Write Multiple Parquet Files in Parallel#7483
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alamb merged 1 commit intoapache:mainfrom Sep 7, 2023
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Thanks @devinjdangelo
My local tests suggest this goes slightly faster:
This branch: 20.310647042s
main: 57.579146358s
I tested this with the following setup:
cargo run --release[package]
name = "perf_test"
version = "0.1.0"
edition = "2021"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
env_logger = "0.10.0"
parquet = "46.0.0"
serde = "1.0.163"
serde_json = "1.0.96"
datafusion = { path = '/Users/alamb/Software/arrow-datafusion/datafusion/core', default-features = false }
object_store = "0.7.0"
tokio = "1.0"
chrono = "0.4.26"
url = "2.4.1"use chrono;
use datafusion::{
dataframe::DataFrameWriteOptions, datasource::listing::ListingTableInsertMode,
error::DataFusionError, prelude::*,
};
use object_store::local::LocalFileSystem;
use std::{sync::Arc, time::Instant};
use url::Url;
const FILENAME: &str =
"/Users/alamb/Software/arrow-datafusion/benchmarks/data/tpch_sf10/lineitem/part-0.parquet";
#[tokio::main]
async fn main() -> Result<(), DataFusionError> {
let _ctx = SessionContext::new();
let local = Arc::new(LocalFileSystem::new());
let local_url = Url::parse("file://local").unwrap();
_ctx.runtime_env().register_object_store(&local_url, local);
let _read_options = ParquetReadOptions {
file_extension: ".parquet",
table_partition_cols: vec![],
parquet_pruning: None,
skip_metadata: None,
schema: None,
file_sort_order: vec![],
insert_mode: ListingTableInsertMode::AppendNewFiles,
};
let df = _ctx
.read_parquet(FILENAME, _read_options)
.await
.unwrap()
.repartition(Partitioning::RoundRobinBatch(16))
.unwrap();
let start = Instant::now();
println!("datafusion start -> {:?}", chrono::offset::Local::now());
let props = None;
let write_options = DataFrameWriteOptions::new().with_single_file_output(false);
df.write_parquet("file:///tmp/test_out/", write_options, props)
.await?;
let elapsed = Instant::now() - start;
println!(
"datafusion end -> {:?} {elapsed:?}",
chrono::offset::Local::now()
);
Ok(())
}
Contributor
|
Note that I had to explicitly set the distribution |
Contributor
|
Thanks again @devinjdangelo |
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Which issue does this PR close?
Closes #7079
Rationale for this change
When writing out multiple partitions to multiple parquet files, we can speed up the operation by writing all parquet files in parallel on multiple cpu cores.
Parallelizing the serialization of a single parquet file (similar to as done for csv/json in #7452) is more complex and will need upstream changes in arrow-rs. There is already an issue open for this here apache/arrow-rs#1718.
What changes are included in this PR?
Spawn a tokio task for each parquet file being written.
Are these changes tested?
Yes by existing tests.
Are there any user-facing changes?
No other than better write performance when writing multiple parquet files on a system with multiple cpu cores.