Properly check the limit for sleepEachRow function. Add a setting function_sleep_max_microseconds_per_block

src/Core/Settings.h

@@ -633,7 +633,8 @@ class IColumn;
     M(UInt64, limit, 0, "Limit on read rows from the most 'end' result for select query, default 0 means no limit length", 0) \
     M(UInt64, offset, 0, "Offset on read rows from the most 'end' result for select query", 0) \
     \
-    M(UInt64, function_range_max_elements_in_block, 500000000, "Maximum number of values generated by function 'range' per block of data (sum of array sizes for every row in a block, see also 'max_block_size' and 'min_insert_block_size_rows'). It is a safety threshold.", 0) \
+    M(UInt64, function_range_max_elements_in_block, 500000000, "Maximum number of values generated by function `range` per block of data (sum of array sizes for every row in a block, see also 'max_block_size' and 'min_insert_block_size_rows'). It is a safety threshold.", 0) \
+    M(UInt64, function_sleep_max_microseconds_per_block, 3000, "Maximum number of microseconds the function `sleep` is allowed to sleep for each block. If a user called it with a larger value, it throws an exception. It is a safety threshold.", 0) \
     M(ShortCircuitFunctionEvaluation, short_circuit_function_evaluation, ShortCircuitFunctionEvaluation::ENABLE, "Setting for short-circuit function evaluation configuration. Possible values: 'enable' - use short-circuit function evaluation for functions that are suitable for it, 'disable' - disable short-circuit function evaluation, 'force_enable' - use short-circuit function evaluation for all functions.", 0) \
     \
     M(LocalFSReadMethod, storage_file_read_method, LocalFSReadMethod::mmap, "Method of reading data from storage file, one of: read, pread, mmap.", 0) \

src/Functions/sleep.h

@@ -9,7 +9,8 @@
 #include <Common/assert_cast.h>
 #include <base/sleep.h>
 #include <IO/WriteHelpers.h>
-#include <Interpreters/Context_fwd.h>
+#include <Interpreters/Context.h>
+
 
 namespace ProfileEvents
 {
@@ -40,11 +41,17 @@ enum class FunctionSleepVariant
 template <FunctionSleepVariant variant>
 class FunctionSleep : public IFunction
 {
+private:
+    UInt64 max_microseconds;
 public:
     static constexpr auto name = variant == FunctionSleepVariant::PerBlock ? "sleep" : "sleepEachRow";
-    static FunctionPtr create(ContextPtr)
+    static FunctionPtr create(ContextPtr context)
+    {
+        return std::make_shared<FunctionSleep<variant>>(context->getSettingsRef().function_sleep_max_microseconds_per_block);
+    }
+
+    FunctionSleep(UInt64 max_microseconds_) : max_microseconds(max_microseconds_)
     {
-        return std::make_shared<FunctionSleep<variant>>();
     }
 
     /// Get the name of the function.
@@ -105,13 +112,19 @@ public:
         if (size > 0)
         {
             /// When sleeping, the query cannot be cancelled. For ability to cancel query, we limit sleep time.
-            if (seconds > 3.0)   /// The choice is arbitrary
+            if (seconds * 1e6 > max_microseconds)
                 throw Exception(ErrorCodes::TOO_SLOW, "The maximum sleep time is 3 seconds. Requested: {}", toString(seconds));
 
             if (!dry_run)
             {
                 UInt64 count = (variant == FunctionSleepVariant::PerBlock ? 1 : size);
                 UInt64 microseconds = static_cast<UInt64>(seconds * count * 1e6);
+
+                if (microseconds > max_microseconds)
+                    throw Exception(ErrorCodes::TOO_SLOW,
+                        "The maximum sleep time is 3 seconds. Requested: {} microseconds per block (of size {})",
+                        microseconds, size);
+
                 sleepForMicroseconds(microseconds);
                 ProfileEvents::increment(ProfileEvents::SleepFunctionCalls, count);
                 ProfileEvents::increment(ProfileEvents::SleepFunctionMicroseconds, microseconds);

tests/queries/0_stateless/02725_sleep_max_time.sql

@@ -0,0 +1 @@
+SELECT * FROM system.numbers WHERE sleepEachRow(0.05) LIMIT 10; -- { serverError TOO_SLOW }