Enable consensus compaction by default (#5903)

* Enable consensus compaction by default

* Also set new compaction default in code

config/config.yaml

@@ -324,6 +324,12 @@ cluster:
     # We encourage you NOT to change this parameter unless you know what you are doing.
     tick_period_ms: 100
 
+    # Compact consensus operations once we have this amount of applied
+    # operations. Allows peers to join quickly with a consensus snapshot without
+    # replaying a huge amount of operations.
+    # If 0 - disable compaction
+    compact_wal_entries: 128
+
 # Set to true to prevent service from sending usage statistics to the developers.
 # Read more: https://qdrant.tech/documentation/guides/telemetry
 telemetry_disabled: false

src/settings.rs

@@ -114,8 +114,9 @@ pub struct ConsensusConfig {
     #[validate(range(min = 1))]
     #[serde(default = "default_message_timeout_tics")]
     pub message_timeout_ticks: u64,
-    #[serde(default)]
-    pub compact_wal_entries: u64, // compact WAL when it grows to enough applied entries
+    /// Compact WAL when it grows to enough applied entries
+    #[serde(default = "default_compact_wal_entries")]
+    pub compact_wal_entries: u64,
 }
 
 impl Default for ConsensusConfig {
@@ -125,7 +126,7 @@ impl Default for ConsensusConfig {
             tick_period_ms: default_tick_period_ms(),
             bootstrap_timeout_sec: default_bootstrap_timeout_sec(),
             message_timeout_ticks: default_message_timeout_tics(),
-            compact_wal_entries: 0,
+            compact_wal_entries: default_compact_wal_entries(),
         }
     }
 }
@@ -383,6 +384,10 @@ const fn default_message_timeout_tics() -> u64 {
     10
 }
 
+const fn default_compact_wal_entries() -> u64 {
+    128
+}
+
 #[allow(clippy::unnecessary_wraps)] // Used as serde default
 const fn default_tls_cert_ttl() -> Option<u64> {
     // Default one hour