From 68cb2e66fc2db4f58a82a1b1a0c69fda6cddcde7 Mon Sep 17 00:00:00 2001
From: Pavel Emelyanov <xemul@scylladb.com>
Date: Tue, 28 Nov 2023 14:07:04 +0300
Subject: [PATCH] discard_sstables: Do not allocate pruner

This allocation remained from the pre-coroutine times of the method. Now
the contents of prumer -- refernce on table, vector and replay_position
can reside on coroutine frame

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
---
 replica/table.cc | 23 +++++++++--------------
 1 file changed, 9 insertions(+), 14 deletions(-)

diff --git a/replica/table.cc b/replica/table.cc
index d4042c5de8..f5054fc3d5 100644
--- a/replica/table.cc
+++ b/replica/table.cc
@@ -2011,8 +2011,7 @@ future<db::replay_position> table::discard_sstables(db_clock::time_point truncat
         return _compaction_manager.compaction_disabled(cg->as_table_state());
     }));
 
-    struct pruner {
-        column_family& cf;
+        column_family& cf = *this;
         db::replay_position rp;
         struct removed_sstable {
             compaction_group& cg;
@@ -2021,16 +2020,13 @@ future<db::replay_position> table::discard_sstables(db_clock::time_point truncat
         };
         std::vector<removed_sstable> remove;
 
-        pruner(column_family& cf)
-            : cf(cf) {}
-
-        void prune(compaction_group& cg, db_clock::time_point truncated_at) {
+        auto prune = [&] (compaction_group& cg, db_clock::time_point truncated_at) {
             auto gc_trunc = to_gc_clock(truncated_at);
 
             auto pruned = make_lw_shared<sstables::sstable_set>(cf._compaction_strategy.make_sstable_set(cf._schema));
             auto maintenance_pruned = cf.make_maintenance_sstable_set();
 
-            auto prune = [this, &cg, &gc_trunc] (lw_shared_ptr<sstables::sstable_set>& pruned,
+            auto prune = [&] (lw_shared_ptr<sstables::sstable_set>& pruned,
                                             const lw_shared_ptr<sstables::sstable_set>& pruning,
                                             replica::enable_backlog_tracker enable_backlog_tracker) mutable {
                 pruning->for_each_sstable([&] (const sstables::shared_sstable& p) mutable {
@@ -2047,26 +2043,25 @@ future<db::replay_position> table::discard_sstables(db_clock::time_point truncat
 
             cg.set_main_sstables(std::move(pruned));
             cg.set_maintenance_sstables(std::move(maintenance_pruned));
-        }
-    };
-    auto p = make_lw_shared<pruner>(*this);
-    co_await _cache.invalidate(row_cache::external_updater([this, p, truncated_at] {
+        };
+
+    co_await _cache.invalidate(row_cache::external_updater([this, &prune, truncated_at] {
         // FIXME: the following isn't exception safe.
         for (const compaction_group_ptr& cg : compaction_groups()) {
-            p->prune(*cg, truncated_at);
+            prune(*cg, truncated_at);
         }
         refresh_compound_sstable_set();
         tlogger.debug("cleaning out row cache");
     }));
     rebuild_statistics();
-    co_await coroutine::parallel_for_each(p->remove, [this, p] (pruner::removed_sstable& r) -> future<> {
+    co_await coroutine::parallel_for_each(remove, [this] (removed_sstable& r) -> future<> {
         if (r.enable_backlog_tracker) {
             remove_sstable_from_backlog_tracker(r.cg.get_backlog_tracker(), r.sst);
         }
         co_await get_sstables_manager().delete_atomically({r.sst});
         erase_sstable_cleanup_state(r.sst);
     });
-    co_return p->rp;
+    co_return rp;
 }
 
 void table::mark_ready_for_writes(db::commitlog* cl) {