From 92016ff9b1b4ccbb78d6ff3d202065443385794c Mon Sep 17 00:00:00 2001
From: Bojan Serafimov <bojan@pop-os.localdomain>
Date: Tue, 21 Nov 2023 12:45:21 -0500
Subject: [PATCH] wip

---
 pageserver/src/import_datadir.rs | 34 +++++++++++++++-----------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/pageserver/src/import_datadir.rs b/pageserver/src/import_datadir.rs
index bb21713fc0..91da9225d6 100644
--- a/pageserver/src/import_datadir.rs
+++ b/pageserver/src/import_datadir.rs
@@ -626,22 +626,21 @@ mod tests {
 
     #[tokio::test]
     async fn test_basic() -> anyhow::Result<()> {
+        // Bootstrap a real timeline. We can't use create_test_timeline because
+        // it doesn't create a real checkpoint, and Walingest::new tries to parse
+        // the garbage data.
         let pg_version = 15;
         let (tenant, ctx) = TenantHarness::create("test_basic")?.load().await;
-
-        // We can't use create_test_timeline because it doesn't create a real
-        // checkpoint, and Walingest::new tries to parse the garbage data.
         let tline = tenant
             .bootstrap_timeline(TIMELINE_ID, pg_version, &ctx)
             .await?;
 
-        // Steps to reconstruct this test data:
+        // Get test data. Steps to reconstruct it, if needed:
         // 1. Run the pgbench python test
         // 2. Take the first wal segment file from safekeeper
         // 3. Grep sk logs for "restart decoder" to get startpoint
         // 4. Run just the decoder from this test to get the endpoint.
         //    It's the last LSN the decoder will output.
-        let pg_version = 15;
         let path = "test_data/sk_wal_segment_from_pgbench";
         let startpoint = Lsn::from_hex("14AEC08").unwrap();
         let endpoint = Lsn::from_hex("1FFFF98").unwrap();
@@ -654,24 +653,23 @@ mod tests {
         let prof_guard = crate::profiling::profpoint_start();
         let started_at = std::time::Instant::now();
 
-        // Feed bytes to the decoder
-        // TODO try feeding in many small chunks
+        // Initialize walingest
         let xlogoff: usize = startpoint.segment_offset(WAL_SEGMENT_SIZE);
         let mut decoder = WalStreamDecoder::new(startpoint, pg_version);
-        // decoder.feed_bytes(&bytes[xlogoff..]);
-        for chunk in bytes[xlogoff..].chunks(50) {
-            decoder.feed_bytes(chunk);
-        }
-        println!("decoding {} bytes", bytes.len() - xlogoff);
-
-        // Decode and ingest wal
         let mut walingest = WalIngest::new(tline.as_ref(), startpoint, &ctx).await?;
         let mut modification = tline.begin_modification(endpoint);
         let mut decoded = DecodedWALRecord::default();
-        while let Some((lsn, recdata)) = decoder.poll_decode()? {
-            walingest
-                .ingest_record(recdata, lsn, &mut modification, &mut decoded, &ctx)
-                .await?;
+        println!("decoding {} bytes", bytes.len() - xlogoff);
+
+        // Decode and ingest wal. We process the wal in chunks because
+        // that's what happens when we get bytes from safekeepers.
+        for chunk in bytes[xlogoff..].chunks(50) {
+            decoder.feed_bytes(chunk);
+            while let Some((lsn, recdata)) = decoder.poll_decode()? {
+                walingest
+                    .ingest_record(recdata, lsn, &mut modification, &mut decoded, &ctx)
+                    .await?;
+            }
         }
 
         let duration = started_at.elapsed();