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Posted to github@arrow.apache.org by "waynexia (via GitHub)" <gi...@apache.org> on 2023/04/12 07:56:54 UTC

[GitHub] [arrow-datafusion] waynexia commented on a diff in pull request #5962: [DOCS]: consolidate doc site content simplify navbar

waynexia commented on code in PR #5962:
URL: https://github.com/apache/arrow-datafusion/pull/5962#discussion_r1163748404


##########
docs/source/contributor-guide/architecture.md:
##########
@@ -20,7 +20,8 @@
 # Architecture
 
 DataFusion's code structure and organization is described in the
-[Crate Documentation], to keep it as close to the source as
-possible.
+[crates.io documentation], to keep it as close to the source as
+possible. You can find the most up to date version in the [source code].

Review Comment:
   What do you think about hosting the latest document generated from the source code on github pages (or other static page hoster)? Like [greptimedb.rs](https://greptimedb.rs) which is generated from https://github.com/GreptimeTeam/greptimedb/deployments/activity_log?environment=github-pages



##########
docs/source/user-guide/example-usage.md:
##########
@@ -141,3 +141,112 @@ async fn main() -> datafusion::error::Result<()> {
 | 1 | 2      |
 +---+--------+
 ```
+
+# Using DataFusion as a library
+
+## Create a new project
+
+```shell
+cargo new hello_datafusion
+```
+
+```shell
+$ cd hello_datafusion
+$ tree .
+.
+├── Cargo.toml
+└── src
+    └── main.rs
+
+1 directory, 2 files
+```
+
+## Default Configuration
+
+DataFusion is [published on crates.io](https://crates.io/crates/datafusion), and is [well documented on docs.rs](https://docs.rs/datafusion/).
+
+To get started, add the following to your `Cargo.toml` file:
+
+```toml
+[dependencies]
+datafusion = "11.0"
+```
+
+## Create a main function
+
+Update the main.rs file with your first datafusion application based on [Example usage](https://arrow.apache.org/datafusion/user-guide/example-usage.html)
+
+```rust
+use datafusion::prelude::*;
+
+#[tokio::main]
+async fn main() -> datafusion::error::Result<()> {
+  // register the table
+  let ctx = SessionContext::new();
+  ctx.register_csv("test", "<PATH_TO_YOUR_CSV_FILE>", CsvReadOptions::new()).await?;
+
+  // create a plan to run a SQL query
+  let df = ctx.sql("SELECT * FROM test").await?;
+
+  // execute and print results
+  df.show().await?;
+  Ok(())
+}
+```
+
+## Extensibility
+
+DataFusion is designed to be extensible at all points. To that end, you can provide your own custom:
+
+- [x] User Defined Functions (UDFs)
+- [x] User Defined Aggregate Functions (UDAFs)
+- [x] User Defined Table Source (`TableProvider`) for tables
+- [x] User Defined `Optimizer` passes (plan rewrites)
+- [x] User Defined `LogicalPlan` nodes
+- [x] User Defined `ExecutionPlan` nodes
+
+## Rust Version Compatibility
+
+This crate is tested with the latest stable version of Rust. We do not currently test against other, older versions of the Rust compiler.
+
+## Optimized Configuration
+
+For an optimized build several steps are required. First, use the below in your `Cargo.toml`. It is
+worth noting that using the settings in the `[profile.release]` section will significantly increase the build time.
+
+```toml
+[dependencies]
+datafusion = { version = "11.0" , features = ["simd"]}

Review Comment:
   This is also outdated. Wondering if there are someway to render code / file from github? So we needn't update this file every time but rather render our example codes. I find [this](https://github.blog/2017-08-15-introducing-embedded-code-snippets/) but it looks only works inside github.



##########
docs/source/user-guide/faq.md:
##########
@@ -29,3 +29,37 @@ model and computational kernels. It is designed to run within a single process,
 for parallel query execution.
 
 [Ballista](https://github.com/apache/arrow-ballista) is a distributed compute platform built on DataFusion.
+
+# How does DataFusion Compare with `XYZ`?
+
+When compared to similar systems, DataFusion typically is:
+
+1. Targeted at developers, rather than end users / data scientists.
+2. Designed to be embedded, rather than a complete file based SQL system.
+3. Governed by the [Apache Software Foundation](https://www.apache.org/) process, rather than a single company or individual.
+4. Implemented in `Rust`, rather than `C/C++`
+
+Here is a comparison with similar projects that may help understand
+when DataFusion might be be suitable and unsuitable for your needs:
+
+- [DuckDB](http://www.duckdb.org) is an open source, in process analytic database.
+  Like DataFusion, it supports very fast execution, both from its custom file format
+  and directly from parquet files. Unlike DataFusion, it is written in C/C++ and it
+  is primarily used directly by users as a serverless database and query system rather
+  than as a library for building such database systems.
+
+- [Polars](http://pola.rs): Polars is one of the fastest DataFrame
+  libraries at the time of writing. Like DataFusion, it is also
+  written in Rust and uses the Apache Arrow memory model, but unlike
+  DataFusion it does not provide SQL nor as many extension points.
+
+- [Facebook Velox](https://engineering.fb.com/2022/08/31/open-source/velox/)
+  is an execution engine. Like DataFusion, Velox aims to
+  provide a reusable foundation for building database-like systems. Unlike DataFusion,
+  it is written in C/C++ and does not include a SQL frontend or planning /optimization

Review Comment:
   ```suggestion
     it is written in C/C++ and does not include a SQL frontend or planning / optimization
   ```



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