diff --git a/backend/windmill-object-store/src/lib.rs b/backend/windmill-object-store/src/lib.rs
index 11235a8533..78a0e22c92 100644
--- a/backend/windmill-object-store/src/lib.rs
+++ b/backend/windmill-object-store/src/lib.rs
@@ -979,25 +979,67 @@ impl Write for ChannelWriter {
 }
 
 #[cfg(not(feature = "parquet"))]
-pub async fn convert_json_line_stream<E: Into<anyhow::Error>>(
-    mut _stream: impl futures::TryStreamExt<Item = Result<serde_json::Value, E>> + Unpin,
+#[derive(Debug, Clone, Copy, Default)]
+pub struct IngestStats {
+    pub rows: u64,
+    pub bytes: u64,
+    pub elapsed: std::time::Duration,
+    pub fetch_wait: std::time::Duration,
+    pub write_time: std::time::Duration,
+    pub first_row_latency: Option<std::time::Duration>,
+}
+
+#[cfg(not(feature = "parquet"))]
+pub async fn convert_json_line_stream<V, E>(
+    mut _stream: impl futures::TryStreamExt<Item = Result<V, E>> + Unpin,
     _output_format: S3ModeFormat,
-) -> anyhow::Result<impl futures::TryStreamExt<Item = anyhow::Result<bytes::Bytes>>> {
-    Ok(async_stream::stream! {
+    _progress: Option<tokio::sync::mpsc::Sender<IngestStats>>,
+) -> anyhow::Result<(
+    impl futures::TryStreamExt<Item = anyhow::Result<bytes::Bytes>>,
+    IngestStats,
+)>
+where
+    V: serde::Serialize,
+    E: Into<anyhow::Error>,
+{
+    let stream = async_stream::stream! {
         yield Err(anyhow::anyhow!("Parquet feature is not enabled. Cannot convert JSON line stream."));
-    })
+    };
+    Ok((stream, IngestStats::default()))
 }
 
 #[cfg(feature = "parquet")]
-pub async fn convert_json_line_stream<E: Into<anyhow::Error>>(
-    mut stream: impl TryStreamExt<Item = Result<serde_json::Value, E>> + Unpin,
+#[derive(Debug, Clone, Copy)]
+pub struct IngestStats {
+    pub rows: u64,
+    pub bytes: u64,
+    pub elapsed: std::time::Duration,
+    pub fetch_wait: std::time::Duration,
+    pub write_time: std::time::Duration,
+    pub first_row_latency: Option<std::time::Duration>,
+}
+
+#[cfg(feature = "parquet")]
+pub async fn convert_json_line_stream<V, E>(
+    mut stream: impl TryStreamExt<Item = Result<V, E>> + Unpin,
     output_format: S3ModeFormat,
-) -> anyhow::Result<impl TryStreamExt<Item = anyhow::Result<bytes::Bytes>>> {
+    progress: Option<tokio::sync::mpsc::Sender<IngestStats>>,
+) -> anyhow::Result<(
+    impl TryStreamExt<Item = anyhow::Result<bytes::Bytes>>,
+    IngestStats,
+)>
+where
+    V: serde::Serialize,
+    E: Into<anyhow::Error>,
+{
     const MAX_MPSC_SIZE: usize = 1000;
+    const WRITE_BUF_CAPACITY: usize = 256 * 1024;
+    const PROGRESS_INTERVAL_SECS: u64 = 10;
 
     use datafusion::{execution::context::SessionContext, prelude::NdJsonReadOptions};
     use futures::StreamExt;
     use std::path::PathBuf;
+    use std::time::{Duration, Instant};
     use tokio::io::AsyncWriteExt;
 
     let mut path = PathBuf::from(std::env::temp_dir());
@@ -1006,26 +1048,78 @@ pub async fn convert_json_line_stream<E: Into<anyhow::Error>>(
         .to_str()
         .ok_or_else(|| anyhow::anyhow!("Invalid path"))?;
 
-    let mut file: tokio::fs::File = tokio::fs::File::create(&path).await.map_err(to_anyhow)?;
+    let file: tokio::fs::File = tokio::fs::File::create(&path).await.map_err(to_anyhow)?;
+    let mut file = tokio::io::BufWriter::with_capacity(WRITE_BUF_CAPACITY, file);
 
