,
state character varying(255) DEFAULT 'active'::character varying,
brand_id integer,
product_content_id integer,
hierarchy_category_id integer,
hierarchy_subtype_id integer,
hierarchy_type_id integer,
product_type_id integer,
description text,
keywords text,
created_at timestamp without time zone,
updated_at timestamp without time zone
);
CREATE INDEX index_product_groupings_on_brand_id ON product_groupings USING btree (brand_id);
CREATE INDEX index_product_groupings_on_hierarchy_category_id ON product_groupings USING btree (hierarchy_category_id);
CREATE INDEX index_product_groupings_on_hierarchy_subtype_id ON product_groupings USING btree (hierarchy_subtype_id);
CREATE INDEX index_product_groupings_on_hierarchy_type_id ON product_groupings USING btree (hierarchy_type_id);
CREATE INDEX index_product_groupings_on_name ON product_groupings USING btree (name);
CREATE INDEX index_product_groupings_on_product_content_id ON product_groupings USING btree (product_content_id);
CREATE INDEX index_product_groupings_on_product_type_id ON product_groupings USING btree (product_type_id);
ALTER TABLE ONLY product_groupings
ADD CONSTRAINT product_groupings_pkey PRIMARY KEY (id);
CREATE TABLE products (
id integer NOT NULL,
name character varying(255) NOT NULL,
prototype_id integer,
deleted_at timestamp without time zone,
created_at timestamp without time zone,
updated_at timestamp without time zone,
item_volume character varying(255),
upc character varying(255),
state character varying(255),
volume_unit character varying(255),
volume_value numeric,
container_type character varying(255),
container_count integer,
upc_ext character varying(8),
product_grouping_id integer,
short_pack_size character varying(255),
short_volume character varying(255),
additional_upcs character varying(255)[] DEFAULT '{}'::character varying[]
);
CREATE INDEX index_products_on_additional_upcs ON products USING gin (additional_upcs);
CREATE INDEX index_products_on_deleted_at ON products USING btree (deleted_at);
CREATE INDEX index_products_on_name ON products USING btree (name);
CREATE INDEX index_products_on_product_grouping_id ON products USING btree (product_grouping_id);
CREATE INDEX index_products_on_prototype_id ON products USING btree (prototype_id);
CREATE INDEX index_products_on_upc ON products USING btree (upc);
ALTER TABLE ONLY products
ADD CONSTRAINT products_pkey PRIMARY KEY (id);
CREATE TABLE variants (
id integer NOT NULL,
product_id integer NOT NULL,
sku character varying(255) NOT NULL,
name character varying(255),
price numeric(8,2) DEFAULT 0.0 NOT NULL,
deleted_at timestamp without time zone,
supplier_id integer,
created_at timestamp without time zone,
updated_at timestamp without time zone,
inventory_id integer,
product_active boolean DEFAULT false NOT NULL,
original_name character varying(255),
original_item_volume character varying(255),
protected boolean DEFAULT false NOT NULL,
sale_price numeric(8,2) DEFAULT 0.0 NOT NULL
);
CREATE INDEX index_variants_on_inventory_id ON variants USING btree (inventory_id);
CREATE INDEX index_variants_on_product_id_and_deleted_at ON variants USING btree (product_id, deleted_at);
CREATE INDEX index_variants_on_sku ON variants USING btree (sku);
CREATE INDEX index_variants_on_state_attributes ON variants USING btree (deleted_at, product_active, protected, id);
CREATE INDEX index_variants_on_supplier_id ON variants USING btree (supplier_id);
ALTER TABLE ONLY variants
ADD CONSTRAINT variants_pkey PRIMARY KEY (id);
CREATE TABLE order_items (
id integer NOT NULL,
price numeric(8,2),
total numeric(8,2),
variant_id integer NOT NULL,
shipment_id integer,
created_at timestamp without time zone,
updated_at timestamp without time zone,
quantity integer DEFAULT 1
);
CREATE INDEX index_order_items_on_shipment_id ON order_items USING btree (shipment_id);
CREATE INDEX index_order_items_on_variant_id ON order_items USING btree (variant_id);
ALTER TABLE ONLY order_items
ADD CONSTRAINT order_items_pkey PRIMARY KEY (id);
CREATE TABLE shipments (
id integer NOT NULL,
