Cache database version in schema cache

  * The database version will get cached in the schema cache file during the
    schema cache dump. When the database version check happens, the version will
    be pulled from the schema cache and thus avoid querying the database for
    the version.
  * If the schema cache file doesn't exist, we'll query the database for the
    version and cache it on the schema cache object.
  * To facilitate this change, all connection adapters now implement
    #get_database_version and #database_version. #database_version returns the
    value from the schema cache.
  * To take advantage of the cached database version, the database version check
    will now happen after the schema cache is set on the connection in the
    connection pool.

1 files changed, 1 insertions, 1 deletions

diff --git a/activerecord/test/cases/migration/columns_test.rb b/activerecord/test/cases/migration/columns_test.rb
index dbbba9c5fa..cce3461e18 100644
--- a/activerecord/test/cases/migration/columns_test.rb
+++ b/activerecord/test/cases/migration/columns_test.rb
@@ -136,7 +136,7 @@ module ActiveRecord
       def test_remove_column_with_multi_column_index
         # MariaDB starting with 10.2.8
         # Dropping a column that is part of a multi-column UNIQUE constraint is not permitted.
-        skip if current_adapter?(:Mysql2Adapter) && connection.mariadb? && connection.version >= "10.2.8"
+        skip if current_adapter?(:Mysql2Adapter) && connection.mariadb? && connection.database_version >= "10.2.8"
 
         add_column "test_models", :hat_size, :integer
         add_column "test_models", :hat_style, :string, limit: 100