Fix parallel replicas in presense of a scalar subquery with a big integer value

src/Common/FieldVisitorToString.cpp

@@ -18,16 +18,37 @@ template <typename T>
 static inline String formatQuoted(T x)
 {
     WriteBufferFromOwnString wb;
-    writeQuoted(x, wb);
-    return wb.str();
-}
 
-template <typename T>
-static inline void writeQuoted(const DecimalField<T> & x, WriteBuffer & buf)
-{
-    writeChar('\'', buf);
-    writeText(x.getValue(), x.getScale(), buf, {});
-    writeChar('\'', buf);
+    if constexpr (is_decimal_field<T>)
+    {
+        writeChar('\'', wb);
+        writeText(x.getValue(), x.getScale(), wb, {});
+        writeChar('\'', wb);
+    }
+    else if constexpr (is_big_int_v<T>)
+    {
+        writeChar('\'', wb);
+        writeText(x, wb);
+        writeChar('\'', wb);
+    }
+    else
+    {
+        /// While `writeQuoted` sounds like it will always write the value in quotes,
+        /// in fact it means: write according to the rules of the quoted format, like VALUES,
+        /// where strings, dates, date-times, UUID are in quotes, and numbers are not.
+
+        /// That's why we take extra care to put Decimal and big integers inside quotes
+        /// when formatting literals in SQL language,
+        /// because it is different from the quoted formats like VALUES.
+
+        /// In fact, there are no Decimal and big integer literals in SQL,
+        /// but they can appear if we format the query from a modified AST.
+
+        /// We can fix this idiosyncrasy later.
+
+        writeQuoted(x, wb);
+    }
+    return wb.str();
 }
 
 /** In contrast to writeFloatText (and writeQuoted),

tests/queries/0_stateless/02949_parallel_replicas_scalar_subquery_big_integer.reference

@@ -0,0 +1 @@
+6	111111111111111111111111111111111111111

tests/queries/0_stateless/02949_parallel_replicas_scalar_subquery_big_integer.sql

@@ -0,0 +1,9 @@
+DROP TABLE IF EXISTS test;
+CREATE TABLE test (x UInt8) ENGINE = MergeTree ORDER BY x;
+INSERT INTO test VALUES (1), (2), (3);
+
+SET allow_experimental_parallel_reading_from_replicas = 1, max_parallel_replicas = 2, cluster_for_parallel_replicas = 'test_cluster_one_shard_three_replicas_localhost', prefer_localhost_replica = 0, parallel_replicas_for_non_replicated_merge_tree = 1;
+
+WITH (SELECT '111111111111111111111111111111111111111'::UInt128) AS v SELECT sum(x), max(v) FROM test;
+
+DROP TABLE test;