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# Ballista Quickstart

A simple way to start a local cluster for testing purposes is to use cargo to build the project and then run the scheduler and executor binaries directly.

Project Requirements:

- [Rust](https://www.rust-lang.org/tools/install)
- [Protobuf Compiler](https://protobuf.dev/downloads/)

## Build the project

From the root of the project, build release binaries.

```shell
cargo build --release
```

Start a Ballista scheduler process in a new terminal session.

```shell
RUST_LOG=info ./target/release/ballista-scheduler
```

Start one or more Ballista executor processes in new terminal sessions. When starting more than one
executor, a unique port number must be specified for each executor.

```shell
RUST_LOG=info ./target/release/ballista-executor -c 2 -p 50051 --bind-grpc-port 50052

RUST_LOG=info ./target/release/ballista-executor -c 2 -p 50053 --bind-grpc-port 50054
```

## Running the examples

The examples can be run using the `cargo run --bin` syntax. Open a new terminal session and run the following commands.

### Distributed SQL Example

```bash
cd examples
cargo run --release --example remote-sql
```

#### Source code for distributed SQL example

```rust
use ballista::prelude::*;
use ballista_examples::test_util;
use datafusion::{
    execution::SessionStateBuilder,
    prelude::{CsvReadOptions, SessionConfig, SessionContext},
};

/// This example demonstrates executing a simple query against an Arrow data source (CSV) and
/// fetching results, using SQL
#[tokio::main]
async fn main() -> Result<()> {
    let config = SessionConfig::new_with_ballista()
        .with_target_partitions(4)
        .with_ballista_job_name("Remote SQL Example");

    let state = SessionStateBuilder::new()
        .with_config(config)
        .with_default_features()
        .build();

    let ctx = SessionContext::remote_with_state("df://localhost:50050", state).await?;

    let test_data = test_util::examples_test_data();

    ctx.register_csv(
        "test",
        &format!("{test_data}/aggregate_test_100.csv"),
        CsvReadOptions::new(),
    )
    .await?;

    let df = ctx
        .sql(
            "SELECT c1, MIN(c12), MAX(c12) \
        FROM test \
        WHERE c11 > 0.1 AND c11 < 0.9 \
        GROUP BY c1",
        )
        .await?;

    df.show().await?;

    Ok(())
}
```

### Distributed DataFrame Example

```bash
cd examples
cargo run --release --example remote-dataframe
```

#### Source code for distributed DataFrame example

```rust
use ballista::prelude::*;
use ballista_examples::test_util;
use datafusion::{
    prelude::{col, lit, ParquetReadOptions, SessionContext},
};

#[tokio::main]
async fn main() -> Result<()> {
    // creating SessionContext with default settings
    let ctx = SessionContext::remote("df://localhost:50050").await?;

    let test_data = test_util::examples_test_data();
    let filename = format!("{test_data}/alltypes_plain.parquet");

    let df = ctx
        .read_parquet(filename, ParquetReadOptions::default())
        .await?
        .select_columns(&["id", "bool_col", "timestamp_col"])?
        .filter(col("id").gt(lit(1)))?;

    df.show().await?;

    Ok(())
}
```