-    while let Some(chunk) = stream.next().await {
-        match chunk {
-            Ok(chunk) => {
-                let b: bytes::Bytes = serde_json::to_string(&chunk)?.into();
-                file.write_all(&b).await?;
-                file.write_all(b"\n").await?;
+    let ingest_start = Instant::now();
+    let mut first_row_latency: Option<Duration> = None;
+    let mut row_count: u64 = 0;
+    let mut bytes_written: u64 = 0;
+    let mut write_time = Duration::ZERO;
+    let mut progress_timer = tokio::time::interval(Duration::from_secs(PROGRESS_INTERVAL_SECS));
+    progress_timer.tick().await; // drop the immediate tick
+    let build_stats = |row_count: u64,
+                       bytes_written: u64,
+                       write_time: Duration,
+                       first_row_latency: Option<Duration>,
+                       elapsed: Duration|
+     -> IngestStats {
+        IngestStats {
+            rows: row_count,
+            bytes: bytes_written,
+            elapsed,
+            fetch_wait: elapsed.saturating_sub(write_time),
+            write_time,
+            first_row_latency,
+        }
+    };
+
+    let mut done = false;
+    while !done {
+        tokio::select! {
+            chunk = stream.next() => {
+                match chunk {
+                    Some(Ok(chunk)) => {
+                        if first_row_latency.is_none() {
+                            first_row_latency = Some(ingest_start.elapsed());
+                        }
+                        let t_write = Instant::now();
+                        let mut s = serde_json::to_string(&chunk)?;
+                        s.push('\n');
+                        bytes_written += s.len() as u64;
+                        file.write_all(s.as_bytes()).await?;
+                        write_time += t_write.elapsed();
+                        row_count += 1;
+                    }
+                    Some(Err(e)) => {
+                        tokio::fs::remove_file(&path).await?;
+                        return Err(e.into());
+                    }
+                    None => done = true,
+                }
             }
-            Err(e) => {
-                tokio::fs::remove_file(&path).await?;
-                return Err(e.into());
+            _ = progress_timer.tick(), if progress.is_some() => {
+                let stats = build_stats(row_count, bytes_written, write_time, first_row_latency, ingest_start.elapsed());
+                if let Some(tx) = &progress {
+                    let _ = tx.try_send(stats);
+                }
             }
         }
     }
 
     file.flush().await?;
+    let file = file.into_inner();
     file.sync_all().await?;
     drop(file);
 
+    let ingest_stats = build_stats(
+        row_count,
+        bytes_written,
+        write_time,
+        first_row_latency,
+        ingest_start.elapsed(),
+    );
+
     let ctx = SessionContext::new();
     ctx.register_json("my_table", path_str, NdJsonReadOptions::default())
         .await
@@ -1109,7 +1203,10 @@ pub async fn convert_json_line_stream<E: Into<anyhow::Error>>(
         Ok::<_, anyhow::Error>(())
     });
 
-    Ok(tokio_stream::wrappers::ReceiverStream::new(rx))
+    Ok((
+        tokio_stream::wrappers::ReceiverStream::new(rx),
+        ingest_stats,
+    ))
 }
 
 lazy_static::lazy_static! {
diff --git a/backend/windmill-worker/src/bigquery_executor.rs b/backend/windmill-worker/src/bigquery_executor.rs
index b092e135b6..c9e803deaf 100644
--- a/backend/windmill-worker/src/bigquery_executor.rs
+++ b/backend/windmill-worker/src/bigquery_executor.rs
@@ -203,8 +203,8 @@ fn do_bigquery_inner<'a>(
                             }
                         };
 
-                        let stream =
-                            convert_json_line_stream(rows_stream.boxed(), s3.format).await?;
+                        let (stream, _) =
+                            convert_json_line_stream(rows_stream.boxed(), s3.format, None).await?;
                         s3.upload(stream.boxed()).await?;
 
                         return Ok(vec![to_raw_value(&s3.to_return_s3_obj())]);
diff --git a/backend/windmill-worker/src/mssql_executor.rs b/backend/windmill-worker/src/mssql_executor.rs
index c1f8ae2fe7..d7be6b0d1c 100644
--- a/backend/windmill-worker/src/mssql_executor.rs
+++ b/backend/windmill-worker/src/mssql_executor.rs
@@ -244,19 +244,61 @@ pub async fn do_mssql(
         // fetching data in an asynchronous manner, if needed.
 
         if let Some(s3) = s3 {
+            let s3_format = s3.format;
             let rows_stream = async_stream::stream! {
                 let mut stream = prepared_query.query(&mut client).await.map_err(to_anyhow)?.into_row_stream().map(|row| {
-                    let raw_value = row_to_json(row.map_err(to_anyhow)?).map_err(to_anyhow);
-                    let json = raw_value.and_then(|raw_value| serde_json::from_str(raw_value.get()).map_err(to_anyhow));
-                    json
+                    row_to_json(row.map_err(to_anyhow)?).map_err(to_anyhow)
                 });
                 while let Some(row) = stream.next().await {
                     yield row;
                 }
             };
 
