From 183554cbc4f57fa095726ce81ce50edb8db8085d Mon Sep 17 00:00:00 2001
From: Tomasz Grabiec <tgrabiec@scylladb.com>
Date: Fri, 8 Dec 2017 10:04:11 +0100
Subject: [PATCH] mvcc: Optimize partition_snapshot::range_tombstones() for
 single version case

---
 partition_version.cc | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/partition_version.cc b/partition_version.cc
index 3141cf742c..b72052cd59 100644
--- a/partition_version.cc
+++ b/partition_version.cc
@@ -566,11 +566,17 @@ lw_shared_ptr<partition_snapshot> partition_entry::read(logalloc::region& r,
 std::vector<range_tombstone>
 partition_snapshot::range_tombstones(const ::schema& s, position_in_partition_view start, position_in_partition_view end)
 {
+    partition_version* v = &*version();
+    if (!v->next()) {
+        return boost::copy_range<std::vector<range_tombstone>>(
+            v->partition().row_tombstones().slice(s, start, end));
+    }
     range_tombstone_list list(s);
-    for (auto&& v : versions()) {
-        for (auto&& rt : v.partition().row_tombstones().slice(s, start, end)) {
+    while (v) {
+        for (auto&& rt : v->partition().row_tombstones().slice(s, start, end)) {
             list.apply(s, rt);
         }
+        v = v->next();
     }
     return boost::copy_range<std::vector<range_tombstone>>(list.slice(s, start, end));
 }