Start on binary copy rewrite

Author: sfackler

Cargo.toml

@@ -9,6 +9,7 @@ members = [
     "postgres-protocol",
     "postgres-types",
     "tokio-postgres",
+    "tokio-postgres-binary-copy",
 ]
 
 [profile.release]

tokio-postgres-binary-copy/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "tokio-postgres-binary-copy"
+version = "0.1.0"
+authors = ["Steven Fackler <sfackler@gmail.com>"]
+edition = "2018"
+
+[dependencies]
+bytes = "0.4"
+futures-preview = "=0.3.0-alpha.19"
+parking_lot = "0.9"
+pin-project-lite = "0.1"
+tokio-postgres = { version = "=0.5.0-alpha.1", default-features = false, path = "../tokio-postgres" }
+
+[dev-dependencies]
+tokio = "=0.2.0-alpha.6"
+tokio-postgres = { version = "=0.5.0-alpha.1", path = "../tokio-postgres" }
+

tokio-postgres-binary-copy/src/lib.rs

@@ -0,0 +1,123 @@
+use bytes::{BigEndian, BufMut, ByteOrder, Bytes, BytesMut};
+use futures::{future, Stream};
+use parking_lot::Mutex;
+use pin_project_lite::pin_project;
+use std::convert::TryFrom;
+use std::error::Error;
+use std::future::Future;
+use std::pin::Pin;
+use std::sync::Arc;
+use std::task::{Context, Poll};
+use tokio_postgres::types::{IsNull, ToSql, Type};
+
+#[cfg(test)]
+mod test;
+
+const BLOCK_SIZE: usize = 4096;
+
+pin_project! {
+    pub struct BinaryCopyStream<F> {
+        #[pin]
+        future: F,
+        buf: Arc<Mutex<BytesMut>>,
+        done: bool,
+    }
+}
+
+impl<F> BinaryCopyStream<F>
+where
+    F: Future<Output = Result<(), Box<dyn Error + Sync + Send>>>,
+{
+    pub fn new<M>(types: &[Type], write_values: M) -> BinaryCopyStream<F>
+    where
+        M: FnOnce(BinaryCopyWriter) -> F,
+    {
+        let mut buf = BytesMut::new();
+        buf.reserve(11 + 4 + 4);
+        buf.put_slice(b"PGCOPY\n\xff\r\n\0"); // magic
+        buf.put_i32_be(0); // flags
+        buf.put_i32_be(0); // header extension
+
+        let buf = Arc::new(Mutex::new(buf));
+        let writer = BinaryCopyWriter {
+            buf: buf.clone(),
+            types: types.to_vec(),
+            idx: 0,
+        };
+
+        BinaryCopyStream {
+            future: write_values(writer),
+            buf,
+            done: false,
+        }
+    }
+}
+
+impl<F> Stream for BinaryCopyStream<F>
+where
+    F: Future<Output = Result<(), Box<dyn Error + Sync + Send>>>,
+{
+    type Item = Result<Bytes, Box<dyn Error + Sync + Send>>;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        let this = self.project();
+
+        if *this.done {
+            return Poll::Ready(None);
+        }
+
+        *this.done = this.future.poll(cx)?.is_ready();
+
+        let mut buf = this.buf.lock();
+        if *this.done {
+            buf.reserve(2);
+            buf.put_i16_be(-1);
+            Poll::Ready(Some(Ok(buf.take().freeze())))
+        } else if buf.len() > BLOCK_SIZE {
+            Poll::Ready(Some(Ok(buf.take().freeze())))
+        } else {
+            Poll::Pending
+        }
+    }
+}
+
+// FIXME this should really just take a reference to the buffer, but that requires HKT :(
+pub struct BinaryCopyWriter {
+    buf: Arc<Mutex<BytesMut>>,
+    types: Vec<Type>,
+    idx: usize,
+}
+
+impl BinaryCopyWriter {
+    pub async fn write(
+        &mut self,
+        value: &(dyn ToSql + Send),
+    ) -> Result<(), Box<dyn Error + Sync + Send>> {
+        future::poll_fn(|_| {
+            if self.buf.lock().len() > BLOCK_SIZE {
+                Poll::Pending
+            } else {
+                Poll::Ready(())
+            }
+        })
+        .await;
+
+        let mut buf = self.buf.lock();
+        if self.idx == 0 {
+            buf.reserve(2);
+            buf.put_i16_be(self.types.len() as i16);
+        }
+        let idx = buf.len();
+        buf.reserve(4);
+        buf.put_i32_be(0);
+        let len = match value.to_sql_checked(&self.types[self.idx], &mut buf)? {
+            IsNull::Yes => -1,
+            IsNull::No => i32::try_from(buf.len() - idx - 4)?,
+        };
+        BigEndian::write_i32(&mut buf[idx..], len);
+
+        self.idx = (self.idx + 1) % self.types.len();
+
+        Ok(())
+    }
+}

