在我的PostgreSQL 9.6.2数据库中，我有一个查询，可以根据某些股票数据构建一个计算字段表。它为表中的每一行计算1到10年的移动平均窗口，并在周期性调整中使用它。 CAPE，CAPB，CAPC，CAPS和CAPD，具体而言。
即，对于每一行，您计算过去1到10年的avg(earnings)，然后对其他几个变量进行相同的操作。
我目前正在使用横向连接来计算每一行的聚合，但事情非常缓慢，我不完全确定如何加快速度，无论是索引/重写查询等等。
例如，当我将查询分层为仅包含~25k行时，运行需要15分钟，这似乎太慢了。 （AWS免费套餐上的RDS）
-- Initialize Cyclical Adjustments
-- This query populates the database with numerous peak/min and CAPE type calculations.
-- We do this by selecting each valid row within the table by security then laterally
-- selecting the calculations for each of those rows. 'Valid' rows are determined by
-- date calculations that make sure every field that has insufficient data behind it
-- (several queries want 5+ years of time series data) is filled with NULL to avoid
-- inaccuracies.
WITH earliest_point AS (
SELECT
security_id,
min(date) as min_date
FROM bloomberg.security_data
GROUP BY security_id
)
SELECT
rec.record_id,
rec.security_id,
date,
-- Each of these cases decides if we have enough data in the database to populate the field. If there are at least
-- x years in the database (where x = 1:10) we do the price / aggregate computation. Otherwise, we shortcut to NULL.
-- NOTE: The NULLIF prevents us from dividing by zero.
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.max_earnings, 0) ELSE NULL END AS price_to_peak_earnings,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.min_earnings, 0) ELSE NULL END AS price_to_minimum_earnings,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.max_book, 0) ELSE NULL END AS price_to_peak_book,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.min_book, 0) ELSE NULL END AS price_to_minimum_book,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.max_sales, 0) ELSE NULL END AS price_to_peak_sales,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.min_sales, 0) ELSE NULL END AS price_to_minimum_sales,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.max_cashflow, 0) ELSE NULL END AS price_to_peak_cashflow,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.min_cashflow, 0) ELSE NULL END AS price_to_minimum_cashflow,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.max_dividends, 0) ELSE NULL END AS price_to_peak_dividends,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.min_dividends, 0) ELSE NULL END AS price_to_minimum_dividends,
CASE WHEN ep.min_date < rec.date - '1 years'::INTERVAL THEN price / NULLIF(ru.cap1_avg_earnings, 0) ELSE NULL END AS cape1,
CASE WHEN ep.min_date < rec.date - '2 years'::INTERVAL THEN price / NULLIF(ru.cap2_avg_earnings, 0) ELSE NULL END AS cape2,
CASE WHEN ep.min_date < rec.date - '2 years'::INTERVAL THEN price / NULLIF(ru.cap2_avg_earnings, 0) ELSE NULL END AS cape2,
CASE WHEN ep.min_date < rec.date - '3 years'::INTERVAL THEN price / NULLIF(ru.cap3_avg_earnings, 0) ELSE NULL END AS cape3,
CASE WHEN ep.min_date < rec.date - '4 years'::INTERVAL THEN price / NULLIF(ru.cap4_avg_earnings, 0) ELSE NULL END AS cape4,
CASE WHEN ep.min_date < rec.date - '5 years'::INTERVAL THEN price / NULLIF(ru.cap5_avg_earnings, 0) ELSE NULL END AS cape5,
