From f740cf4eaa71621fb518c6d5668e8356f452a979 Mon Sep 17 00:00:00 2001
From: Antonio Andelic <antonio@clickhouse.com>
Date: Wed, 14 Aug 2024 09:54:03 +0200
Subject: [PATCH] Fix data race on SampleKey

---
 src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp b/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp
index a6ef0063069..6efd3a5c97f 100644
--- a/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp
+++ b/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp
@@ -369,7 +369,7 @@ MergeTreeDataSelectSamplingData MergeTreeDataSelectExecutor::getSampling(
             /// If sample and final are used together no need to calculate sampling expression twice.
             /// The first time it was calculated for final, because sample key is a part of the PK.
             /// So, assume that we already have calculated column.
-            ASTPtr sampling_key_ast = metadata_snapshot->getSamplingKeyAST();
+            ASTPtr sampling_key_ast;
 
             if (final)
             {
@@ -377,6 +377,12 @@ MergeTreeDataSelectSamplingData MergeTreeDataSelectExecutor::getSampling(
                 /// We do spoil available_real_columns here, but it is not used later.
                 available_real_columns.emplace_back(sampling_key.column_names[0], std::move(sampling_column_type));
             }
+            else
+            {
+                sampling_key_ast = metadata_snapshot->getSamplingKeyAST()->clone();
+            }
+
+            chassert(sampling_key_ast != nullptr);
 
             if (has_lower_limit)
             {