小编mhv*_*vis的帖子

我有下表。它存储为 TimescaleDB 超表。数据速率为每秒 1 行。

CREATE TABLE electricity_data
(
    "time" timestamptz NOT NULL,
    meter_id integer REFERENCES meters NOT NULL,
    import_low double precision,
    import_normal double precision,
    export_low double precision,
    export_normal double precision,
    PRIMARY KEY ("time", meter_id)
)

我想获取一段时间内给定时间间隔内的最新行。例如上一年每个月的最新记录。以下查询可以工作，但速度很慢：

EXPLAIN ANALYZE
SELECT
DISTINCT ON (bucket)
time_bucket('1 month', "time", 'Europe/Amsterdam') AS bucket,
import_low,
import_normal,
export_low,
export_normal
FROM electricity_data
WHERE meter_id = 1
AND "time" BETWEEN '2022-01-01T00:00:00 Europe/Amsterdam' AND '2023-01-01T00:00:00 Europe/Amsterdam'
ORDER BY bucket DESC

Unique  (cost=0.42..542380.99 rows=200 width=40) (actual time=3654.263..59130.398 rows=12 loops=1)
  -> …