From d0a00f348980ce75ecc0b1afb4151b2c8b9923bc Mon Sep 17 00:00:00 2001
From: Gleb Natapov <gleb@scylladb.com>
Date: Tue, 2 Apr 2024 16:33:16 +0300
Subject: [PATCH] storage_service: yield in get_system_mutations

Yield in a loop that converts a result to canonical_mutation. We
observed stalls for very large tables.
---
 service/storage_service.cc | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/service/storage_service.cc b/service/storage_service.cc
index 1966ef4985..08e40bbbd6 100644
--- a/service/storage_service.cc
+++ b/service/storage_service.cc
@@ -6390,10 +6390,10 @@ future<std::vector<canonical_mutation>> storage_service::get_system_mutations(sc
     std::vector<canonical_mutation> result;
     auto rs = co_await db::system_keyspace::query_mutations(_db, schema);
     result.reserve(rs->partitions().size());
-    boost::range::transform(
-            rs->partitions(), std::back_inserter(result), [schema] (const partition& p) {
-        return canonical_mutation{p.mut().unfreeze(schema)};
-    });
+    for (const auto& p : rs->partitions()) {
+        result.emplace_back(canonical_mutation{p.mut().unfreeze(schema)});
+        co_await coroutine::maybe_yield();
+    }
     co_return result;
 }