CASE WHEN ep.min_date < rec.date - '6 years'::INTERVAL THEN price / NULLIF(ru.cap6_avg_earnings, 0) ELSE NULL END AS cape6,
CASE WHEN ep.min_date < rec.date - '7 years'::INTERVAL THEN price / NULLIF(ru.cap7_avg_earnings, 0) ELSE NULL END AS cape7,
CASE WHEN ep.min_date < rec.date - '8 years'::INTERVAL THEN price / NULLIF(ru.cap8_avg_earnings, 0) ELSE NULL END AS cape8,
CASE WHEN ep.min_date < rec.date - '9 years'::INTERVAL THEN price / NULLIF(ru.cap9_avg_earnings, 0) ELSE NULL END AS cape9,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.cap10_avg_earnings, 0) ELSE NULL END AS cape10,
CASE WHEN ep.min_date < rec.date - '1 years'::INTERVAL THEN price / NULLIF(ru.cap1_avg_book, 0) ELSE NULL END AS capb1,
CASE WHEN ep.min_date < rec.date - '2 years'::INTERVAL THEN price / NULLIF(ru.cap2_avg_book, 0) ELSE NULL END AS capb2,
CASE WHEN ep.min_date < rec.date - '3 years'::INTERVAL THEN price / NULLIF(ru.cap3_avg_book, 0) ELSE NULL END AS capb3,
CASE WHEN ep.min_date < rec.date - '4 years'::INTERVAL THEN price / NULLIF(ru.cap4_avg_book, 0) ELSE NULL END AS capb4,
CASE WHEN ep.min_date < rec.date - '5 years'::INTERVAL THEN price / NULLIF(ru.cap5_avg_book, 0) ELSE NULL END AS capb5,
CASE WHEN ep.min_date < rec.date - '6 years'::INTERVAL THEN price / NULLIF(ru.cap6_avg_book, 0) ELSE NULL END AS capb6,
CASE WHEN ep.min_date < rec.date - '7 years'::INTERVAL THEN price / NULLIF(ru.cap7_avg_book, 0) ELSE NULL END AS capb7,
CASE WHEN ep.min_date < rec.date - '8 years'::INTERVAL THEN price / NULLIF(ru.cap8_avg_book, 0) ELSE NULL END AS capb8,
CASE WHEN ep.min_date < rec.date - '9 years'::INTERVAL THEN price / NULLIF(ru.cap9_avg_book, 0) ELSE NULL END AS capb9,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.cap10_avg_book, 0) ELSE NULL END AS capb10,
CASE WHEN ep.min_date < rec.date - '1 years'::INTERVAL THEN price / NULLIF(ru.cap1_avg_sales, 0) ELSE NULL END AS caps1,
CASE WHEN ep.min_date < rec.date - '2 years'::INTERVAL THEN price / NULLIF(ru.cap2_avg_sales, 0) ELSE NULL END AS caps2,
CASE WHEN ep.min_date < rec.date - '3 years'::INTERVAL THEN price / NULLIF(ru.cap3_avg_sales, 0) ELSE NULL END AS caps3,
CASE WHEN ep.min_date < rec.date - '4 years'::INTERVAL THEN price / NULLIF(ru.cap4_avg_sales, 0) ELSE NULL END AS caps4,
CASE WHEN ep.min_date < rec.date - '5 years'::INTERVAL THEN price / NULLIF(ru.cap5_avg_sales, 0) ELSE NULL END AS caps5,
CASE WHEN ep.min_date < rec.date - '6 years'::INTERVAL THEN price / NULLIF(ru.cap6_avg_sales, 0) ELSE NULL END AS caps6,
CASE WHEN ep.min_date < rec.date - '7 years'::INTERVAL THEN price / NULLIF(ru.cap7_avg_sales, 0) ELSE NULL END AS caps7,
CASE WHEN ep.min_date < rec.date - '8 years'::INTERVAL THEN price / NULLIF(ru.cap8_avg_sales, 0) ELSE NULL END AS caps8,
CASE WHEN ep.min_date < rec.date - '9 years'::INTERVAL THEN price / NULLIF(ru.cap9_avg_sales, 0) ELSE NULL END AS caps9,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.cap10_avg_sales, 0) ELSE NULL END AS caps10,
CASE WHEN ep.min_date < rec.date - '1 years'::INTERVAL THEN price / NULLIF(ru.cap1_avg_cashflow, 0) ELSE NULL END AS capc1,
