• ActiveRecord::Coder::JSON can be instantiated

  Options can now be passed to ActiveRecord::Coder::JSON when instantiating the coder. This allows:

  serialize :config, coder: ActiveRecord::Coder::JSON.new(symbolize_names: true)

  matthaigh27

• Deprecate using insert_all/upsert_all with unpersisted records in associations.

  Using these methods on associations containing unpersisted records will now show a deprecation warning, as the unpersisted records will be lost after the operation.

  Nick Schwaderer

• Make column name optional for index_exists?.

  This aligns well with remove_index signature as well, where index name doesn't need to be derived from the column names.

  Ali Ismayiliov

• Change the payload name of sql.active_record notification for eager loading from "SQL" to "#model.name Eager Load".

  zzak

• Enable automatically retrying idempotent #exists? queries on connection errors.

  Hartley McGuire, classidied

• Deprecate usage of unsupported methods in conjunction with update_all:

  update_all will now print a deprecation message if a query includes either WITH, WITH RECURSIVE or DISTINCT statements. Those were never supported and were ignored when generating the SQL query.

  An error will be raised in a future Rails release. This behaviour will be consistent with delete_all which currently raises an error for unsupported statements.

  Edouard Chin

• The table columns inside schema.rb are now sorted alphabetically.

  Previously they'd be sorted by creation order, which can cause merge conflicts when two branches modify the same table concurrently.

  John Duff

• Introduce versions formatter for the schema dumper.

  It is now possible to override how schema dumper formats versions information inside the structure.sql file. Currently, the versions are simply sorted in the decreasing order. Within large teams, this can potentially cause many merge conflicts near the top of the list.

  Now, the custom formatter can be provided with a custom sorting logic (e.g. by hash values of the versions), which can greatly reduce the number of conflicts.

  fatkodima

• Serialized attributes can now be marked as comparable.

  A not rare issue when working with serialized attributes is that the serialized representation of an object can change over time. Either because you are migrating from one serializer to the other (e.g. YAML to JSON or to msgpack), or because the serializer used subtly changed its output.

  One example is libyaml that used to have some extra trailing whitespaces, and recently fixed that. When this sorts of thing happen, you end up with lots of records that report being changed even though they aren't, which in the best case leads to a lot more writes to the database and in the worst case lead to nasty bugs.

  The solution is to instead compare the deserialized representation of the object, however Active Record can't assume the deserialized object has a working == method. Hence why this new functionality is opt-in.

  serialize :config, type: Hash, coder: JSON, comparable: true

  Jean Boussier

• Fix MySQL default functions getting dropped when changing a column's nullability.

  Bastian Bartmann

• SQLite extensions can be configured in config/database.yml.

  The database configuration option extensions: allows an application to load SQLite extensions when using sqlite3 >= v2.4.0. The array members may be filesystem paths or the names of modules that respond to .to_path:

  development:
    adapter: sqlite3
    extensions:
      - SQLean::UUID                     # module name responding to `.to_path`
      - .sqlpkg/nalgeon/crypto/crypto.so # or a filesystem path
      - <%= AppExtensions.location %>    # or ruby code returning a path
  

  Mike Dalessio

• ::ActiveRecord::Middleware::ShardSelector supports granular database connection switching.

  A new configuration option, class_name:, is introduced to config.active_record.shard_selector to allow an application to specify the abstract connection class to be switched by the shard selection middleware. The default class is ::ActiveRecord::Base.

  For example, this configuration tells ShardSelector to switch shards using AnimalsRecord.connected_to:

  config.active_record.shard_selector = { class_name: "AnimalsRecord" }

  Mike Dalessio

• Reset relations after insert_all/upsert_all.

  Bulk insert/upsert methods will now call reset if used on a relation, matching the behavior of update_all.

  Milo Winningham

• Use _N as a parallel tests databases suffixes

  Peviously, -N was used as a suffix. This can cause problems for RDBMSes which do not support dashes in database names.

  fatkodima

• Remember when a database connection has recently been verified (for two seconds, by default), to avoid repeated reverifications during a single request.

  This should recreate a similar rate of verification as in Rails 7.1, where connections are leased for the duration of a request, and thus only verified once.

  Matthew Draper

• Allow to reset cache counters for multiple records.

  Aircraft.reset_counters([1, 2, 3], :wheels_count)

  It produces much fewer queries compared to the custom implementation using looping over ids. Previously: O(ids.size * counters.size) queries, now: O(ids.size + counters.size) queries.

  fatkodima

• Add affected_rows to sql.active_record Notification.

  Hartley McGuire

• Fix sum when performing a grouped calculation.

  User.group(:friendly).sum no longer worked. This is fixed.

  Edouard Chin

• Add support for enabling or disabling transactional tests per database.

  A test class can now override the default use_transactional_tests setting for individual databases, which can be useful if some databases need their current state to be accessible to an external process while tests are running.

  class MostlyTransactionalTest < ActiveSupport::TestCase
    self.use_transactional_tests = true
    skip_transactional_tests_for_database :shared
  end

  Matthew Cheetham, Morgan Mareve

• Cast query_cache value when using URL configuration.

  zzak

• NULLS NOT DISTINCT works with UNIQUE CONSTRAINT as well as UNIQUE INDEX.

  Ryuta Kamizono

• PG::UnableToSend: no connection to the server is now retryable as a connection-related exception

  Kazuma Watanabe

Please check [8-0-stable]) for previous changes.