Fix FOR bug, also fix bench to compile

bench-vortex/src/bin/compress.rs

@@ -4,35 +4,35 @@ use std::path::PathBuf;
 use bench_vortex::data_downloads::BenchmarkDataset;
 use bench_vortex::public_bi_data::BenchmarkDatasets::PBI;
 use bench_vortex::public_bi_data::PBIDataset;
-use bench_vortex::reader::{open_vortex, rewrite_parquet_as_vortex};
+use bench_vortex::reader::{open_vortex_async, rewrite_parquet_as_vortex};
 use bench_vortex::taxi_data::taxi_data_parquet;
 use bench_vortex::{setup_logger, IdempotentPath};
-use futures::executor::block_on;
 use log::{info, LevelFilter};
 use tokio::fs::File;
+use vortex_error::VortexResult;
 
-pub fn main() {
+#[tokio::main]
+pub async fn main() {
     setup_logger(LevelFilter::Info);
     // compress_pbi(PBIDataset::Medicare1);
-    compress_taxi();
+    compress_taxi().await.unwrap();
 }
 
-fn compress_taxi() {
+async fn compress_taxi() -> VortexResult<()> {
     let path: PathBuf = "taxi_data.vortex".to_data_path();
-    block_on(async {
-        let output_file = File::create(&path).await?;
-        rewrite_parquet_as_vortex(taxi_data_parquet(), output_file).await
-    })
-    .unwrap();
+    let output_file = File::create(&path).await?;
+    rewrite_parquet_as_vortex(taxi_data_parquet(), output_file).await?;
 
-    let taxi_vortex = open_vortex(&path).unwrap();
+    let taxi_vortex = open_vortex_async(&path).await?;
     info!("{}", taxi_vortex.tree_display());
 
     let pq_size = taxi_data_parquet().metadata().unwrap().size();
     let vx_size = taxi_vortex.nbytes();
 
     info!("Parquet size: {}, Vortex size: {}", pq_size, vx_size);
     info!("Compression ratio: {}", vx_size as f32 / pq_size as f32);
+
+    Ok(())
 }
 
 #[allow(dead_code)]

bench-vortex/src/reader.rs

@@ -47,6 +47,17 @@ pub fn open_vortex(path: &Path) -> VortexResult<Array> {
         .map(|a| a.into_array())
 }
 
+pub async fn open_vortex_async(path: &Path) -> VortexResult<Array> {
+    let file = tokio::fs::File::open(path).await.unwrap();
+    let mut msgs = MessageReader::try_new(TokioAdapter(file)).await.unwrap();
+    msgs.array_stream_from_messages(&CTX)
+        .await
+        .unwrap()
+        .collect_chunked()
+        .await
+        .map(|a| a.into_array())
+}
+
 pub async fn rewrite_parquet_as_vortex<W: VortexWrite>(
     parquet_path: PathBuf,
     write: W,

vortex-fastlanes/src/for/compress.rs

@@ -7,6 +7,7 @@ use vortex::stats::{ArrayStatistics, Stat};
 use vortex::{Array, ArrayDType, ArrayTrait, IntoArray};
 use vortex_dtype::{match_each_integer_ptype, NativePType, PType};
 use vortex_error::{vortex_err, VortexResult};
+use vortex_scalar::Scalar;
 
 use crate::{FoRArray, FoREncoding};
 
@@ -53,7 +54,7 @@ impl EncodingCompression for FoREncoding {
 
         let child = match_each_integer_ptype!(parray.ptype(), |$T| {
             if shift == <$T>::PTYPE.bit_width() as u8 {
-                ConstantArray::new($T::default(), parray.len()).into_array()
+                ConstantArray::new(Scalar::zero::<$T>(parray.dtype().nullability()), parray.len()).into_array()
             } else {
                 compress_primitive::<$T>(parray, shift, $T::try_from(&min)?).into_array()
             }