CASE WHEN ep.min_date < rec.date - '2 years'::INTERVAL THEN price / NULLIF(ru.cap2_avg_cashflow, 0) ELSE NULL END AS capc2,
CASE WHEN ep.min_date < rec.date - '3 years'::INTERVAL THEN price / NULLIF(ru.cap3_avg_cashflow, 0) ELSE NULL END AS capc3,
CASE WHEN ep.min_date < rec.date - '4 years'::INTERVAL THEN price / NULLIF(ru.cap4_avg_cashflow, 0) ELSE NULL END AS capc4,
CASE WHEN ep.min_date < rec.date - '5 years'::INTERVAL THEN price / NULLIF(ru.cap5_avg_cashflow, 0) ELSE NULL END AS capc5,
CASE WHEN ep.min_date < rec.date - '6 years'::INTERVAL THEN price / NULLIF(ru.cap6_avg_cashflow, 0) ELSE NULL END AS capc6,
CASE WHEN ep.min_date < rec.date - '7 years'::INTERVAL THEN price / NULLIF(ru.cap7_avg_cashflow, 0) ELSE NULL END AS capc7,
CASE WHEN ep.min_date < rec.date - '8 years'::INTERVAL THEN price / NULLIF(ru.cap8_avg_cashflow, 0) ELSE NULL END AS capc8,
CASE WHEN ep.min_date < rec.date - '9 years'::INTERVAL THEN price / NULLIF(ru.cap9_avg_cashflow, 0) ELSE NULL END AS capc9,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.cap10_avg_cashflow, 0) ELSE NULL END AS capc10,
CASE WHEN ep.min_date < rec.date - '1 years'::INTERVAL THEN price / NULLIF(ru.cap1_avg_dividends, 0) ELSE NULL END AS capd1,
CASE WHEN ep.min_date < rec.date - '2 years'::INTERVAL THEN price / NULLIF(ru.cap2_avg_dividends, 0) ELSE NULL END AS capd2,
CASE WHEN ep.min_date < rec.date - '3 years'::INTERVAL THEN price / NULLIF(ru.cap3_avg_dividends, 0) ELSE NULL END AS capd3,
CASE WHEN ep.min_date < rec.date - '4 years'::INTERVAL THEN price / NULLIF(ru.cap4_avg_dividends, 0) ELSE NULL END AS capd4,
CASE WHEN ep.min_date < rec.date - '5 years'::INTERVAL THEN price / NULLIF(ru.cap5_avg_dividends, 0) ELSE NULL END AS capd5,
CASE WHEN ep.min_date < rec.date - '6 years'::INTERVAL THEN price / NULLIF(ru.cap6_avg_dividends, 0) ELSE NULL END AS capd6,
CASE WHEN ep.min_date < rec.date - '7 years'::INTERVAL THEN price / NULLIF(ru.cap7_avg_dividends, 0) ELSE NULL END AS capd7,
CASE WHEN ep.min_date < rec.date - '8 years'::INTERVAL THEN price / NULLIF(ru.cap8_avg_dividends, 0) ELSE NULL END AS capd8,
CASE WHEN ep.min_date < rec.date - '9 years'::INTERVAL THEN price / NULLIF(ru.cap9_avg_dividends, 0) ELSE NULL END AS capd9,
CASE WHEN ep.min_date < rec.date - '10 years'::INTERVAL THEN price / NULLIF(ru.cap10_avg_dividends, 0) ELSE NULL END AS capd10
FROM bloomberg.security_data rec
-- Include the earliest point we have for this security in the record
JOIN earliest_point ep ON ep.security_id = rec.security_id,
-- LATERAL SELECT is executed for each row in the above query, with the row (rec) as a parameter
LATERAL
(
SELECT
-- Price to Peak/Minimum <field> calculations
max(earnings) AS max_earnings,
min(earnings) AS min_earnings,
max(book) AS max_book,
min(book) AS min_book,
max(sales) AS max_sales,
min(sales) AS min_sales,
max(cashflow) AS max_cashflow,
min(cashflow) AS min_cashflow,
max(dividends) AS max_dividends,
min(dividends) AS min_dividends,
-- Each of the following computes the aggregates for the
-- CAPE/B/S/C/D cyclical adjustments.
