Do not generate error messages in TRY_CAST and TRY(CAST) (facebookinc…

…ubator#9900)

Summary:
Pull Request resolved: facebookincubator#9900

Generating error messages and carrying them around is quite expensive. Since we
don't use error messages in TRY_CAST or TRY(CAST) we can avoid generating them
altogether. Doing so improves performance up to 3x.

Introduce thread-local flag to indicate whether no-throw APIs need to provide
detailed error message. Use this flag to avoid generating error messages in CAST.

try_cast_invalid_nan benchmark improved 3x:

Before:

```
============================================================================
[...]hmarks/ExpressionBenchmarkBuilder.cpp     relative  time/iter   iters/s
============================================================================
cast##try_cast_invalid_empty_input                          2.21ms    452.57
cast##tryexpr_cast_invalid_empty_input                     24.23ms     41.27
cast##try_cast_invalid_nan                                 16.95ms     59.00
cast##tryexpr_cast_invalid_nan                             42.26ms     23.66
----------------------------------------------------------------------------
```

After:

```
============================================================================
[...]hmarks/ExpressionBenchmarkBuilder.cpp     relative  time/iter   iters/s
============================================================================
cast##try_cast_invalid_empty_input                          2.41ms    415.65
cast##tryexpr_cast_invalid_empty_input                     24.90ms     40.16
cast##try_cast_invalid_nan                                  5.76ms    173.52
cast##tryexpr_cast_invalid_nan                             27.75ms     36.03
```

Reviewed By: xiaoxmeng, Yuhta

Differential Revision: D57700900

fbshipit-source-id: c95b293986f2f293a33e199725ca5c50c84e415e

velox/common/base/VeloxException.cpp

@@ -38,6 +38,11 @@ int64_t& threadNumVeloxThrow() {
   return numThrow;
 }
 
+bool& threadSkipErrorDetails() {
+  thread_local bool skipErrorDetails{false};
+  return skipErrorDetails;
+}
+
 ExceptionContext& getExceptionContext() {
   thread_local ExceptionContext context;
   return context;

velox/common/base/VeloxException.h

@@ -341,6 +341,25 @@ class VeloxRuntimeError final : public VeloxException {
 /// Returns a reference to a thread level counter of Velox error throws.
 int64_t& threadNumVeloxThrow();
 
+/// Returns a reference to a thread level boolean that controls whether no-throw
+/// APIs include detailed error messages in Status.
+bool& threadSkipErrorDetails();
+
+class ScopedThreadSkipErrorDetails {
+ public:
+  ScopedThreadSkipErrorDetails(bool skip = true)
+      : original_{threadSkipErrorDetails()} {
+    threadSkipErrorDetails() = skip;
+  }
+
+  ~ScopedThreadSkipErrorDetails() {
+    threadSkipErrorDetails() = original_;
+  }
+
+ private:
+  bool original_;
+};
+
 /// Holds a pointer to a function that provides addition context to be
 /// added to the detailed error message in case of an exception.
 struct ExceptionContext {

velox/expression/CastExpr.cpp

@@ -920,6 +920,9 @@ void CastExpr::evalSpecialForm(
     ScopedVarSetter holder{context.mutableThrowOnError(), false};
     ScopedVarSetter captureErrorDetails(
         context.mutableCaptureErrorDetails(), false);
+
+    ScopedThreadSkipErrorDetails skipErrorDetails(true);
+
     apply(rows, input, context, fromType, toType, result);
   } else {
     apply(rows, input, context, fromType, toType, result);

velox/expression/TryExpr.cpp

@@ -26,6 +26,8 @@ void TryExpr::evalSpecialForm(
   ScopedVarSetter captureErrorDetails(
       context.mutableCaptureErrorDetails(), false);
 
+  ScopedThreadSkipErrorDetails skipErrorDetails(true);
+
   // It's possible with nested TRY expressions that some rows already threw
   // exceptions in earlier expressions that haven't been handled yet. To avoid
   // incorrectly handling them here, store those errors and temporarily reset
@@ -48,6 +50,8 @@ void TryExpr::evalSpecialFormSimplified(
   ScopedVarSetter captureErrorDetails(
       context.mutableCaptureErrorDetails(), false);
 
+  ScopedThreadSkipErrorDetails skipErrorDetails(true);
+
   // It's possible with nested TRY expressions that some rows already threw
   // exceptions in earlier expressions that haven't been handled yet. To avoid
   // incorrectly handling them here, store those errors and temporarily reset

velox/type/Conversions.h

@@ -70,6 +70,9 @@ template <typename T, typename F>
 Expected<T> callFollyTo(const F& v) {
   const auto result = folly::tryTo<T>(v);
   if (result.hasError()) {
+    if (threadSkipErrorDetails()) {
+      return folly::makeUnexpected(Status::UserError(""));
+    }
     return folly::makeUnexpected(Status::UserError(
         "{}", folly::makeConversionError(result.error(), "").what()));
   }