fix(udb): update backoff algo

Author: MasterPtato

engine/packages/api-peer/src/actors/kv_get.rs

@@ -1,6 +1,6 @@
 use anyhow::*;
-use base64::prelude::BASE64_STANDARD;
 use base64::Engine;
+use base64::prelude::BASE64_STANDARD;
 use pegboard_actor_kv as actor_kv;
 use rivet_api_builder::ApiCtx;
 use rivet_util::Id;

engine/packages/api-public/src/actors/kv_get.rs

@@ -65,7 +65,11 @@ async fn kv_get_inner(ctx: ApiCtx, path: KvGetPath) -> Result<Response> {
 		request_remote_datacenter_raw(
 			&ctx,
 			path.actor_id.label(),
-			&format!("/actors/{}/kv/keys/{}", path.actor_id, urlencoding::encode(&path.key)),
+			&format!(
+				"/actors/{}/kv/keys/{}",
+				path.actor_id,
+				urlencoding::encode(&path.key)
+			),
 			axum::http::Method::GET,
 			Option::<&()>::None,
 			Option::<&()>::None,

engine/packages/universaldb/src/utils/mod.rs

@@ -24,13 +24,26 @@ pub enum IsolationLevel {
 #[derive(Debug, Clone, Copy)]
 pub struct MaybeCommitted(pub bool);
 
+/// Calculate exponential backoff based on attempt.
+///
+/// Ours:
+///   0 -> 10ms + 0-1ms jitter
+///   1 -> 20ms + 0-2ms jitter
+///   2 -> 40ms + 0-4ms jitter
+///   ...
+///   7 (max) -> 1280ms + 0-128ms jitter
+/// FDB (see https://github.com/apple/foundationdb/blob/b1fbbd87a794b7c6c2f456925c45d8af339a8ae0/fdbclient/NativeAPI.actor.cpp#L4333 and https://github.com/apple/foundationdb/blob/b1fbbd87a794b7c6c2f456925c45d8af339a8ae0/fdbclient/ClientKnobs.cpp#L74-L76):
+///   0 -> 10ms
+///   1 -> 20ms
+///   2 -> 40ms
+///   ...
+///   X -> max 1s
 pub fn calculate_tx_retry_backoff(attempt: usize) -> u64 {
-	// TODO: Update this to mirror fdb 1:1:
-	// https://github.com/apple/foundationdb/blob/21407341d9b49e1d343514a7a5f395bd5f232079/fdbclient/NativeAPI.actor.cpp#L3162
+	let base = 2_u64.pow((attempt as u32).min(7));
+	let base_backoff_ms = base * 10;
 
-	let base_backoff_ms = 2_u64.pow((attempt as u32).min(10)) * 10;
-
-	let jitter_ms = rand::random::<u64>() % 100;
+	// Jitter is 0-10% of backoff ms
+	let jitter_ms = rand::random::<u64>() % base;
 
 	base_backoff_ms + jitter_ms
 }

engine/packages/universaldb/tests/rocksdb.rs

@@ -4,7 +4,10 @@ use anyhow::Context;
 use futures_util::StreamExt;
 use rivet_test_deps_docker::TestDatabase;
 use rocksdb::{OptimisticTransactionDB, Options, WriteOptions};
-use universaldb::{Database, utils::IsolationLevel::*};
+use universaldb::{
+	Database,
+	utils::{IsolationLevel::*, calculate_tx_retry_backoff},
+};
 use uuid::Uuid;
 
 #[tokio::test]
@@ -136,11 +139,3 @@ async fn rocksdb_udb() {
 		})
 		.await;
 }
-
-pub fn calculate_tx_retry_backoff(attempt: usize) -> u64 {
-	let base_backoff_ms = 2_u64.pow((attempt as u32).min(10)) * 10;
-
-	let jitter_ms = rand::random::<u64>() % 100;
-
-	base_backoff_ms + jitter_ms
-}