Default image compression to zstd at level 1 (#8677)

After the rollout has succeeded, we now set the default image
compression to be enabled.

We also remove its explicit mention from `neon_fixtures.py` added in
#8368 as it is now the default (and we switch to `zstd(1)` which is a
bit nicer on CPU time).

Part of https://github.com/neondatabase/neon/issues/5431

pageserver/src/config.rs

@@ -50,7 +50,6 @@ pub mod defaults {
         DEFAULT_HTTP_LISTEN_ADDR, DEFAULT_HTTP_LISTEN_PORT, DEFAULT_PG_LISTEN_ADDR,
         DEFAULT_PG_LISTEN_PORT,
     };
-    use pageserver_api::models::ImageCompressionAlgorithm;
     pub use storage_broker::DEFAULT_ENDPOINT as BROKER_DEFAULT_ENDPOINT;
 
     pub const DEFAULT_WAIT_LSN_TIMEOUT: &str = "300 s";
@@ -90,8 +89,7 @@ pub mod defaults {
 
     pub const DEFAULT_MAX_VECTORED_READ_BYTES: usize = 128 * 1024; // 128 KiB
 
-    pub const DEFAULT_IMAGE_COMPRESSION: ImageCompressionAlgorithm =
-        ImageCompressionAlgorithm::Disabled;
+    pub const DEFAULT_IMAGE_COMPRESSION: &str = "zstd(1)";
 
     pub const DEFAULT_VALIDATE_VECTORED_GET: bool = false;
 
@@ -478,7 +476,7 @@ impl PageServerConfigBuilder {
             max_vectored_read_bytes: Set(MaxVectoredReadBytes(
                 NonZeroUsize::new(DEFAULT_MAX_VECTORED_READ_BYTES).unwrap(),
             )),
-            image_compression: Set(DEFAULT_IMAGE_COMPRESSION),
+            image_compression: Set(DEFAULT_IMAGE_COMPRESSION.parse().unwrap()),
             ephemeral_bytes_per_memory_kb: Set(DEFAULT_EPHEMERAL_BYTES_PER_MEMORY_KB),
             l0_flush: Set(L0FlushConfig::default()),
             compact_level0_phase1_value_access: Set(CompactL0Phase1ValueAccess::default()),
@@ -1065,7 +1063,7 @@ impl PageServerConf {
                 NonZeroUsize::new(defaults::DEFAULT_MAX_VECTORED_READ_BYTES)
                     .expect("Invalid default constant"),
             ),
-            image_compression: defaults::DEFAULT_IMAGE_COMPRESSION,
+            image_compression: defaults::DEFAULT_IMAGE_COMPRESSION.parse().unwrap(),
             ephemeral_bytes_per_memory_kb: defaults::DEFAULT_EPHEMERAL_BYTES_PER_MEMORY_KB,
             l0_flush: L0FlushConfig::default(),
             compact_level0_phase1_value_access: CompactL0Phase1ValueAccess::default(),
@@ -1305,7 +1303,7 @@ background_task_maximum_delay = '334 s'
                     NonZeroUsize::new(defaults::DEFAULT_MAX_VECTORED_READ_BYTES)
                         .expect("Invalid default constant")
                 ),
-                image_compression: defaults::DEFAULT_IMAGE_COMPRESSION,
+                image_compression: defaults::DEFAULT_IMAGE_COMPRESSION.parse().unwrap(),
                 ephemeral_bytes_per_memory_kb: defaults::DEFAULT_EPHEMERAL_BYTES_PER_MEMORY_KB,
                 l0_flush: L0FlushConfig::default(),
                 compact_level0_phase1_value_access: CompactL0Phase1ValueAccess::default(),
@@ -1378,7 +1376,7 @@ background_task_maximum_delay = '334 s'
                     NonZeroUsize::new(defaults::DEFAULT_MAX_VECTORED_READ_BYTES)
                         .expect("Invalid default constant")
                 ),
-                image_compression: defaults::DEFAULT_IMAGE_COMPRESSION,
+                image_compression: defaults::DEFAULT_IMAGE_COMPRESSION.parse().unwrap(),
                 ephemeral_bytes_per_memory_kb: defaults::DEFAULT_EPHEMERAL_BYTES_PER_MEMORY_KB,
                 l0_flush: L0FlushConfig::default(),
                 compact_level0_phase1_value_access: CompactL0Phase1ValueAccess::default(),

pageserver/src/tenant/storage_layer/split_writer.rs

@@ -208,6 +208,8 @@ impl SplitDeltaLayerWriter {
 
 #[cfg(test)]
 mod tests {
+    use rand::{RngCore, SeedableRng};
+
     use crate::{
         tenant::{
             harness::{TenantHarness, TIMELINE_ID},
@@ -229,7 +231,10 @@ mod tests {
     }
 
     fn get_large_img() -> Bytes {
-        vec![0; 8192].into()
+        let mut rng = rand::rngs::SmallRng::seed_from_u64(42);
+        let mut data = vec![0; 8192];
+        rng.fill_bytes(&mut data);
+        data.into()
     }
 
     #[tokio::test]

test_runner/fixtures/neon_fixtures.py

@@ -1162,7 +1162,6 @@ class NeonEnv:
                 "listen_http_addr": f"localhost:{pageserver_port.http}",
                 "pg_auth_type": pg_auth_type,
                 "http_auth_type": http_auth_type,
-                "image_compression": "zstd",
             }
             if self.pageserver_virtual_file_io_engine is not None:
                 ps_cfg["virtual_file_io_engine"] = self.pageserver_virtual_file_io_engine