Merge pull request ClickHouse#79964 from Algunenano/disable_cpu_overload

Disable connections and queries drop by default

Author: Algunenano

src/Common/ProfileEvents.cpp

@@ -1135,6 +1135,8 @@ Event end() { return END; }
 
 bool checkCPUOverload(Int64 os_cpu_busy_time_threshold, double min_ratio, double max_ratio, bool should_throw)
 {
+    if ((max_ratio <= 0.0) || (max_ratio <= min_ratio))
+        return false;
     double cpu_load = global_counters.getCPUOverload(os_cpu_busy_time_threshold);
 
     if (cpu_load > DBL_EPSILON)

src/Core/Settings.cpp

@@ -6510,8 +6510,8 @@ File/S3 engines/table function will parse paths with '::' as `<archive> :: <file
     DECLARE(Milliseconds, low_priority_query_wait_time_ms, 1000, R"(
 When the query prioritization mechanism is employed (see setting `priority`), low-priority queries wait for higher-priority queries to finish. This setting specifies the duration of waiting.
 )", BETA) \
-    DECLARE(Float, min_os_cpu_wait_time_ratio_to_throw, 2.0, "Min ratio between OS CPU wait (OSCPUWaitMicroseconds metric) and busy (OSCPUVirtualTimeMicroseconds metric) times to consider rejecting queries. Linear interpolation between min and max ratio is used to calculate the probability, the probability is 0 at this point.", 0) \
-    DECLARE(Float, max_os_cpu_wait_time_ratio_to_throw, 6.0, "Max ratio between OS CPU wait (OSCPUWaitMicroseconds metric) and busy (OSCPUVirtualTimeMicroseconds metric) times to consider rejecting queries. Linear interpolation between min and max ratio is used to calculate the probability, the probability is 1 at this point.", 0) \
+    DECLARE(Float, min_os_cpu_wait_time_ratio_to_throw, 0.0, "Min ratio between OS CPU wait (OSCPUWaitMicroseconds metric) and busy (OSCPUVirtualTimeMicroseconds metric) times to consider rejecting queries. Linear interpolation between min and max ratio is used to calculate the probability, the probability is 0 at this point.", 0) \
+    DECLARE(Float, max_os_cpu_wait_time_ratio_to_throw, 0.0, "Max ratio between OS CPU wait (OSCPUWaitMicroseconds metric) and busy (OSCPUVirtualTimeMicroseconds metric) times to consider rejecting queries. Linear interpolation between min and max ratio is used to calculate the probability, the probability is 1 at this point.", 0) \
     \
     /* ####################################################### */ \
     /* ########### START OF EXPERIMENTAL FEATURES ############ */ \

src/Core/SettingsChangesHistory.cpp

@@ -78,6 +78,8 @@ const VersionToSettingsChangesMap & getSettingsChangesHistory()
             {"page_cache_lookahead_blocks", 16, 16, "Made this setting adjustable on a per-query level."},
             {"output_format_pretty_glue_chunks", "0", "auto", "A new setting to make Pretty formats prettier."},
             {"parallel_hash_join_threshold", 0, 100'000, "New setting"},
+            {"min_os_cpu_wait_time_ratio_to_throw", 0, 0, "Setting values were changed and backported to 25.4"},
+            {"max_os_cpu_wait_time_ratio_to_throw", 0, 0, "Setting values were changed and backported to 25.4"},
             {"make_distributed_plan", 0, 0, "New experimental setting."},
             {"execute_distributed_plan_locally", 0, 0, "New experimental setting."},
             {"default_shuffle_join_bucket_count", 8, 8, "New experimental setting."},
@@ -105,8 +107,8 @@ const VersionToSettingsChangesMap & getSettingsChangesHistory()
             {"cast_string_to_variant_use_inference", true, true, "New setting to enable/disable types inference during CAST from String to Variant"},
             {"distributed_cache_read_request_max_tries", 20, 20, "New setting"},
             {"query_condition_cache_store_conditions_as_plaintext", false, false, "New setting"},
-            {"min_os_cpu_wait_time_ratio_to_throw", 0, 2, "New setting"},
-            {"max_os_cpu_wait_time_ratio_to_throw", 0, 6, "New setting"},
+            {"min_os_cpu_wait_time_ratio_to_throw", 0, 0, "New setting"},
+            {"max_os_cpu_wait_time_ratio_to_throw", 0, 0, "New setting"},
             {"query_plan_merge_filter_into_join_condition", false, true, "Added new setting to merge filter into join condition"},
             {"use_local_cache_for_remote_storage", true, false, "Obsolete setting."},
             {"iceberg_timestamp_ms", 0, 0, "New setting."},