Fix some PVS-Studio warnings

src/Common/Volnitsky.h

@@ -303,7 +303,7 @@ namespace VolnitskyTraits
                     {
                         /// ngram for Ul
                         chars.c0 = c0u;
-                        chars.c1 = c1l;
+                        chars.c1 = c1l; //-V1048
                         putNGramBase(n, offset);
                     }
 

src/Core/SettingsQuirks.cpp

@@ -4,9 +4,7 @@
 
 #ifdef __linux__
 #include <linux/version.h>
-#endif
 
-#ifdef __linux__
 /// Detect does epoll_wait with nested epoll fds works correctly.
 /// Polling nested epoll fds from epoll_wait is required for async_socket_for_remote and use_hedged_requests.
 ///
@@ -16,21 +14,15 @@
 ///   [2]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0c54a6a44bf3
 bool nestedEpollWorks(Poco::Logger * log)
 {
-    bool nested_epoll_works =
 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5, 5, 0)) && (LINUX_VERSION_CODE < KERNEL_VERSION(5, 6, 13))
         /// the check is correct since there will be no more 5.5.x releases.
-        false
-#else
-        true
-#endif
-    ;
-
-    if (!nested_epoll_works)
-    {
         if (log)
             LOG_WARNING(log, "Nested epoll_wait has some issues on kernels [5.5.0, 5.6.13). You should upgrade it to avoid possible issues.");
-    }
+        return false;
-    return nested_epoll_works;
+#else
+        (void)log;
+        return true;
+#endif
 }
 #else
 bool nestedEpollWorks(Poco::Logger *) { return true; }

src/DataStreams/PushingToViewsBlockOutputStream.cpp

@@ -63,7 +63,7 @@ PushingToViewsBlockOutputStream::PushingToViewsBlockOutputStream(
 
         // Do not deduplicate insertions into MV if the main insertion is Ok
         if (disable_deduplication_for_children)
-            insert_context->setSetting("insert_deduplicate", false);
+            insert_context->setSetting("insert_deduplicate", Field{false});
 
         // Separate min_insert_block_size_rows/min_insert_block_size_bytes for children
         if (insert_settings.min_insert_block_size_rows_for_materialized_views)

src/DataTypes/Serializations/SerializationLowCardinality.cpp

@@ -160,7 +160,7 @@ struct IndexesSerializationType
             return std::make_shared<DataTypeUInt16>();
         if (type == TUInt32)
             return std::make_shared<DataTypeUInt32>();
-        if (type == TUInt64)
+        if (type == TUInt64) //-V547
             return std::make_shared<DataTypeUInt64>();
 
         throw Exception("Can't create DataType from IndexesSerializationType.", ErrorCodes::LOGICAL_ERROR);

src/Interpreters/ActionsVisitor.cpp

@@ -207,7 +207,7 @@ static Block createBlockFromAST(const ASTPtr & node, const DataTypes & types, Co
 
             assert(tuple || func);
 
-            size_t tuple_size = tuple ? tuple->size() : func->arguments->children.size();
+            size_t tuple_size = tuple ? tuple->size() : func->arguments->children.size(); //-V1004
             if (tuple_size != num_columns)
                 throw Exception("Incorrect size of tuple in set: " + toString(tuple_size) + " instead of " + toString(num_columns),
                     ErrorCodes::INCORRECT_ELEMENT_OF_SET);

src/Interpreters/ProcessList.h

@@ -276,7 +276,7 @@ protected:
 
     /// List of queries
     Container processes;
-    size_t max_size;        /// 0 means no limit. Otherwise, when limit exceeded, an exception is thrown.
+    size_t max_size = 0;        /// 0 means no limit. Otherwise, when limit exceeded, an exception is thrown.
 
     /// Stores per-user info: queries, statistics and limits
     UserToQueries user_to_queries;