From 39d598bd90dfd38c26f39ad62fd987677b0c5d6c Mon Sep 17 00:00:00 2001
From: Lin Ma <malin1993ml@gmail.com>
Date: Mon, 7 Jun 2021 16:50:28 -0400
Subject: [PATCH] Enable changing the compiled_query_execution setting at
 runtime (#1609)

---
 src/include/settings/settings_callbacks.h |  4 ++++
 src/include/settings/settings_defs.h      |  4 ++--
 src/include/traffic_cop/traffic_cop.h     | 10 +++++++++-
 src/settings/settings_callbacks.cpp       |  8 ++++++++
 4 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/include/settings/settings_callbacks.h b/src/include/settings/settings_callbacks.h
index cdf095e930..eb4ca7b980 100644
--- a/src/include/settings/settings_callbacks.h
+++ b/src/include/settings/settings_callbacks.h
@@ -96,6 +96,10 @@ class Callbacks {
   static void MetricsQueryTraceOutput(void *old_value, void *new_value, DBMain *db_main,
                                       common::ManagedPointer<common::ActionContext> action_context);
 
+  /** Update the query execution mode in TrafficCop */
+  static void CompiledQueryExecution(void *old_value, void *new_value, DBMain *db_main,
+                                     common::ManagedPointer<common::ActionContext> action_context);
+
   /** Set the forecast sample limit. */
   static void ForecastSampleLimit(void *old_value, void *new_value, DBMain *db_main,
                                   common::ManagedPointer<common::ActionContext> action_context);
diff --git a/src/include/settings/settings_defs.h b/src/include/settings/settings_defs.h
index 9693be5e80..3344b58da3 100644
--- a/src/include/settings/settings_defs.h
+++ b/src/include/settings/settings_defs.h
@@ -409,8 +409,8 @@ SETTING_bool(
     compiled_query_execution,
     "Compile queries to native machine code using LLVM, rather than relying on TPL interpretation (default: false).",
     false,
-    false,
-    noisepage::settings::Callbacks::NoOp
+    true,
+    noisepage::settings::Callbacks::CompiledQueryExecution
 )
 
 SETTING_string(
diff --git a/src/include/traffic_cop/traffic_cop.h b/src/include/traffic_cop/traffic_cop.h
index 3698800879..f5fd70b67f 100644
--- a/src/include/traffic_cop/traffic_cop.h
+++ b/src/include/traffic_cop/traffic_cop.h
@@ -260,6 +260,14 @@ class TrafficCop {
    */
   void SetOptimizerTimeout(const uint64_t optimizer_timeout) { optimizer_timeout_ = optimizer_timeout; }
 
+  /**
+   * Adjust the TrafficCop's execution mode value (for use by SettingsManager)
+   * @param is_compiled set execution_mode_ to Compiled if true; Interpret if false
+   */
+  void SetExecutionMode(bool is_compiled) {
+    execution_mode_ = is_compiled ? execution::vm::ExecutionMode::Compiled : execution::vm::ExecutionMode::Interpret;
+  }
+
   /**
    * @return true if query caching enabled, false otherwise
    */
@@ -274,7 +282,7 @@ class TrafficCop {
   common::ManagedPointer<optimizer::StatsStorage> stats_storage_;
   uint64_t optimizer_timeout_;
   const bool use_query_cache_;
-  const execution::vm::ExecutionMode execution_mode_;
+  execution::vm::ExecutionMode execution_mode_;
 };
 
 }  // namespace noisepage::trafficcop
diff --git a/src/settings/settings_callbacks.cpp b/src/settings/settings_callbacks.cpp
index 5c88086747..8eeb4e01e7 100644
--- a/src/settings/settings_callbacks.cpp
+++ b/src/settings/settings_callbacks.cpp
@@ -186,6 +186,14 @@ void Callbacks::MetricsQueryTraceOutput(void *const old_value, void *const new_v
   action_context->SetState(common::ActionState::SUCCESS);
 }
 
+void Callbacks::CompiledQueryExecution(void *const old_value, void *const new_value, DBMain *const db_main,
+                                       common::ManagedPointer<common::ActionContext> action_context) {
+  action_context->SetState(common::ActionState::IN_PROGRESS);
+  bool is_compiled = *static_cast<bool *>(new_value);
+  db_main->GetTrafficCop()->SetExecutionMode(is_compiled);
+  action_context->SetState(common::ActionState::SUCCESS);
+}
+
 void Callbacks::ForecastSampleLimit(void *old_value, void *new_value, DBMain *db_main,
                                     common::ManagedPointer<common::ActionContext> action_context) {
   action_context->SetState(common::ActionState::IN_PROGRESS);