Do not query database for non-spatial tables

activerecord-postgis-adapter.gemspec

@@ -20,4 +20,5 @@ require './lib/active_record/connection_adapters/postgis_adapter/version.rb'
   spec.add_dependency 'rgeo-activerecord', '~> 1.0.0'
 
   spec.add_development_dependency 'rake', '~> 10.2'
+  spec.add_development_dependency 'mocha', '~> 1.0'
 end

lib/active_record/connection_adapters/postgis_adapter.rb

@@ -16,15 +16,16 @@ module PostGISAdapter
 require 'active_record/connection_adapters/postgresql_adapter'
 require 'rgeo/active_record'
 
-require 'active_record/connection_adapters/postgis_adapter/version.rb'
-require 'active_record/connection_adapters/postgis_adapter/common_adapter_methods.rb'
-require 'active_record/connection_adapters/postgis_adapter/main_adapter.rb'
-require 'active_record/connection_adapters/postgis_adapter/spatial_table_definition.rb'
-require 'active_record/connection_adapters/postgis_adapter/spatial_column.rb'
-require 'active_record/connection_adapters/postgis_adapter/arel_tosql.rb'
-require 'active_record/connection_adapters/postgis_adapter/setup.rb'
+require 'active_record/connection_adapters/postgis_adapter/version'
+require 'active_record/connection_adapters/postgis_adapter/common_adapter_methods'
+require 'active_record/connection_adapters/postgis_adapter/main_adapter'
+require 'active_record/connection_adapters/postgis_adapter/spatial_column_info'
+require 'active_record/connection_adapters/postgis_adapter/spatial_table_definition'
+require 'active_record/connection_adapters/postgis_adapter/spatial_column'
+require 'active_record/connection_adapters/postgis_adapter/arel_tosql'
+require 'active_record/connection_adapters/postgis_adapter/setup'
 require 'active_record/connection_adapters/postgis_adapter/create_connection'
-require 'active_record/connection_adapters/postgis_adapter/postgis_database_tasks.rb'
+require 'active_record/connection_adapters/postgis_adapter/postgis_database_tasks'
 
 ::ActiveRecord::ConnectionAdapters::PostGISAdapter.initial_setup
 

lib/active_record/connection_adapters/postgis_adapter/main_adapter.rb

@@ -31,8 +31,8 @@ def type_cast(value, column, array_member = false)
         # FULL REPLACEMENT. RE-CHECK ON NEW VERSIONS
         # https://github.com/rails/rails/blob/master/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
         def columns(table_name, name = nil)
+          column_info = SpatialColumnInfo.new(self, quote_string(table_name.to_s))
           # Limit, precision, and scale are all handled by the superclass.
-          spatial_info_ = spatial_column_info(table_name)
           column_definitions(table_name).map do |column_name, type, default, notnull, oid, fmod|
             oid = column_type_map.fetch(oid.to_i, fmod.to_i) { OID::Identity.new }
             SpatialColumn.new(@rgeo_factory_settings,
@@ -42,7 +42,7 @@ def columns(table_name, name = nil)
                               oid,
                               type,
                               notnull == 'f',
-                              type =~ /geometry/i ? spatial_info_[column_name] : nil)
+                              column_info.get(column_name, type))
           end
         end
 
@@ -158,25 +158,7 @@ def add_index(table_name, column_name, options = {})
         end
 
         def spatial_column_info(table_name)
-          info = query("SELECT f_geometry_column,coord_dimension,srid,type FROM geometry_columns WHERE f_table_name='#{quote_string(table_name.to_s)}'")
-          result = {}
-          info.each do |row|
-            name = row[0]
-            type = row[3]
-            dimension = row[1].to_i
-            has_m = !!(type =~ /m$/i)
-            type.sub!(/m$/, '')
-            has_z = dimension > 3 || dimension == 3 && !has_m
-            result[name] = {
-              dimension: dimension,
-              has_m:     has_m,
-              has_z:     has_z,
-              name:      name,
-              srid:      row[2].to_i,
-              type:      type,
-            }
-          end
-          result
+          SpatialColumnInfo.new(self, quote_string(table_name.to_s)).all
         end
 
         private
@@ -215,7 +197,6 @@ def set_dimensions(has_m, has_z)
           dimensions += 1 if has_m
           dimensions
         end
-
       end
     end
   end

lib/active_record/connection_adapters/postgis_adapter/spatial_column_info.rb

@@ -0,0 +1,44 @@
+module ActiveRecord  # :nodoc:
+  module ConnectionAdapters  # :nodoc:
+    module PostGISAdapter
+      # Do spatial sql queries for column info and memoize that info.
+      class SpatialColumnInfo
+        attr_accessor :adapter, :table_name
+
+        def initialize(adapter, table_name)
+          @adapter = adapter
+          @table_name = table_name
+        end
+
+        def all
+          info = adapter.query("SELECT f_geometry_column,coord_dimension,srid,type FROM geometry_columns WHERE f_table_name='#{table_name}'")
+          result = {}
+          info.each do |row|
+            name = row[0]
+            type = row[3]
+            dimension = row[1].to_i
+            has_m = !!(type =~ /m$/i)
+            type.sub!(/m$/, '')
+            has_z = dimension > 3 || dimension == 3 && !has_m
+            result[name] = {
+              dimension: dimension,
+              has_m:     has_m,
+              has_z:     has_z,
+              name:      name,
+              srid:      row[2].to_i,
+              type:      type,
+            }
+          end
+          result
+        end
+
+        # will not query the database for non-spatial columns/tables
+        def get(column_name, type)
+          return nil unless type =~ /geometry/i
+          @spatial_column_info ||= all
+          @spatial_column_info[column_name]
+        end
+      end
+    end
+  end
+end

test/ddl_test.rb

@@ -225,8 +225,32 @@ def test_create_geometry_using_limit
               assert_equal(0, klass.connection.select_value(geometry_column_count_query).to_i)
             end
 
+            def test_caches_spatial_column_info
+              klass = create_ar_class
+              klass.connection.create_table(:spatial_test, force: true) do |t|
+                t.point 'latlon'
+                t.point 'other'
+              end
+              ::ActiveRecord::ConnectionAdapters::PostGISAdapter::SpatialColumnInfo.any_instance.expects(:all).once.returns({})
+              klass.columns
+              klass.columns
+            end
+
+            def test_no_query_spatial_column_info
+              klass = create_ar_class
+              klass.connection.create_table(:spatial_test, force: true) do |t|
+                t.string 'name'
+              end
+              # `all` queries column info from the database - it should not be called when klass.columns is called
+              ::ActiveRecord::ConnectionAdapters::PostGISAdapter::SpatialColumnInfo.any_instance.expects(:all).never
+              # first column is id, second is name
+              refute klass.columns[1].spatial?
+              assert_nil klass.columns[1].has_z
+            end
           end
 
+          private
+
           def geometry_column_count_query
             "SELECT COUNT(*) FROM geometry_columns WHERE f_table_name='spatial_test'"
           end