From 9c37bfc90abfb7aa653d8f3892d227ed16018492 Mon Sep 17 00:00:00 2001
From: John Spray <john@neon.tech>
Date: Thu, 10 Apr 2025 18:03:22 +0100
Subject: [PATCH] pageserver/tests: make image_layer_rewrite write less data
 (#11525)

## Problem

This test is slow to execute, particularly if you're on a slow
environment like vscode in a browser. Might have got much slower when we
switched to direct IO?

## Summary of changes

- Reduce the scale of the test by 10x, since there was nothing special
about the original size.
---
 .../src/tenant/storage_layer/image_layer.rs    | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/pageserver/src/tenant/storage_layer/image_layer.rs b/pageserver/src/tenant/storage_layer/image_layer.rs
index 3243b73942..72992e5031 100644
--- a/pageserver/src/tenant/storage_layer/image_layer.rs
+++ b/pageserver/src/tenant/storage_layer/image_layer.rs
@@ -1192,7 +1192,7 @@ mod test {
 
         // This key range contains several 0x8000 page stripes, only one of which belongs to shard zero
         let input_start = Key::from_hex("000000067f00000001000000ae0000000000").unwrap();
-        let input_end = Key::from_hex("000000067f00000001000000ae0000020000").unwrap();
+        let input_end = Key::from_hex("000000067f00000001000000ae0000002000").unwrap();
         let range = input_start..input_end;
 
         // Build an image layer to filter
@@ -1235,7 +1235,7 @@ mod test {
             let shard_identity = ShardIdentity::new(
                 ShardNumber(shard_number),
                 shard_count,
-                ShardStripeSize(0x8000),
+                ShardStripeSize(0x800),
             )
             .unwrap();
             let harness = TenantHarness::create_custom(
@@ -1287,12 +1287,12 @@ mod test {
 
             // This exact size and those below will need updating as/when the layer encoding changes, but
             // should be deterministic for a given version of the format, as we used no randomness generating the input.
-            assert_eq!(original_size, 1597440);
+            assert_eq!(original_size, 122880);
 
             match shard_number {
                 0 => {
                     // We should have written out just one stripe for our shard identity
-                    assert_eq!(wrote_keys, 0x8000);
+                    assert_eq!(wrote_keys, 0x800);
                     let replacement = replacement.unwrap();
 
                     // We should have dropped some of the data
@@ -1300,7 +1300,7 @@ mod test {
                     assert!(replacement.metadata().file_size > 0);
 
                     // Assert that we dropped ~3/4 of the data.
-                    assert_eq!(replacement.metadata().file_size, 417792);
+                    assert_eq!(replacement.metadata().file_size, 49152);
                 }
                 1 => {
                     // Shard 1 has no keys in our input range
@@ -1309,19 +1309,19 @@ mod test {
                 }
                 2 => {
                     // Shard 2 has one stripes in the input range
-                    assert_eq!(wrote_keys, 0x8000);
+                    assert_eq!(wrote_keys, 0x800);
                     let replacement = replacement.unwrap();
                     assert!(replacement.metadata().file_size < original_size);
                     assert!(replacement.metadata().file_size > 0);
-                    assert_eq!(replacement.metadata().file_size, 417792);
+                    assert_eq!(replacement.metadata().file_size, 49152);
                 }
                 3 => {
                     // Shard 3 has two stripes in the input range
-                    assert_eq!(wrote_keys, 0x10000);
+                    assert_eq!(wrote_keys, 0x1000);
                     let replacement = replacement.unwrap();
                     assert!(replacement.metadata().file_size < original_size);
                     assert!(replacement.metadata().file_size > 0);
-                    assert_eq!(replacement.metadata().file_size, 811008);
+                    assert_eq!(replacement.metadata().file_size, 73728);
                 }
                 _ => unreachable!(),
             }