Handle enums with too many values (#366)

* Handle enums with too many values

* add log info message

* Change limit calculation

mysql-test/mytile/r/enum.result

@@ -53,3 +53,14 @@ select `dim1`, `attr1`, `fruit` from tiledb_with_enum where fruit = 'pear';
 dim1	attr1	fruit
 1	2	pear
 DROP TABLE tiledb_with_enum;
+# Test enum with too many values. Reverts to non-enum. Affected attribute `gene_symbol`
+CREATE TABLE var ENGINE=mytile uri='MTR_SUITE_DIR/test_data/tabula-sapiens-immune-var';;
+describe var;
+Field	Type	Null	Key	Default	Extra
+soma_joinid	bigint(20)	NO	PRI	NULL	
+ensemblid	text	NO		NULL	
+feature_type	enum('Gene Expression')	NO		NULL	
+gene_symbol	int(11)	NO		NULL	
+var_id	text	NO		NULL	
+SET mytile_delete_arrays=0;
+DROP TABLE var;

mysql-test/mytile/t/enum.test

@@ -30,4 +30,11 @@ WHERE table_name = 'tiledb_with_enum' order by column_name;
 
 select `dim1`, `attr1`, `fruit` from tiledb_with_enum order by `dim1`;
 select `dim1`, `attr1`, `fruit` from tiledb_with_enum where fruit = 'pear';
-DROP TABLE tiledb_with_enum;
+DROP TABLE tiledb_with_enum;
+
+--echo # Test enum with too many values. Reverts to non-enum. Affected attribute `gene_symbol`
+--replace_result $MTR_SUITE_DIR MTR_SUITE_DIR
+--eval CREATE TABLE var ENGINE=mytile uri='$MTR_SUITE_DIR/test_data/tabula-sapiens-immune-var';
+describe var;
+SET mytile_delete_arrays=0;
+DROP TABLE var;

mytile/mytile-discovery.cc

@@ -324,33 +324,55 @@ int tile::discover_array(THD *thd, TABLE_SHARE *ts, HA_CREATE_INFO *info) {
           TileDBTypeToMysqlType(attribute.type(), attribute.cell_size() > 1,
                                 attribute.cell_val_num());
 
+      // Handle enums
+      size_t enum_values = 0;
+      std::stringstream enum_string;
+      bool empty_enum = false;
+      // first we need to see if the enum values are too many
+
       if (is_enum) {
-        // if the attribute has an enum
+        // if the attribute has an enum calculate enum values
         auto enmr = tiledb::ArrayExperimental::get_enumeration(
             ctx, array, enmr_name.value());
 
         auto enum_vec_string = enmr.as_vector<std::string>();
+        // store enum values
+        enum_values = enum_vec_string.size();
+
+        if (enum_vec_string.size() == 0) {
+          empty_enum = true;
+        }
 
-        if (enum_vec_string.size() != 0) {
-          sql_string << "ENUM"
-                     << "(";
-          for (size_t i = 0; i < enum_vec_string.size(); ++i) {
-            sql_string << "'" << enum_vec_string[i] << "'";
-            if (i < enum_vec_string.size() - 1) {
-              sql_string << ", ";
-            }
+        enum_string << "ENUM" << "(";
+        for (size_t i = 0; i < enum_vec_string.size(); ++i) {
+          enum_string << "'" << enum_vec_string[i] << "'";
+          if (i < enum_vec_string.size() - 1) {
+            enum_string << ", ";
           }
-          sql_string << ")";
-        } else {
-          sql_string << MysqlTypeString(mysql_type);
         }
-      } else {
+        enum_string << ")";
+      }
+
+      // bool to check if enum is oversized and we should use its plain type
+      bool over_sized_enum = enum_string.str().size() > (65536 / schema->attribute_num());
+
+      if (is_enum && !over_sized_enum && !empty_enum) {
+        // if the attribute has an enum and the enum values are not too many
+        sql_string << enum_string.str();
+      } else { // if not a usable enum continue as normal and use plain type
+        if (is_enum && over_sized_enum) {
+          std::string logMessage =
+              "Attribute " + attribute.name() +
+              " has too many enum values. Mytile is using its base type";
+          log_info(thd, logMessage.c_str());
+        }
         if (mysql_type == MYSQL_TYPE_VARCHAR) {
           sql_string << "TEXT";
         } else {
           sql_string << MysqlTypeString(mysql_type);
         }
       }
+
       if (!MysqlBlobType(enum_field_types(mysql_type)) &&
           TileDBTypeIsUnsigned(attribute.type()))
         sql_string << " UNSIGNED";