avg(earnings) FILTER (WHERE date >= rec.date - '1 years'::interval) AS cap1_avg_earnings,
avg(book) FILTER (WHERE date >= rec.date - '1 years'::interval) AS cap1_avg_book,
avg(sales) FILTER (WHERE date >= rec.date - '1 years'::interval) AS cap1_avg_sales,
avg(cashflow) FILTER (WHERE date >= rec.date - '1 years'::interval) AS cap1_avg_cashflow,
avg(dividends) FILTER (WHERE date >= rec.date - '1 years'::interval) AS cap1_avg_dividends,
avg(earnings) FILTER (WHERE date >= rec.date - '2 years'::interval) AS cap2_avg_earnings,
avg(book) FILTER (WHERE date >= rec.date - '2 years'::interval) AS cap2_avg_book,
avg(sales) FILTER (WHERE date >= rec.date - '2 years'::interval) AS cap2_avg_sales,
avg(cashflow) FILTER (WHERE date >= rec.date - '2 years'::interval) AS cap2_avg_cashflow,
avg(dividends) FILTER (WHERE date >= rec.date - '2 years'::interval) AS cap2_avg_dividends,
avg(earnings) FILTER (WHERE date >= rec.date - '3 years'::interval) AS cap3_avg_earnings,
avg(book) FILTER (WHERE date >= rec.date - '3 years'::interval) AS cap3_avg_book,
avg(sales) FILTER (WHERE date >= rec.date - '3 years'::interval) AS cap3_avg_sales,
avg(cashflow) FILTER (WHERE date >= rec.date - '3 years'::interval) AS cap3_avg_cashflow,
avg(dividends) FILTER (WHERE date >= rec.date - '3 years'::interval) AS cap3_avg_dividends,
avg(earnings) FILTER (WHERE date >= rec.date - '4 years'::interval) AS cap4_avg_earnings,
avg(book) FILTER (WHERE date >= rec.date - '4 years'::interval) AS cap4_avg_book,
avg(sales) FILTER (WHERE date >= rec.date - '4 years'::interval) AS cap4_avg_sales,
avg(cashflow) FILTER (WHERE date >= rec.date - '4 years'::interval) AS cap4_avg_cashflow,
avg(dividends) FILTER (WHERE date >= rec.date - '4 years'::interval) AS cap4_avg_dividends,
avg(earnings) FILTER (WHERE date >= rec.date - '5 years'::interval) AS cap5_avg_earnings,
avg(book) FILTER (WHERE date >= rec.date - '5 years'::interval) AS cap5_avg_book,
avg(sales) FILTER (WHERE date >= rec.date - '5 years'::interval) AS cap5_avg_sales,
avg(cashflow) FILTER (WHERE date >= rec.date - '5 years'::interval) AS cap5_avg_cashflow,
avg(dividends) FILTER (WHERE date >= rec.date - '5 years'::interval) AS cap5_avg_dividends,
avg(earnings) FILTER (WHERE date >= rec.date - '6 years'::interval) AS cap6_avg_earnings,
avg(book) FILTER (WHERE date >= rec.date - '6 years'::interval) AS cap6_avg_book,
avg(sales) FILTER (WHERE date >= rec.date - '6 years'::interval) AS cap6_avg_sales,
avg(cashflow) FILTER (WHERE date >= rec.date - '6 years'::interval) AS cap6_avg_cashflow,
avg(dividends) FILTER (WHERE date >= rec.date - '6 years'::interval) AS cap6_avg_dividends,
avg(earnings) FILTER (WHERE date >= rec.date - '7 years'::interval) AS cap7_avg_earnings,
avg(book) FILTER (WHERE date >= rec.date - '7 years'::interval) AS cap7_avg_book,
avg(sales) FILTER (WHERE date >= rec.date - '7 years'::interval) AS cap7_avg_sales,
avg(cashflow) FILTER (WHERE date >= rec.date - '7 years'::interval) AS cap7_avg_cashflow,
avg(dividends) FILTER (WHERE date >= rec.date - '7 years'::interval) AS cap7_avg_dividends,
avg(earnings) FILTER (WHERE date >= rec.date - '8 years'::interval) AS cap8_avg_earnings,
avg(book) FILTER (WHERE date >= rec.date - '8 years'::interval) AS cap8_avg_book,
avg(sales) FILTER (WHERE date >= rec.date - '8 years'::interval) AS cap8_avg_sales,
avg(cashflow) FILTER (WHERE date >= rec.date - '8 years'::interval) AS cap8_avg_cashflow,
