Merge pull request #3367 from yandex/CLICKHOUSE-4060

CLICKHOUSE-4060: Use individual context for each function

dbms/src/Interpreters/ExpressionJIT.cpp

@@ -705,8 +705,6 @@ void compileFunctions(ExpressionActions::Actions & actions, const Names & output
     static LLVMTargetInitializer initializer;
 
     auto dependents = getActionsDependents(actions, output_columns);
-    /// Initialize context as late as possible and only if needed
-    std::shared_ptr<LLVMContext> context;
     std::vector<ExpressionActions::Actions> fused(actions.size());
     for (size_t i = 0; i < actions.size(); ++i)
     {
@@ -722,7 +720,7 @@ void compileFunctions(ExpressionActions::Actions & actions, const Names & output
 
             auto hash_key = ExpressionActions::ActionsHash{}(fused[i]);
             {
-                std::lock_guard<std::mutex> lock(mutex);
+                std::lock_guard lock(mutex);
                 if (counter[hash_key]++ < min_count_to_compile)
                     continue;
             }
@@ -730,26 +728,24 @@ void compileFunctions(ExpressionActions::Actions & actions, const Names & output
             std::shared_ptr<LLVMFunction> fn;
             if (compilation_cache)
             {
-                /// Lock here, to be sure, that all functions will be compiled
+                std::tie(fn, std::ignore) = compilation_cache->getOrSet(hash_key, [&inlined_func=std::as_const(fused[i]), &sample_block] ()
-                std::lock_guard<std::mutex> lock(mutex);
-                /// Don't use getOrSet here, because sometimes we need to initialize context
-                fn = compilation_cache->get(hash_key);
-                if (!fn)
                 {
-                    if (!context)
-                        context = std::make_shared<LLVMContext>();
                     Stopwatch watch;
-                    fn = std::make_shared<LLVMFunction>(fused[i], context, sample_block);
+                    std::shared_ptr<LLVMContext> context = std::make_shared<LLVMContext>();
+                    auto result_fn = std::make_shared<LLVMFunction>(inlined_func, context, sample_block);
+                    size_t used_memory = context->compileAllFunctionsToNativeCode();
+                    ProfileEvents::increment(ProfileEvents::CompileExpressionsBytes, used_memory);
                     ProfileEvents::increment(ProfileEvents::CompileExpressionsMicroseconds, watch.elapsedMicroseconds());
-                    compilation_cache->set(hash_key, fn);
+                    return result_fn;
-                }
+                });
             }
             else
             {
-                if (!context)
+                std::shared_ptr<LLVMContext> context = std::make_shared<LLVMContext>();
-                    context = std::make_shared<LLVMContext>();
                 Stopwatch watch;
                 fn = std::make_shared<LLVMFunction>(fused[i], context, sample_block);
+                size_t used_memory = context->compileAllFunctionsToNativeCode();
+                ProfileEvents::increment(ProfileEvents::CompileExpressionsBytes, used_memory);
                 ProfileEvents::increment(ProfileEvents::CompileExpressionsMicroseconds, watch.elapsedMicroseconds());
             }
 
@@ -765,22 +761,12 @@ void compileFunctions(ExpressionActions::Actions & actions, const Names & output
             fused[*dep].insert(fused[*dep].end(), fused[i].begin(), fused[i].end());
     }
 
-    if (context)
-    {
-        /// Lock here, because other threads can get uncompilted functions from cache
-        std::lock_guard<std::mutex> lock(mutex);
-        size_t used_memory = context->compileAllFunctionsToNativeCode();
-        ProfileEvents::increment(ProfileEvents::CompileExpressionsBytes, used_memory);
-    }
-
     for (size_t i = 0; i < actions.size(); ++i)
     {
         if (actions[i].type == ExpressionAction::APPLY_FUNCTION && actions[i].is_function_compiled)
-        {
             actions[i].function = actions[i].function_base->prepare({}, {}, 0); /// Arguments are not used for LLVMFunction.
     }
 }
-}
 
 }
 

dbms/src/Interpreters/Settings.h

@@ -74,7 +74,7 @@ struct Settings
     M(SettingFloat, totals_auto_threshold, 0.5, "The threshold for totals_mode = 'auto'.") \
     \
     M(SettingBool, compile, false, "Whether query compilation is enabled.") \
-    M(SettingBool, compile_expressions, false, "Compile some scalar functions and operators to native code.") \
+    M(SettingBool, compile_expressions, true, "Compile some scalar functions and operators to native code.") \
     M(SettingUInt64, min_count_to_compile, 3, "The number of structurally identical queries before they are compiled.") \
     M(SettingUInt64, group_by_two_level_threshold, 100000, "From what number of keys, a two-level aggregation starts. 0 - the threshold is not set.") \
     M(SettingUInt64, group_by_two_level_threshold_bytes, 100000000, "From what size of the aggregation state in bytes, a two-level aggregation begins to be used. 0 - the threshold is not set. Two-level aggregation is used when at least one of the thresholds is triggered.") \