taosdata/TDengine

group by times out when querying large amounts of data from a single table

Open

#28,744 opened on Nov 12, 2024

View on GitHub
 (2 comments) (0 reactions) (1 assignee)C (5,002 forks)batch import
help wanted

Repository metrics

Stars
 (24,849 stars)
PR merge metrics
 (Avg merge 1d 1h) (4 merged PRs in 30d)

Description

问题描述：单张主表1.7亿左右数据，针对单个字段使用group by分组查询，结合last_row获取最新值，查询出现超时；如果加上时间（ts）过滤条件，1月查询耗时1.3秒左右； 服务器资源：内存、cpu很充裕 docker镜像版本3.3.3.0

Contributor guide

Research direction
Examine the query execution plan for the group by and last row on a large table; check server configuration and resource limits; test with different indexing or partitioning strategies.
Tech stack
c
Domain
database
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
SQLDatabase fundamentals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50