order_id integer,
shipping_method_id integer NOT NULL,
number character varying,
state character varying(255) DEFAULT 'pending'::character varying NOT NULL,
created_at timestamp without time zone,
updated_at timestamp without time zone,
supplier_id integer,
confirmed_at timestamp without time zone,
canceled_at timestamp without time zone,
out_of_hours boolean DEFAULT false NOT NULL,
delivered_at timestamp without time zone,
uuid uuid DEFAULT uuid_generate_v4()
);
CREATE INDEX index_shipments_on_order_id_and_supplier_id ON shipments USING btree (order_id, supplier_id);
CREATE INDEX index_shipments_on_state ON shipments USING btree (state);
CREATE INDEX index_shipments_on_supplier_id ON shipments USING btree (supplier_id);
ALTER TABLE ONLY shipments
ADD CONSTRAINT shipments_pkey PRIMARY KEY (id);
CREATE TABLE orders (
id integer NOT NULL,
number character varying(255),
ip_address character varying(255),
state character varying(255),
ship_address_id integer,
active boolean DEFAULT true NOT NULL,
completed_at timestamp without time zone,
created_at timestamp without time zone,
updated_at timestamp without time zone,
tip_amount numeric(8,2) DEFAULT 0.0,
confirmed_at timestamp without time zone,
delivery_notes text,
cancelled_at timestamp without time zone,
courier boolean DEFAULT false NOT NULL,
scheduled_for timestamp without time zone,
client character varying(255),
subscription_id character varying(255),
pickup_detail_id integer,
);
CREATE INDEX index_orders_on_bill_address_id ON orders USING btree (bill_address_id);
CREATE INDEX index_orders_on_completed_at ON orders USING btree (completed_at);
CREATE UNIQUE INDEX index_orders_on_number ON orders USING btree (number);
CREATE INDEX index_orders_on_ship_address_id ON orders USING btree (ship_address_id);
CREATE INDEX index_orders_on_state ON orders USING btree (state);
ALTER TABLE ONLY orders
ADD CONSTRAINT orders_pkey PRIMARY KEY (id);
查询计划：
Limit (cost=685117.80..685117.81 rows=10 width=595) (actual time=33659.659..33659.661 rows=10 loops=1)
Output: product_groupings.id, product_groupings.featured, product_groupings.searchable, product_groupings.state, product_groupings.brand_id, product_groupings.product_content_id, product_groupings.hierarchy_category_id, product_groupings.hierarchy_subtype_id, product_groupings.hierarchy_type_id, product_groupings.product_type_id, product_groupings.meta_description, product_groupings.meta_keywords, product_groupings.name, product_groupings.permalink, product_groupings.description, product_groupings.keywords, product_groupings.created_at, product_groupings.updated_at, product_groupings.tax_category_id, product_groupings.trimmed_name, (count(product_groupings.id))
Buffers: shared hit=259132 read=85657, temp read=30892 written=30886
I/O Timings: read=5542.213
-> Sort (cost=685117.80..685117.81 rows=14 width=595) (actual time=33659.658..33659.659 rows=10 loops=1)
Output: product_groupings.id, product_groupings.featured, product_groupings.searchable, product_groupings.state, product_groupings.brand_id, product_groupings.product_content_id, product_groupings.hierarchy_category_id, product_groupings.hierarchy_subtype_id, product_groupings.hierarchy_type_id, product_groupings.product_type_id, product_groupings.meta_description, product_groupings.meta_keywords, product_groupings.name, product_groupings.permalink, product_groupings.description, product_groupings.keywords, product_groupings.created_at, product_groupings.updated_at, product_groupings.tax_category_id, product_groupings.trimmed_name, (count(product_groupings.id))
Sort Key: (count(product_groupings.id))
Sort Method: top-N heapsort Memory: 30kB
Buffers: shared hit=259132 read=85657, temp read=30892 written=30886
I/O Timings: read=5542.213
-> HashAggregate (cost=685117.71..685117.75 rows=14 width=595) (actual time=33659.407..33659.491 rows=122 loops=1)
