From 2c727f37fbacbb024077760f3449685ccfb9ece6 Mon Sep 17 00:00:00 2001
From: Tomasz Grabiec <tgrabiec@scylladb.com>
Date: Fri, 2 Jul 2021 01:09:16 +0200
Subject: [PATCH] api: Drop sstable index caches on system/drop_sstable_caches

---
 database.cc          | 5 +++++
 sstables/sstables.cc | 6 ++++++
 sstables/sstables.hh | 3 +++
 3 files changed, 14 insertions(+)

diff --git a/database.cc b/database.cc
index 13a262827b..d03d1b1a0a 100644
--- a/database.cc
+++ b/database.cc
@@ -1334,6 +1334,11 @@ database::drop_caches() const {
     for (auto&& e : tables) {
         table& t = *e.second;
         co_await t.get_row_cache().invalidate(row_cache::external_updater([] {}));
+
+        auto sstables = t.get_sstables();
+        for (sstables::shared_sstable sst : *sstables) {
+            co_await sst->drop_caches();
+        }
     }
     co_return;
 }
diff --git a/sstables/sstables.cc b/sstables/sstables.cc
index 126a8983a9..9c0eb90d1b 100644
--- a/sstables/sstables.cc
+++ b/sstables/sstables.cc
@@ -1396,6 +1396,12 @@ future<> sstable::create_data() noexcept {
     });
 }
 
+future<> sstable::drop_caches() {
+    return _cached_index_file->evict_gently().then([this] {
+        return _index_cache->evict_gently();
+    });
+}
+
 future<> sstable::read_filter(const io_priority_class& pc) {
     if (!has_component(component_type::Filter)) {
         _components->filter = std::make_unique<utils::filter::always_present_filter>();
diff --git a/sstables/sstables.hh b/sstables/sstables.hh
index 7012b6fd02..d41800bef6 100644
--- a/sstables/sstables.hh
+++ b/sstables/sstables.hh
@@ -815,6 +815,9 @@ public:
         return _origin;
     }
 
+    // Drops all evictable in-memory caches of on-disk content.
+    future<> drop_caches();
+
     // Allow the test cases from sstable_test.cc to test private methods. We use
     // a placeholder to avoid cluttering this class too much. The sstable_test class
     // will then re-export as public every method it needs.