From 0e487b34993e8bc8a5358468ef15b01f7cc30cbb Mon Sep 17 00:00:00 2001
From: Tomasz Grabiec <tgrabiec@scylladb.com>
Date: Mon, 19 Dec 2016 13:39:24 +0100
Subject: [PATCH] db: Compute key hash once in partition_presence_checker

I measured reduction of cache update time by 20% for 6 sstables and by
40% for 16.

Refs #1943.
---
 database.cc          | 3 ++-
 sstables/sstables.cc | 4 ++++
 sstables/sstables.hh | 6 ++++++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/database.cc b/database.cc
index 1c2e488d00..a84b4d85c3 100644
--- a/database.cc
+++ b/database.cc
@@ -146,8 +146,9 @@ column_family::make_partition_presence_checker(lw_shared_ptr<sstables::sstable_s
         if (sst.empty()) {
             return partition_presence_checker_result::definitely_doesnt_exist;
         }
+        auto hk = sstables::sstable::make_hashed_key(*_schema, key.key());
         for (auto&& s : sst) {
-            if (s->filter_has_key(*_schema, key.key())) {
+            if (s->filter_has_key(hk)) {
                 return partition_presence_checker_result::maybe_exists;
             }
         }
diff --git a/sstables/sstables.cc b/sstables/sstables.cc
index b46c9ccb48..0760df9df4 100644
--- a/sstables/sstables.cc
+++ b/sstables/sstables.cc
@@ -2627,6 +2627,10 @@ sstable::get_shards_for_this_sstable() const {
     return boost::copy_range<std::vector<unsigned>>(shards);
 }
 
+utils::hashed_key sstable::make_hashed_key(const schema& s, const partition_key& key) {
+    return utils::make_hashed_key(static_cast<bytes_view>(key::from_partition_key(s, key)));
+}
+
 std::ostream&
 operator<<(std::ostream& os, const sstable_to_delete& std) {
     return os << std.name << "(" << (std.shared ? "shared" : "unshared") << ")";
diff --git a/sstables/sstables.hh b/sstables/sstables.hh
index 8fdcd3c9e0..749476280d 100644
--- a/sstables/sstables.hh
+++ b/sstables/sstables.hh
@@ -607,10 +607,16 @@ public:
         return _filter->is_present(bytes_view(key));
     }
 
+    bool filter_has_key(utils::hashed_key key) {
+        return _filter->is_present(key);
+    }
+
     bool filter_has_key(const schema& s, partition_key_view key) {
         return filter_has_key(key::from_partition_key(s, key));
     }
 
+    static utils::hashed_key make_hashed_key(const schema& s, const partition_key& key);
+
     uint64_t filter_get_false_positive() {
         return _filter_tracker.false_positive;
     }