Output: product_groupings.id, product_groupings.featured, product_groupings.searchable, product_groupings.state, product_groupings.brand_id, product_groupings.product_content_id, product_groupings.hierarchy_category_id, product_groupings.hierarchy_subtype_id, product_groupings.hierarchy_type_id, product_groupings.product_type_id, product_groupings.meta_description, product_groupings.meta_keywords, product_groupings.name, product_groupings.permalink, product_groupings.description, product_groupings.keywords, product_groupings.created_at, product_groupings.updated_at, product_groupings.tax_category_id, product_groupings.trimmed_name, count(product_groupings.id)
Buffers: shared hit=259129 read=85657, temp read=30892 written=30886
I/O Timings: read=5542.213
-> Hash Join (cost=453037.24..685117.69 rows=14 width=595) (actual time=26019.889..33658.886 rows=181 loops=1)
Output: product_groupings.id, product_groupings.featured, product_groupings.searchable, product_groupings.state, product_groupings.brand_id, product_groupings.product_content_id, product_groupings.hierarchy_category_id, product_groupings.hierarchy_subtype_id, product_groupings.hierarchy_type_id, product_groupings.product_type_id, product_groupings.meta_description, product_groupings.meta_keywords, product_groupings.name, product_groupings.permalink, product_groupings.description, product_groupings.keywords, product_groupings.created_at, product_groupings.updated_at, product_groupings.tax_category_id, product_groupings.trimmed_name
Hash Cond: (order_items_often_purchased_with_join.variant_id = variants_often_purchased_with_join.id)
Buffers: shared hit=259129 read=85657, temp read=30892 written=30886
I/O Timings: read=5542.213
-> Hash Join (cost=452970.37..681530.70 rows=4693428 width=599) (actual time=22306.463..32908.056 rows=8417034 loops=1)
Output: product_groupings.id, product_groupings.featured, product_groupings.searchable, product_groupings.state, product_groupings.brand_id, product_groupings.product_content_id, product_groupings.hierarchy_category_id, product_groupings.hierarchy_subtype_id, product_groupings.hierarchy_type_id, product_groupings.product_type_id, product_groupings.meta_description, product_groupings.meta_keywords, product_groupings.name, product_groupings.permalink, product_groupings.description, product_groupings.keywords, product_groupings.created_at, product_groupings.updated_at, product_groupings.tax_category_id, product_groupings.trimmed_name, order_items_often_purchased_with_join.variant_id
Hash Cond: (products.product_grouping_id = product_groupings.id)
Buffers: shared hit=259080 read=85650, temp read=30892 written=30886
I/O Timings: read=5540.529
-> Hash Join (cost=381952.28..493289.49 rows=5047613 width=8) (actual time=21028.128..25416.504 rows=8417518 loops=1)
Output: products.product_grouping_id, order_items_often_purchased_with_join.variant_id
Hash Cond: (order_items_often_purchased_with_join.shipment_id = shipments_often_purchased_with_join.id)
Buffers: shared hit=249520 read=77729
I/O Timings: read=5134.878
-> Seq Scan on public.order_items order_items_often_purchased_with_join (cost=0.00..82689.54 rows=4910847 width=8) (actual time=0.003..1061.456 rows=4909856 loops=1)
Output: order_items_often_purchased_with_join.shipment_id, order_items_often_purchased_with_join.variant_id
Buffers: shared hit=67957
-> Hash (cost=373991.27..373991.27 rows=2274574 width=8) (actual time=21027.220..21027.220 rows=2117538 loops=1)
Output: products.product_grouping_id, shipments_often_purchased_with_join.id
Buckets: 262144 Batches: 1 Memory Usage: 82717kB
Buffers: shared hit=181563 read=77729
I/O Timings: read=5134.878
-> Hash Join (cost=249781.35..373991.27 rows=2274574 width=8) (actual time=10496.552..20383.404 rows=2117538 loops=1)
Output: products.product_grouping_id, shipments_often_purchased_with_join.id
Hash Cond: (shipments.order_id = orders.id)
Buffers: shared hit=181563 read=77729
I/O Timings: read=5134.878
-> Hash Join (cost=118183.04..233677.13 rows=1802577 width=8) (actual time=6080.516..14318.439 rows=1899610 loops=1)
Output: products.product_grouping_id, shipments.order_id
Hash Cond: (variants.product_id = products.id)
Buffers: shared hit=107220 read=55876
