Pass OptionTypeInfo maps by const& (#5295)

Summary:
In options_helper.cc various functions take a const unordered_map of
string -> TypeInfo for options handling. These functions pass by-value
the (const) maps, resulting in unnecessary copies.

Change to pass by reference.

This results in a noticable reduction in the amount of time spent
parsing options - in my case a set of unit tests using RocksDB which
call SetOptions() to modify options see a ~25% runtime reduction.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5295

Differential Revision: D15296334

Pulled By: riversand963

fbshipit-source-id: 4d4be3db635264943607911b296dda27fd7ce1a7
main
Dave Rigby 6 years ago committed by Facebook Github Bot
parent 468ca61105
commit 8149bb9d6a
  1. 12
      options/options_helper.cc

@ -255,7 +255,7 @@ const std::string kNameMergeOperator = "merge_operator";
template <typename T> template <typename T>
Status GetStringFromStruct( Status GetStringFromStruct(
std::string* opt_string, const T& options, std::string* opt_string, const T& options,
const std::unordered_map<std::string, OptionTypeInfo> type_info, const std::unordered_map<std::string, OptionTypeInfo>& type_info,
const std::string& delimiter); const std::string& delimiter);
namespace { namespace {
@ -350,7 +350,7 @@ bool FIFOCompactionOptionsSpecialCase(const std::string& opt_str,
template <typename T> template <typename T>
bool SerializeStruct( bool SerializeStruct(
const T& options, std::string* value, const T& options, std::string* value,
std::unordered_map<std::string, OptionTypeInfo> type_info_map) { const std::unordered_map<std::string, OptionTypeInfo>& type_info_map) {
std::string opt_str; std::string opt_str;
Status s = GetStringFromStruct(&opt_str, options, type_info_map, ";"); Status s = GetStringFromStruct(&opt_str, options, type_info_map, ";");
if (!s.ok()) { if (!s.ok()) {
@ -363,7 +363,7 @@ bool SerializeStruct(
template <typename T> template <typename T>
bool ParseSingleStructOption( bool ParseSingleStructOption(
const std::string& opt_val_str, T* options, const std::string& opt_val_str, T* options,
std::unordered_map<std::string, OptionTypeInfo> type_info_map) { const std::unordered_map<std::string, OptionTypeInfo>& type_info_map) {
size_t end = opt_val_str.find('='); size_t end = opt_val_str.find('=');
std::string key = opt_val_str.substr(0, end); std::string key = opt_val_str.substr(0, end);
std::string value = opt_val_str.substr(end + 1); std::string value = opt_val_str.substr(end + 1);
@ -380,7 +380,7 @@ bool ParseSingleStructOption(
template <typename T> template <typename T>
bool ParseStructOptions( bool ParseStructOptions(
const std::string& opt_str, T* options, const std::string& opt_str, T* options,
std::unordered_map<std::string, OptionTypeInfo> type_info_map) { const std::unordered_map<std::string, OptionTypeInfo>& type_info_map) {
assert(!opt_str.empty()); assert(!opt_str.empty());
size_t start = 0; size_t start = 0;
@ -1092,7 +1092,7 @@ Status ParseColumnFamilyOption(const std::string& name,
template <typename T> template <typename T>
bool SerializeSingleStructOption( bool SerializeSingleStructOption(
std::string* opt_string, const T& options, std::string* opt_string, const T& options,
const std::unordered_map<std::string, OptionTypeInfo> type_info, const std::unordered_map<std::string, OptionTypeInfo>& type_info,
const std::string& name, const std::string& delimiter) { const std::string& name, const std::string& delimiter) {
auto iter = type_info.find(name); auto iter = type_info.find(name);
if (iter == type_info.end()) { if (iter == type_info.end()) {
@ -1112,7 +1112,7 @@ bool SerializeSingleStructOption(
template <typename T> template <typename T>
Status GetStringFromStruct( Status GetStringFromStruct(
std::string* opt_string, const T& options, std::string* opt_string, const T& options,
const std::unordered_map<std::string, OptionTypeInfo> type_info, const std::unordered_map<std::string, OptionTypeInfo>& type_info,
const std::string& delimiter) { const std::string& delimiter) {
assert(opt_string); assert(opt_string);
opt_string->clear(); opt_string->clear();

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