alamb commented on code in PR #479: URL: https://github.com/apache/arrow-site/pull/479#discussion_r1509481390
########## _posts/2024-02-27-comet-donation.md: ########## @@ -0,0 +1,106 @@ +--- +layout: post +title: "Announcing Apache Arrow DataFusion Comet" +date: "2024-02-27 00:00:00" +author: pmc +categories: [release] +--- +<!-- +{% comment %} +Licensed to the Apache Software Foundation (ASF) under one or more +contributor license agreements. See the NOTICE file distributed with +this work for additional information regarding copyright ownership. +The ASF licenses this file to you under the Apache License, Version 2.0 +(the "License"); you may not use this file except in compliance with +the License. You may obtain a copy of the License at + +http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +{% endcomment %} +--> + +# Introduction +The Apache Arrow PMC is pleased to announce the donation of the [Comet project], +a native Spark SQL Accelerator built on [Apache Arrow DataFusion]. + +Comet is an Apache Spark plugin that uses Apache Arrow DataFusion to +accelerate Spark workloads. It is designed as a drop-in +replacement for Spark's JVM based SQL execution engine and offers significant +performance improvements for some workloads as shown below. + +```text + ┌─────────────────────────────────────────────────────────────────┐ + │ │ + │ ┌──────────┐ ┌────────────┐ ┌────────────┐ ┌────────────┐ │ + │ │ SQL │ │ Cluster │ │ DAG/Task │ ... │ Executor │ │ + │ │ Planner │ │ Manager │ │ Scheduler │ │ │ │ + │ └──────────┘ └────────────┘ └────────────┘ └────────────┘ │ + │ │ │ + └─────────────────────────────────────────────────────────────────┘ + Spark (JVM Based) │ + ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ + + │ + ▼ + ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓ +Comet Execution ┃ ┃ +Engine ┃ ┌─────────────────────────┐ ┃ +(Native Code) ┃ │ Apache Arrow DataFusion │ ┃ + ┃ └─────────────────────────┘ ┃ + ┃ ┃ + ┃ ┌─────────────────────────┐ ┃ + ┃ │ Spark Compatible │ ┃ + ┃ │ Expressions/Operators │ ┃ + ┃ └─────────────────────────┘ ┃ + ┃ ┃ + ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛ +``` + +**Figure 1**: With Comet, users interact with the same Spark ecosystem, tools +and APIs such as Spark SQL. Queries still run through Spark's mature and feature +rich query optimizer and planner. However, the execution is delegated to Comet, +which is significantly faster and more resource efficient than the JVM based +implementation. + +[Rust]: https://www.rust-lang.org/ + +# Background + +Comet is one of a growing class of projects that aim to accelerate Spark using +native columnar engines such as the proprietary [Databricks Photon Engine] and +the open source [Gluten project] and [Spark RAPIDS]. Review Comment: Thank you @SChakravorti21 for this suggestion. I agree such background would help -- maybe some of the other reviewers (some of whom are spark committers I believe) can offer more specifics and how this relates to mainline spark. The [Velox Paper](https://vldb.org/pvldb/vol15/p3372-pedreira.pdf) basically says the JVM implementation of spark is slow so native columnar execution is better, but I don't recall it delving into any more detail -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org