I/O Timings: read=5033.540
-> Hash Join (cost=83249.21..190181.06 rows=1802577 width=8) (actual time=4526.391..11330.434 rows=1899808 loops=1)
Output: variants.product_id, shipments.order_id
Hash Cond: (order_items.variant_id = variants.id)
Buffers: shared hit=88026 read=44439
I/O Timings: read=4009.465
-> Hash Join (cost=40902.30..138821.27 rows=1802577 width=8) (actual time=3665.477..8553.803 rows=1899816 loops=1)
Output: order_items.variant_id, shipments.order_id
Hash Cond: (order_items.shipment_id = shipments.id)
Buffers: shared hit=56654 read=43022
I/O Timings: read=3872.065
-> Seq Scan on public.order_items (cost=0.00..82689.54 rows=4910847 width=8) (actual time=0.003..2338.108 rows=4909856 loops=1)
Output: order_items.variant_id, order_items.shipment_id
Buffers: shared hit=55987 read=11970
I/O Timings: read=1059.971
-> Hash (cost=38059.31..38059.31 rows=812284 width=8) (actual time=3664.973..3664.973 rows=834713 loops=1)
Output: shipments.id, shipments.order_id
Buckets: 131072 Batches: 1 Memory Usage: 32606kB
Buffers: shared hit=667 read=31052
I/O Timings: read=2812.094
-> Seq Scan on public.shipments (cost=0.00..38059.31 rows=812284 width=8) (actual time=0.017..3393.420 rows=834713 loops=1)
Output: shipments.id, shipments.order_id
Filter: ((shipments.state)::text <> ALL ('{pending,cancelled}'::text[]))
Rows Removed by Filter: 1013053
Buffers: shared hit=667 read=31052
I/O Timings: read=2812.094
-> Hash (cost=37200.34..37200.34 rows=1470448 width=8) (actual time=859.887..859.887 rows=1555657 loops=1)
Output: variants.product_id, variants.id
Buckets: 262144 Batches: 1 Memory Usage: 60768kB
Buffers: shared hit=31372 read=1417
I/O Timings: read=137.400
-> Seq Scan on public.variants (cost=0.00..37200.34 rows=1470448 width=8) (actual time=0.009..479.528 rows=1555657 loops=1)
Output: variants.product_id, variants.id
Buffers: shared hit=31372 read=1417
I/O Timings: read=137.400
-> Hash (cost=32616.92..32616.92 rows=661973 width=8) (actual time=1553.664..1553.664 rows=688697 loops=1)
Output: products.product_grouping_id, products.id
Buckets: 131072 Batches: 1 Memory Usage: 26903kB
Buffers: shared hit=19194 read=11437
I/O Timings: read=1024.075
-> Seq Scan on public.products (cost=0.00..32616.92 rows=661973 width=8) (actual time=0.011..1375.757 rows=688697 loops=1)
Output: products.product_grouping_id, products.id
Buffers: shared hit=19194 read=11437
I/O Timings: read=1024.075
-> Hash (cost=125258.00..125258.00 rows=1811516 width=12) (actual time=4415.081..4415.081 rows=1847746 loops=1)
Output: orders.id, shipments_often_purchased_with_join.order_id, shipments_often_purchased_with_join.id
Buckets: 262144 Batches: 1 Memory Usage: 79396kB
Buffers: shared hit=74343 read=21853
I/O Timings: read=101.338
-> Hash Join (cost=78141.12..125258.00 rows=1811516 width=12) (actual time=1043.228..3875.433 rows=1847746 loops=1)
Output: orders.id, shipments_often_purchased_with_join.order_id, shipments_often_purchased_with_join.id
Hash Cond: (shipments_often_purchased_with_join.order_id = orders.id)
Buffers: shared hit=74343 read=21853
I/O Timings: read=101.338
-> Seq Scan on public.shipments shipments_often_purchased_with_join (cost=0.00..37153.55 rows=1811516 width=8) (actual time=0.006..413.785 rows=1847766 loops=1)
Output: shipments_often_purchased_with_join.order_id, shipments_often_purchased_with_join.id
Buffers: shared hit=31719
-> Hash (cost=70783.52..70783.52 rows=2102172 width=4) (actual time=1042.239..1042.239 rows=2097229 loops=1)
Output: orders.id
Buckets: 262144 Batches: 1 Memory Usage: 73731kB
Buffers: shared hit=42624 read=21853
I/O Timings: read=101.338
-> Seq Scan on public.orders (cost=0.00..70783.52 rows=2102172 width=4) (actual time=0.012..553.606 rows=2097229 loops=1)
Output: orders.id
Buffers: shared hit=42624 read=21853
I/O Timings: read=101.338
-> Hash (cost=20222.66..20222.66 rows=637552 width=595) (actual time=1278.121..1278.121 rows=626176 loops=1)
