check that sharding_key exists in the table and has numeric type (#392)

* check that sharding_key exists in the table and has numeric type [#CLICKHOUSE-2191]

* style

* infer type of sharding expression [#CLICKHOUSE-2191]

dbms/src/Storages/Distributed/DistributedBlockOutputStream.cpp

@@ -66,12 +66,11 @@ std::vector<IColumn::Filter> DistributedBlockOutputStream::createFilters(Block b
 	/// check that key column has valid type
 	const auto it = creators.find(key_column.type->getName());
 
-	return it != std::end(creators)
-		? (*it->second)(block.rows(), key_column.column.get(), *cluster)
-		: throw Exception{
-			"Sharding key expression does not evaluate to an integer type",
-			ErrorCodes::TYPE_MISMATCH
-		};
+	if (it == std::end(creators))
+		throw Exception{"Sharding key expression does not evaluate to an integer type",
+			ErrorCodes::TYPE_MISMATCH};
+
+	return (*it->second)(block.rows(), key_column.column.get(), *cluster);
 }
 
 void DistributedBlockOutputStream::writeSplit(const Block & block)

dbms/src/Storages/StorageFactory.cpp

@@ -5,11 +5,13 @@
 #include <DB/Common/StringUtils.h>
 
 #include <DB/Parsers/ASTCreateQuery.h>
+#include <DB/Parsers/ASTFunction.h>
 #include <DB/Parsers/ASTIdentifier.h>
 #include <DB/Parsers/ASTLiteral.h>
 
 #include <DB/Interpreters/Context.h>
 #include <DB/Interpreters/evaluateConstantExpression.h>
+#include <DB/Interpreters/ExpressionAnalyzer.h>
 #include <DB/Interpreters/getClusterName.h>
 
 #include <DB/Storages/StorageLog.h>
@@ -49,6 +51,7 @@ namespace ErrorCodes
 	extern const int UNKNOWN_ELEMENT_IN_CONFIG;
 	extern const int UNKNOWN_IDENTIFIER;
 	extern const int FUNCTION_CANNOT_HAVE_PARAMETERS;
+	extern const int TYPE_MISMATCH;
 }
 
 
@@ -464,6 +467,22 @@ StoragePtr StorageFactory::get(
 
 		const auto & sharding_key = args.size() == 4 ? args[3] : nullptr;
 
+		/// Check that sharding_key exists in the table and has numeric type.
+		if (sharding_key)
+		{
+			auto sharding_expr = ExpressionAnalyzer(sharding_key, context, nullptr, *columns).getActions(false);
+			const Block & block = sharding_expr->getSampleBlock();
+
+			if (block.columns() != 0)
+			{
+				auto type = block.getColumns().back().type;
+
+				if (!type->isNumeric())
+					throw Exception("Sharding expression has type " + type->getName() +
+									", but should be one of integer type", ErrorCodes::TYPE_MISMATCH);
+			}
+		}
+
 		return StorageDistributed::create(
 			table_name, columns,
 			materialized_columns, alias_columns, column_defaults,