avg(dividends) FILTER (WHERE date >= rec.date - '8 years'::interval) AS cap8_avg_dividends,
avg(earnings) FILTER (WHERE date >= rec.date - '9 years'::interval) AS cap9_avg_earnings,
avg(book) FILTER (WHERE date >= rec.date - '9 years'::interval) AS cap9_avg_book,
avg(sales) FILTER (WHERE date >= rec.date - '9 years'::interval) AS cap9_avg_sales,
avg(cashflow) FILTER (WHERE date >= rec.date - '9 years'::interval) AS cap9_avg_cashflow,
avg(dividends) FILTER (WHERE date >= rec.date - '9 years'::interval) AS cap9_avg_dividends,
avg(earnings) AS cap10_avg_earnings,
avg(book) AS cap10_avg_book,
avg(sales) AS cap10_avg_sales,
avg(cashflow) AS cap10_avg_cashflow,
avg(dividends) AS cap10_avg_dividends
FROM bloomberg.security_data DATA
WHERE security_id = rec.security_id
AND date >= rec.date - '10 years'::interval
AND date <= rec.date
) ru;
任何有关如何加快速度的想法都会非常受欢迎，因为我是PostgreSQL的新手。
以下是供参考的数据库设置：
CREATE SCHEMA bloomberg;
CREATE TABLE bloomberg.securities (
security_id character varying(45) PRIMARY KEY,
name_short character varying(45) NOT NULL,
name character varying(45) NOT NULL,
name_security character varying(45) NOT NULL
);
CREATE TABLE bloomberg.security_data (
record_id bigserial PRIMARY KEY,
date date NOT NULL,
security_id character varying(45) NOT NULL,
price double precision,
total_return double precision,
earnings double precision,
book double precision,
sales double precision,
cashflow double precision,
dividends double precision,
CONSTRAINT security_id FOREIGN KEY (security_id)
REFERENCES bloomberg.securities (security_id) MATCH SIMPLE
ON UPDATE CASCADE
ON DELETE CASCADE
);
CREATE INDEX security_data_data on bloomberg.security_data (date);
CREATE INDEX security_data_security_id on bloomberg.security_data (security_id);
答案 0 :(得分：1)
这应该是具有LATERAL子查询的更快的变体。未经测试。
SELECT s.record_id, s.security_id, s.date
, s.price / l.pmax AS price_to_peak_earnings
, s.price / l.pmin AS price_to_minimum_earnings
-- , ...
, s.price / l.cape1 AS cape1
, s.price / l.cape2 AS cape2
-- , ...
, s.price / l.cape10 AS cape10
, s.price / l.capb1 AS capb1
, s.price / l.capb2 AS capb2
-- , ...
, s.price / l.capb10 AS capb10
-- , ...
FROM (
SELECT *
, (date - interval '1 y')::date AS date1
, (date - interval '2 y')::date AS date2
-- ...
, (date - interval '10 y')::date AS date10
FROM (
SELECT *, min(date) OVER (PARTITION BY security_id) AS min_date
FROM security_data
) s1
) s
LEFT JOIN LATERAL (
SELECT CASE WHEN s.date10 >= s.min_date THEN NULLIF(max(earnings) , 0) END AS pmax
, CASE WHEN s.date10 >= s.min_date THEN NULLIF(min(earnings) , 0) END AS pmin
-- ...
, NULLIF(avg(earnings) FILTER (WHERE date >= s.date1), 0) AS cape1 -- no case
, CASE WHEN s.date2 >= s.min_date THEN NULLIF(avg(earnings) FILTER (WHERE date >= s.date2), 0) END AS cape2
-- ...
, CASE WHEN s.date10 >= s.min_date THEN NULLIF(avg(earnings) , 0) END AS cape10 -- no filter
, NULLIF(avg(book) FILTER (WHERE date >= s.date1), 0) AS capb1
, CASE WHEN s.date2 >= s.min_date THEN NULLIF(avg(book) FILTER (WHERE date >= s.date2), 0) END AS capb2
-- ...
, CASE WHEN s.date10 >= s.min_date THEN NULLIF(avg(book) , 0) END AS capb10
-- ...
FROM security_data
WHERE security_id = s.security_id
AND date >= s.date10
AND date < s.date
) l ON s.date1 >= s.min_date -- no computations if < 1 year of trailing data
ORDER BY s.security_id, s.date;
它仍然不会非常快，因为每一行都需要多个单独的聚合。这里的瓶颈将是CPU。
另请参阅后续替代方法（JOIN生成日历+窗口函数）：