4paradigm / 4paradigm/OpenMLDB

feat: support distributed query on BatchMode under some restrictions

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#318 0 comments 0 reactions 1 assignee Claimed by @jingchen2222 View on GitHub
enhancement
Dominant language
C++
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Forks
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Avg merge
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Merged PRs (30d)
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Description

**Is your feature request related to a problem? Please describe.**

Users can be frustrated when distributed batch queries aren't suported currently.
We are considering support batch queried under the distributed environment with some specific restrictions.
- simple query can be supported because the queried rows are independent.
- complex query with aggregation can be supported if the aggregation data has been are partitioned by index.
- aggregation query on data group by index
- aggregation query on data filter by index
- aggregation query on window filter by index

In this issue, we are going to support aggregation query on data group/filter by partition key.

**Describe the solution you'd like**

Before we deep into the implementation of distributed batch queries, we have to deal with some related issues below:
- Support general aggeration like, `SUM`, `MIN`, `MAX` etc, on the whole table #219
- Optimize SQL plan when the queried table is filtered and grouped by the same key/expression #317

**Describe alternatives you've considered**
A clear and concise description of any alternative solutions or features you've considered.

**Additional context**
Add any other context or screenshots about the feature request here.

Contributor guide

Open the contributing guide

Research direction

The issue describes adding distributed batch query support for aggregation queries filtered/grouped by partition key. Start by reviewing the existing batch query and distributed execution code. Look at related issues #219 and #317 for prerequisite work. Understand the table partitioning and aggregation execution paths. A newcomer would need to understand the distributed query engine and SQL planner.

Written by the indexing model from the issue text.

Assessment

Tech stack
sql
Domain
databases, distributed-systems, machine-learning
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
20/100

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