tokio-postgres-binary-copy/src/test.rs

@@ -0,0 +1,101 @@
+use crate::BinaryCopyStream;
+use tokio_postgres::types::Type;
+use tokio_postgres::{Client, NoTls};
+
+async fn connect() -> Client {
+    let (client, connection) =
+        tokio_postgres::connect("host=localhost port=5433 user=postgres", NoTls)
+            .await
+            .unwrap();
+    tokio::spawn(async {
+        connection.await.unwrap();
+    });
+    client
+}
+
+#[tokio::test]
+async fn write_basic() {
+    let client = connect().await;
+
+    client
+        .batch_execute("CREATE TEMPORARY TABLE foo (id INT, bar TEXT)")
+        .await
+        .unwrap();
+
+    let stream = BinaryCopyStream::new(&[Type::INT4, Type::TEXT], |mut w| {
+        async move {
+            w.write(&1i32).await?;
+            w.write(&"foobar").await?;
+
+            w.write(&2i32).await?;
+            w.write(&None::<&str>).await?;
+
+            Ok(())
+        }
+    });
+
+    client
+        .copy_in("COPY foo (id, bar) FROM STDIN BINARY", &[], stream)
+        .await
+        .unwrap();
+
+    let rows = client.query("SELECT id, bar FROM foo ORDER BY id", &[]).await.unwrap();
+    assert_eq!(rows.len(), 2);
+    assert_eq!(rows[0].get::<_, i32>(0), 1);
+    assert_eq!(rows[0].get::<_, Option<&str>>(1), Some("foobar"));
+    assert_eq!(rows[1].get::<_, i32>(0), 2);
+    assert_eq!(rows[1].get::<_, Option<&str>>(1), None);
+}
+
+#[tokio::test]
+async fn write_many_rows() {
+    let client = connect().await;
+
+    client
+        .batch_execute("CREATE TEMPORARY TABLE foo (id INT, bar TEXT)")
+        .await
+        .unwrap();
+
+    let stream = BinaryCopyStream::new(&[Type::INT4, Type::TEXT], |mut w| async move {
+        for i in 0..10_000i32 {
+            w.write(&i).await?;
+            w.write(&format!("the value for {}", i)).await?;
+        }
+
+        Ok(())
+    });
+
+    client.copy_in("COPY foo (id, bar) FROM STDIN BINARY", &[], stream).await.unwrap();
+
+    let rows = client.query("SELECT id, bar FROM foo ORDER BY id", &[]).await.unwrap();
+    for (i, row) in rows.iter().enumerate() {
+        assert_eq!(row.get::<_, i32>(0), i as i32);
+        assert_eq!(row.get::<_, &str>(1), format!("the value for {}", i));
+    }
+}
+
+#[tokio::test]
+async fn write_big_rows() {
+    let client = connect().await;
+
+    client.batch_execute("CREATE TEMPORARY TABLE foo (id INT, bar BYTEA)").await.unwrap();
+
+    let stream = BinaryCopyStream::new(&[Type::INT4, Type::BYTEA], |mut w| {
+        async move {
+            for i in 0..2i32 {
+                w.write(&i).await.unwrap();
+                w.write(&vec![i as u8; 128 * 1024]).await.unwrap();
+            }
+
+            Ok(())
+        }
+    });
+
+    client.copy_in("COPY foo (id, bar) FROM STDIN BINARY", &[], stream).await.unwrap();
+
+    let rows = client.query("SELECT id, bar FROM foo ORDER BY id", &[]).await.unwrap();
+    for (i, row) in rows.iter().enumerate() {
+        assert_eq!(row.get::<_, i32>(0), i as i32);
+        assert_eq!(row.get::<_, &[u8]>(1), &*vec![i as u8; 128 * 1024]);
+    }
+}