Postgres SQL 大查询速度慢 table (AWS RDS)

Question

目前table的最小行数为3000万，而且还在增长，每当尝试做SELECT查询时，都需要非常长的时间。在提高数据库性能之前需要优化什么查询？

POSTGRES 12 on AWS RDS db.t3.small, with 20GB storage

**Message Table**

id (bigint) -> pk
meta (jsonb)
snapshot_ts (integer) -> epoch timestamp
value (character varying 100)
type (character varying 50)
created (timestamp with timezone)
last_modified (timestamp with timezone)
attribute_id (bigint) -> Foreign Key
company_id (bigint) -> Foreign Key
project_id (bigint) -> Foreign Key
device_id (bigint) -> Foreign Key


EXPLAIN (analyze,buffers) SELECT COUNT(*) FROM public.message
WHERE company_id=446 AND project_id=52 AND snapshot_ts>=1637568000.0 AND snapshot_ts<=1637654399.0 AND attribute_id=458

->Aggregate  (cost=399804.26..399804.27 rows=1 width=8) (actual time=65150.696..65150.697 rows=1 loops=1)
  Buffers: shared hit=170 read=115437 dirtied=167
  I/O Timings: read=64396.424
  ->  Index Scan using message_attribute_id_6578b282 on message  (cost=0.56..399803.23 rows=411 width=0) (actual time=57752.297..65147.391 rows=8656 loops=1)
        Index Cond: (attribute_id = 458)
        Filter: ((company_id = 446) AND (project_id = 52) AND ((snapshot_ts)::numeric >= 1637568000.0) AND ((snapshot_ts)::numeric <= 1637654399.0))
        Rows Removed by Filter: 106703
        Buffers: shared hit=170 read=115437 dirtied=167
        I/O Timings: read=64396.424
Planning Time: 0.779 ms
Execution Time: 65150.730 ms

**Indexes**
indexname                       | indexdef
message_attribute_id_6578b282   | CREATE INDEX message_attribute_id_6578b282 ON public.message USING btree (attribute_id)
message_company_id_cef5ed5f     | CREATE INDEX message_company_id_cef5ed5f ON public.message USING btree (company_id)
message_device_id_b4da2571      | CREATE INDEX message_device_id_b4da2571 ON public.message USING btree (device_id)
message_pkey                    | CREATE UNIQUE INDEX message_pkey ON public.message USING btree (id)
message_project_id_7ba6787d     | CREATE INDEX message_project_id_7ba6787d ON public.message USING btree (project_id)

Answer 1

考虑具体查询：

SELECT COUNT(*)
FROM public.message
WHERE company_id=446 
  AND project_id=52 
  AND snapshot_ts>=1637568000.0 AND snapshot_ts<=1637654399.0 
  AND attribute_id=458

以下索引具有极大提高性能的潜力：

create index ix1 on public.message (
  company_id, project_id, attribute_id, snapshot_ts
);

但是，请记住，在 3000 万行上创建索引 table 可能需要一些时间。

Postgres SQL 大查询速度慢 table (AWS RDS)

Postgres SQL query slow with large table (AWS RDS)

sql

postgresql

amazon-rds

postgresql-12