Output: product_groupings.id, product_groupings.featured, product_groupings.searchable, product_groupings.state, product_groupings.brand_id, product_groupings.product_content_id, product_groupings.hierarchy_category_id, product_groupings.hierarchy_subtype_id, product_groupings.hierarchy_type_id, product_groupings.product_type_id, product_groupings.meta_description, product_groupings.meta_keywords, product_groupings.name, product_groupings.permalink, product_groupings.description, product_groupings.keywords, product_groupings.created_at, product_groupings.updated_at, product_groupings.tax_category_id, product_groupings.trimmed_name
Buckets: 16384 Batches: 4 Memory Usage: 29780kB
Buffers: shared hit=9559 read=7921, temp written=10448
I/O Timings: read=405.651
-> Seq Scan on public.product_groupings (cost=0.00..20222.66 rows=637552 width=595) (actual time=0.020..873.844 rows=626176 loops=1)
Output: product_groupings.id, product_groupings.featured, product_groupings.searchable, product_groupings.state, product_groupings.brand_id, product_groupings.product_content_id, product_groupings.hierarchy_category_id, product_groupings.hierarchy_subtype_id, product_groupings.hierarchy_type_id, product_groupings.product_type_id, product_groupings.meta_description, product_groupings.meta_keywords, product_groupings.name, product_groupings.permalink, product_groupings.description, product_groupings.keywords, product_groupings.created_at, product_groupings.updated_at, product_groupings.tax_category_id, product_groupings.trimmed_name
Filter: ((product_groupings.id <> 99999) AND ((product_groupings.state)::text = 'active'::text))
Rows Removed by Filter: 48650
Buffers: shared hit=9559 read=7921
I/O Timings: read=405.651
-> Hash (cost=66.86..66.86 rows=4 width=4) (actual time=2.223..2.223 rows=30 loops=1)
Output: variants_often_purchased_with_join.id
Buckets: 1024 Batches: 1 Memory Usage: 2kB
Buffers: shared hit=49 read=7
I/O Timings: read=1.684
-> Nested Loop (cost=0.17..66.86 rows=4 width=4) (actual time=0.715..2.211 rows=30 loops=1)
Output: variants_often_purchased_with_join.id
Buffers: shared hit=49 read=7
I/O Timings: read=1.684
-> Index Scan using index_products_on_product_grouping_id on public.products products_often_purchased_with_join (cost=0.08..5.58 rows=2 width=4) (actual time=0.074..0.659 rows=6 loops=1)
Output: products_often_purchased_with_join.id
Index Cond: (products_often_purchased_with_join.product_grouping_id = 99999)
Buffers: shared hit=5 read=4
I/O Timings: read=0.552
-> Index Scan using index_variants_on_product_id_and_deleted_at on public.variants variants_often_purchased_with_join (cost=0.09..30.60 rows=15 width=8) (actual time=0.222..0.256 rows=5 loops=6)
Output: variants_often_purchased_with_join.id, variants_often_purchased_with_join.product_id
Index Cond: (variants_often_purchased_with_join.product_id = products_often_purchased_with_join.id)
Buffers: shared hit=44 read=3
I/O Timings: read=1.132
Total runtime: 33705.142 ms
答案 0 :(得分：0)
使用子选择获得了大约20倍的吞吐量增加;
SELECT product_groupings.*, count(product_groupings.id) AS product_groupings_count
FROM "product_groupings"
INNER JOIN "products" ON "products"."product_grouping_id" = "product_groupings"."id"
INNER JOIN "variants" ON "variants"."product_id" = "products"."id"
INNER JOIN "order_items" ON "order_items"."variant_id" = "variants"."id"
INNER JOIN "shipments" ON "shipments"."id" = "order_items"."shipment_id"
WHERE ("product_groupings"."id" != 99999)
AND "product_groupings"."state" = 'active'
AND ("shipments"."state" NOT IN ('pending', 'cancelled'))
AND ("shipments"."order_id" IN (
SELECT "shipments"."order_id"
FROM "shipments"
INNER JOIN "order_items" ON "order_items"."shipment_id" = "shipments"."id"
INNER JOIN "variants" ON "variants"."id" = "order_items"."variant_id"
INNER JOIN "products" ON "products"."id" = "variants"."product_id"
WHERE "products"."product_grouping_id" = 99999 AND ("shipments"."state" NOT IN ('pending', 'cancelled'))
GROUP BY "shipments"."order_id"
ORDER BY "shipments"."order_id" ASC
))
GROUP BY product_groupings.id
ORDER BY product_groupings_count desc
LIMIT 10
虽然我欢迎任何进一步的优化。 ：）