-            let stream = convert_json_line_stream(rows_stream.boxed(), s3.format).await?;
+            let (progress_tx, mut progress_rx) =
+                tokio::sync::mpsc::channel::<windmill_object_store::IngestStats>(8);
+            let progress_conn = conn.clone();
+            let progress_job_id = job.id;
+            let progress_workspace = job.workspace_id.clone();
+            let progress_task = tokio::spawn(async move {
+                while let Some(stats) = progress_rx.recv().await {
+                    let logs = format!(
+                        "\nMSSQL s3 stream progress: {} rows, {:.1} MB | elapsed {:.1}s (db-fetch {:.1}s, write {:.1}s)",
+                        stats.rows,
+                        stats.bytes as f64 / 1_048_576.0,
+                        stats.elapsed.as_secs_f64(),
+                        stats.fetch_wait.as_secs_f64(),
+                        stats.write_time.as_secs_f64(),
+                    );
+                    append_logs(&progress_job_id, &progress_workspace, logs, &progress_conn).await;
+                }
+            });
+
+            let (stream, ingest_stats) =
+                convert_json_line_stream(rows_stream.boxed(), s3_format, Some(progress_tx)).await?;
+            let _ = progress_task.await;
+
+            let ingest_log = format!(
+                "\nMSSQL s3 stream ingest done ({:?}): {} rows, {:.1} MB in {:.2}s (db-fetch {:.2}s, write {:.2}s, first row after {:.2}s)",
+                s3_format,
+                ingest_stats.rows,
+                ingest_stats.bytes as f64 / 1_048_576.0,
+                ingest_stats.elapsed.as_secs_f64(),
+                ingest_stats.fetch_wait.as_secs_f64(),
+                ingest_stats.write_time.as_secs_f64(),
+                ingest_stats.first_row_latency.unwrap_or_default().as_secs_f64(),
+            );
+            append_logs(&job.id, &job.workspace_id, ingest_log, conn).await;
+
+            let upload_start = std::time::Instant::now();
             s3.upload(stream.boxed()).await?;
+            let upload_elapsed = upload_start.elapsed();
+
+            let final_log = format!(
+                "\nMSSQL s3 stream upload+transcode done: {:.2}s | total {:.2}s",
+                upload_elapsed.as_secs_f64(),
+                (ingest_stats.elapsed + upload_elapsed).as_secs_f64(),
+            );
+            append_logs(&job.id, &job.workspace_id, final_log, conn).await;
 
             Ok(to_raw_value(&s3.to_return_s3_obj()))
         } else {
diff --git a/backend/windmill-worker/src/mysql_executor.rs b/backend/windmill-worker/src/mysql_executor.rs
index a3a9468459..aee7de16f8 100644
--- a/backend/windmill-worker/src/mysql_executor.rs
+++ b/backend/windmill-worker/src/mysql_executor.rs
@@ -107,7 +107,8 @@ fn do_mysql_inner<'a>(
                 }
             };
 
-            let stream = convert_json_line_stream(rows_stream.boxed(), s3.format).await?;
+            let (stream, _) =
+                convert_json_line_stream(rows_stream.boxed(), s3.format, None).await?;
             s3.upload(stream.boxed()).await?;
 
             Ok(vec![to_raw_value(&s3.to_return_s3_obj())])
diff --git a/backend/windmill-worker/src/oracledb_executor.rs b/backend/windmill-worker/src/oracledb_executor.rs
index bc90ba7811..55ffac467b 100644
--- a/backend/windmill-worker/src/oracledb_executor.rs
+++ b/backend/windmill-worker/src/oracledb_executor.rs
@@ -162,7 +162,8 @@ pub fn do_oracledb_inner<'a>(
             }
 
             if let Some(s3) = s3 {
-                let stream = convert_json_line_stream(rows_stream.boxed(), s3.format).await?;
+                let (stream, _) =
+                    convert_json_line_stream(rows_stream.boxed(), s3.format, None).await?;
                 s3.upload(stream.boxed()).await?;
                 return Ok(vec![to_raw_value(&s3.to_return_s3_obj())]);
             } else {
diff --git a/backend/windmill-worker/src/pg_executor.rs b/backend/windmill-worker/src/pg_executor.rs
index fbe0cfbcb7..2e577da6a8 100644
--- a/backend/windmill-worker/src/pg_executor.rs
+++ b/backend/windmill-worker/src/pg_executor.rs
@@ -203,7 +203,8 @@ fn do_postgresql_inner<'a>(
                 row_result.and_then(|row| postgres_row_to_json_value(row).map_err(to_anyhow))
             });
 
-            let stream = convert_json_line_stream(rows_stream.boxed(), s3.format).await?;
+            let (stream, _) =
+                convert_json_line_stream(rows_stream.boxed(), s3.format, None).await?;
             s3.upload(stream.boxed()).await?;
 
             return Ok(vec![to_raw_value(&s3.to_return_s3_obj())]);
diff --git a/backend/windmill-worker/src/snowflake_executor.rs b/backend/windmill-worker/src/snowflake_executor.rs
index 90d06287bc..0873624f54 100644
--- a/backend/windmill-worker/src/snowflake_executor.rs
+++ b/backend/windmill-worker/src/snowflake_executor.rs
@@ -501,7 +501,8 @@ fn do_snowflake_inner<'a>(
             if let Some(s3) = s3 {
                 let rows_stream =
                     rows_stream.map(|r| serde_json::value::to_value(&r?).map_err(to_anyhow));
-                let stream = convert_json_line_stream(rows_stream.boxed(), s3.format).await?;
+                let (stream, _) =
+                    convert_json_line_stream(rows_stream.boxed(), s3.format, None).await?;
                 s3.upload(stream.boxed()).await?;
                 Ok(vec![to_raw_value(&s3.to_return_s3_obj())])
             } else {