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* Revert unused code and re-using query annotation for `update_all` and ↵Ryuta Kamizono2019-04-011-4/+0
| | | | | | | | | | | | | | | | `delete_all` This partly reverts #35617. #35617 includes unused code (for `InsertStatement`) and re-using query annotation for `update_all` and `delete_all`, which has not been discussed yet. If a relation has any annotation, I think it is mostly for SELECT query, so re-using annotation by default is not always desired behavior for me. We should discuss about desired behavior before publishing the implementation.
* Add Relation#annotate for SQL commentingMatt Yoho2019-03-211-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch has two main portions: 1. Add SQL comment support to Arel via Arel::Nodes::Comment. 2. Implement a Relation#annotate method on top of that. == Adding SQL comment support Adds a new Arel::Nodes::Comment node that represents an optional SQL comment and teachers the relevant visitors how to handle it. Comment nodes may be added to the basic CRUD statement nodes and set through any of the four (Select|Insert|Update|Delete)Manager objects. For example: manager = Arel::UpdateManager.new manager.table table manager.comment("annotation") manager.to_sql # UPDATE "users" /* annotation */ This new node type will be used by ActiveRecord::Relation to enable query annotation via SQL comments. == Implementing the Relation#annotate method Implements `ActiveRecord::Relation#annotate`, which accepts a comment string that will be appeneded to any queries generated by the relation. Some examples: relation = Post.where(id: 123).annotate("metadata string") relation.first # SELECT "posts".* FROM "posts" WHERE "posts"."id" = 123 # LIMIT 1 /* metadata string */ class Tag < ActiveRecord::Base scope :foo_annotated, -> { annotate("foo") } end Tag.foo_annotated.annotate("bar").first # SELECT "tags".* FROM "tags" LIMIT 1 /* foo */ /* bar */ Also wires up the plumbing so this works with `#update_all` and `#delete_all` as well. This feature is useful for instrumentation and general analysis of queries generated at runtime.
* Support Optimizer HintsRyuta Kamizono2019-03-161-0/+7
| | | | | | | | | | | | | | | | | | We as Arm Treasure Data are using Optimizer Hints with a monkey patch (https://gist.github.com/kamipo/4c8539f0ce4acf85075cf5a6b0d9712e), especially in order to use `MAX_EXECUTION_TIME` (refer #31129). Example: ```ruby class Job < ApplicationRecord default_scope { optimizer_hints("MAX_EXECUTION_TIME(50000) NO_INDEX_MERGE(jobs)") } end ``` Optimizer Hints is supported not only for MySQL but also for most databases (PostgreSQL on RDS, Oracle, SQL Server, etc), it is really helpful to turn heavy queries for large scale applications.
* Remove unused `Row` class in `SelectManager`Ryuta Kamizono2019-03-131-12/+0
| | | | The `Row` class is no longer used since d956772b3c61d97940ebcccd7c83e2397ca0c36c.
* Abandon TOP support.Vladimir Kochnev2018-09-251-2/+0
| | | | | | | | | | | | | | | | Initially, `TOP` was introduced to support `limit` for MSSQL database. Unlike PostgreSQL/MySQL/SQLite, MSSQL does not have native `LIMIT`/`OFFSET` support. The commit adding `TOP` is 1a246f71616cf246a75ef6cbdb56032e43d4e643. However, it figured out that `TOP` implementation was weak and it's not sufficient to also support `OFFSET`, then `TOP` was substituted with `ROW_NUMBER()` subquery in be48ed3071fd6524d0145c4ad3faeb4aafe3eda3. This is a well known trick in MSSQL - https://stackoverflow.com/questions/2135418/equivalent-of-limit-and-offset-for-sql-server. So now we don't need this `visit_Arel_Nodes_Top` at all. It does nothing useful but also adds an extra space after `SELECT` when `LIMIT` is being used for **any** database.
* Remove unused `existing` arg in `SelectManager#collapse`Ryuta Kamizono2018-09-111-3/+3
| | | | | The `existing` arg was added at 8bc0fce, but it is no longer used since aac9da2.
* Arel: :nodoc: allMatthew Draper2018-02-241-1/+1
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* Arel: rubocop -aMatthew Draper2018-02-241-40/+41
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* Merge Arel into Active RecordMatthew Draper2018-02-241-0/+272