From ec75eac37d75d59bb04ff1290c9facdb2ccdac4e Mon Sep 17 00:00:00 2001
From: Duarte Nunes <duarte@scylladb.com>
Date: Mon, 14 Aug 2017 11:33:10 +0200
Subject: [PATCH] ring_position_exponential_vector_sharder: Take ranges by
 rvalue

Avoids some copies.

Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <20170814093310.29200-1-duarte@scylladb.com>
---
 dht/i_partitioner.cc     | 4 ++--
 dht/i_partitioner.hh     | 2 +-
 service/storage_proxy.cc | 7 ++++---
 service/storage_proxy.hh | 2 +-
 4 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/dht/i_partitioner.cc b/dht/i_partitioner.cc
index 3ed1a83ac5..93d253bf06 100644
--- a/dht/i_partitioner.cc
+++ b/dht/i_partitioner.cc
@@ -363,8 +363,8 @@ ring_position_exponential_sharder::next(const schema& s) {
 }
 
 
-ring_position_exponential_vector_sharder::ring_position_exponential_vector_sharder(const std::vector<nonwrapping_range<ring_position>>& ranges)
-        : _ranges(std::begin(ranges), std::end(ranges)) {
+ring_position_exponential_vector_sharder::ring_position_exponential_vector_sharder(const std::vector<nonwrapping_range<ring_position>>&& ranges) {
+    std::move(ranges.begin(), ranges.end(), std::back_inserter(_ranges));
     if (!_ranges.empty()) {
         _current_sharder.emplace(_ranges.front());
         _ranges.pop_front();
diff --git a/dht/i_partitioner.hh b/dht/i_partitioner.hh
index 068314f018..34609305a5 100644
--- a/dht/i_partitioner.hh
+++ b/dht/i_partitioner.hh
@@ -641,7 +641,7 @@ class ring_position_exponential_vector_sharder {
     stdx::optional<ring_position_exponential_sharder> _current_sharder;
     unsigned _element = 0;
 public:
-    explicit ring_position_exponential_vector_sharder(const std::vector<nonwrapping_range<ring_position>>& ranges);
+    explicit ring_position_exponential_vector_sharder(const std::vector<nonwrapping_range<ring_position>>&& ranges);
     stdx::optional<ring_position_exponential_vector_sharder_result> next(const schema& s);
 };
 
diff --git a/service/storage_proxy.cc b/service/storage_proxy.cc
index fc7d026d7b..6ca0fcb192 100644
--- a/service/storage_proxy.cc
+++ b/service/storage_proxy.cc
@@ -4073,18 +4073,19 @@ struct partition_range_and_sort_key {
 };
 
 future<foreign_ptr<lw_shared_ptr<reconcilable_result>>, cache_temperature>
-storage_proxy::query_nonsingular_mutations_locally(schema_ptr s, lw_shared_ptr<query::read_command> cmd, const dht::partition_range_vector& prs,
+storage_proxy::query_nonsingular_mutations_locally(schema_ptr s, lw_shared_ptr<query::read_command> cmd, const dht::partition_range_vector&& prs,
                                                    tracing::trace_state_ptr trace_state, uint64_t max_size) {
     // no one permitted us to modify *cmd, so make a copy
     auto shard_cmd = make_lw_shared<query::read_command>(*cmd);
+    auto range_count = static_cast<unsigned>(prs.size());
     return do_with(cmd,
             shard_cmd,
             0u,
             false,
-            static_cast<unsigned>(prs.size()),
+            range_count,
             std::unordered_map<element_and_shard, partition_range_and_sort_key>{},
             mutation_result_merger{s, cmd},
-            dht::ring_position_exponential_vector_sharder{prs},
+            dht::ring_position_exponential_vector_sharder{std::move(prs)},
             global_schema_ptr(s),
             tracing::global_trace_state_ptr(std::move(trace_state)),
             cache_temperature(0.0f),
diff --git a/service/storage_proxy.hh b/service/storage_proxy.hh
index f0253e1420..0046cc3541 100644
--- a/service/storage_proxy.hh
+++ b/service/storage_proxy.hh
@@ -279,7 +279,7 @@ private:
     template<typename Range>
     future<> mutate_internal(Range mutations, db::consistency_level cl, bool counter_write, tracing::trace_state_ptr tr_state, stdx::optional<clock_type::time_point> timeout_opt = { });
     future<foreign_ptr<lw_shared_ptr<reconcilable_result>>, cache_temperature> query_nonsingular_mutations_locally(
-            schema_ptr s, lw_shared_ptr<query::read_command> cmd, const dht::partition_range_vector& pr, tracing::trace_state_ptr trace_state, uint64_t max_size);
+            schema_ptr s, lw_shared_ptr<query::read_command> cmd, const dht::partition_range_vector&& pr, tracing::trace_state_ptr trace_state, uint64_t max_size);
 
     struct frozen_mutation_and_schema {
         frozen_mutation fm;