schema_builder: calculate is_dense from the schema builder

We currently have code to calculate "is_dense" in the create statement handler.
That obviously don't work for the system schemas, which are not defined this
way.

Since all of our schemas now have to pass through the schema_builder one way or
another, that is the best place in which to do that calculation.

Note that unfortunately, that does not mean we can just get rid of
set_is_dense() in the schema builder: we still need to set it in some
situations, where for instance, we read that property in schema_columnfamilies,
and then apply to the relevant CF. Those uses are, however, all internal to
legacy_schema_tables.cc

Signed-off-by: Glauber Costa <glommer@cloudius-systems.com>

cql3/statements/create_table_statement.cc

@@ -106,7 +106,7 @@ shared_ptr<transport::event::schema_change> create_table_statement::change_event
 schema_ptr create_table_statement::get_cf_meta_data() {
     schema_builder builder{keyspace(), column_family()};
     apply_properties_to(builder);
-    return builder.build();
+    return builder.build(_use_compact_storage ? schema_builder::compact_storage::yes : schema_builder::compact_storage::no);
 }
 
 void create_table_statement::apply_properties_to(schema_builder& builder) {
@@ -118,8 +118,6 @@ void create_table_statement::apply_properties_to(schema_builder& builder) {
     cfmd.defaultValidator(defaultValidator)
         .addAllColumnDefinitions(getColumns(cfmd))
 #endif
-    builder.set_is_dense(_is_dense);
-
     add_column_metadata_from_aliases(builder, _key_aliases, _partition_key_types, column_kind::partition_key);
     add_column_metadata_from_aliases(builder, _column_aliases, _clustering_key_types, column_kind::clustering_key);
 #if 0
@@ -187,6 +185,8 @@ ::shared_ptr<parsed_statement::prepared> create_table_statement::raw_statement::
         throw exceptions::invalid_request_exception("Multiple PRIMARY KEYs specifed (exactly one required)");
     }
 
+    stmt->_use_compact_storage = _use_compact_storage;
+
     auto& key_aliases = _key_aliases[0];
     std::vector<data_type> key_types;
     for (auto&& alias : key_aliases) {
@@ -202,10 +202,6 @@ ::shared_ptr<parsed_statement::prepared> create_table_statement::raw_statement::
     }
     stmt->_partition_key_types = key_types;
 
-    // Dense means that no part of the comparator stores a CQL column name. This means
-    // COMPACT STORAGE with at least one columnAliases (otherwise it's a thrift "static" CF).
-    stmt->_is_dense = _use_compact_storage && !_column_aliases.empty();
-
     // Handle column aliases
     if (_column_aliases.empty()) {
         if (_use_compact_storage) {

cql3/statements/create_table_statement.hh

@@ -55,7 +55,7 @@ class create_table_statement : public schema_altering_statement {
 #if 0
     private ByteBuffer valueAlias;
 #endif
-    bool _is_dense;
+    bool _use_compact_storage;
 
     using column_map_type =
         std::unordered_map<::shared_ptr<column_identifier>,

schema.cc

@@ -342,6 +342,11 @@ schema_builder& schema_builder::with_column(bytes name, data_type type, index_in
     return *this;
 }
 
-schema_ptr schema_builder::build() {
-    return make_lw_shared<schema>(schema(_raw));
+schema_ptr schema_builder::build(compact_storage cp) {
+    schema s(_raw);
+
+    // Dense means that no part of the comparator stores a CQL column name. This means
+    // COMPACT STORAGE with at least one columnAliases (otherwise it's a thrift "static" CF).
+    s._raw._is_dense = (cp == compact_storage::yes) && (s.clustering_key_size() > 0);
+    return make_lw_shared<schema>(std::move(s));
 }

schema_builder.hh

@@ -128,5 +128,6 @@ public:
 
     void add_default_index_names(database&);
 
-    schema_ptr build();
+    enum class compact_storage { no, yes };
+    schema_ptr build(compact_storage = compact_storage::no);
 };