From c5a2f3aafbe6373a662f80f715e56a302a7fdd8b Mon Sep 17 00:00:00 2001
From: Igor Nikonov <igor@clickhouse.com>
Date: Thu, 1 Aug 2024 14:21:54 +0000
Subject: [PATCH] Limit min_marks_for_concurrent_read

---
 src/Processors/QueryPlan/ReadFromMergeTree.cpp | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/Processors/QueryPlan/ReadFromMergeTree.cpp b/src/Processors/QueryPlan/ReadFromMergeTree.cpp
index 772bf427892..ec64db4139f 100644
--- a/src/Processors/QueryPlan/ReadFromMergeTree.cpp
+++ b/src/Processors/QueryPlan/ReadFromMergeTree.cpp
@@ -383,9 +383,12 @@ Pipe ReadFromMergeTree::readFromPoolParallelReplicas(RangesInDataParts parts_wit
     /// We have a special logic for local replica. It has to read less data, because in some cases it should
     /// merge states of aggregate functions or do some other important stuff other than reading from Disk.
     auto multiplier = context->getSettingsRef().parallel_replicas_single_task_marks_count_multiplier;
-    // avoid using multiplier if min marks to read is already too big (to avoid overflow)
-    if (pool_settings.min_marks_for_concurrent_read >= std::numeric_limits<Int64>::max())
+    if (pool_settings.min_marks_for_concurrent_read > std::numeric_limits<Int64>::max())
+    {
+        /// limit min marks to read in case it's big, happened in test since due to settings randomzation
+        pool_settings.min_marks_for_concurrent_read = std::numeric_limits<Int64>::max();
         multiplier = 1.0f;
+    }
 
     if (auto result = pool_settings.min_marks_for_concurrent_read * multiplier; canConvertTo<size_t>(result))
         pool_settings.min_marks_for_concurrent_read = static_cast<size_t>(result);
@@ -556,9 +559,12 @@ Pipe ReadFromMergeTree::readInOrder(
         };
 
         auto multiplier = context->getSettingsRef().parallel_replicas_single_task_marks_count_multiplier;
-        // avoid using multiplier if min marks to read is already too big (to avoid overflow)
-        if (pool_settings.min_marks_for_concurrent_read >= std::numeric_limits<Int64>::max())
+        if (pool_settings.min_marks_for_concurrent_read > std::numeric_limits<Int64>::max())
+        {
+            /// limit min marks to read in case it's big, happened in test since due to settings randomzation
+            pool_settings.min_marks_for_concurrent_read = std::numeric_limits<Int64>::max();
             multiplier = 1.0f;
+        }
 
         if (auto result = pool_settings.min_marks_for_concurrent_read * multiplier; canConvertTo<size_t>(result))
             pool_settings.min_marks_for_concurrent_read = static_cast<size_t>(result);