Add autovector::reserve()

topling · Sep 27, 2021 · c0aad3c · c0aad3c
1 parent e4e84e1
commit c0aad3c
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diff --git a/db/db_impl/db_impl.cc b/db/db_impl/db_impl.cc
@@ -2297,6 +2297,7 @@ void DBImpl::MultiGet(const ReadOptions& read_options, const size_t num_keys,
 
   autovector<KeyContext, MultiGetContext::MAX_BATCH_SIZE> key_context;
   autovector<KeyContext*, MultiGetContext::MAX_BATCH_SIZE> sorted_keys;
+  key_context.reserve(num_keys);
   sorted_keys.resize(num_keys);
   for (size_t i = 0; i < num_keys; ++i) {
     key_context.emplace_back(column_families[i], keys[i], &values[i],
@@ -2451,6 +2452,7 @@ void DBImpl::MultiGet(const ReadOptions& read_options,
   }
   autovector<KeyContext, MultiGetContext::MAX_BATCH_SIZE> key_context;
   autovector<KeyContext*, MultiGetContext::MAX_BATCH_SIZE> sorted_keys;
+  key_context.reserve(num_keys);
   sorted_keys.resize(num_keys);
   for (size_t i = 0; i < num_keys; ++i) {
     key_context.emplace_back(column_family, keys[i], &values[i],

diff --git a/util/autovector.h b/util/autovector.h
@@ -220,6 +220,12 @@ class autovector {
     }
   }
 
+  void reserve(size_t cap) {
+    if (cap > kSize) {
+      vect_.reserve(cap - kSize);
+    }
+  }
+
   bool empty() const { return size() == 0; }
 
   const_reference operator[](size_type n) const {