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author | Ryuta Kamizono <kamipo@gmail.com> | 2019-03-13 09:29:00 +0900 |
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committer | Ryuta Kamizono <kamipo@gmail.com> | 2019-03-16 18:44:55 +0900 |
commit | 97347d8c409f14b682dd9ec52ded3c869d0ba479 (patch) | |
tree | 7baf7114da2ed0e305663085778267b6a3f06cb7 /activerecord/test/cases/adapters/postgresql/optimizer_hints_test.rb | |
parent | 85984e50311b7138504abe1be9bbe99f96dde8ef (diff) | |
download | rails-97347d8c409f14b682dd9ec52ded3c869d0ba479.tar.gz rails-97347d8c409f14b682dd9ec52ded3c869d0ba479.tar.bz2 rails-97347d8c409f14b682dd9ec52ded3c869d0ba479.zip |
Support Optimizer Hints
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.
Diffstat (limited to 'activerecord/test/cases/adapters/postgresql/optimizer_hints_test.rb')
-rw-r--r-- | activerecord/test/cases/adapters/postgresql/optimizer_hints_test.rb | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/activerecord/test/cases/adapters/postgresql/optimizer_hints_test.rb b/activerecord/test/cases/adapters/postgresql/optimizer_hints_test.rb new file mode 100644 index 0000000000..1bfa815cac --- /dev/null +++ b/activerecord/test/cases/adapters/postgresql/optimizer_hints_test.rb @@ -0,0 +1,28 @@ +# frozen_string_literal: true + +require "cases/helper" +require "models/post" + +if supports_optimizer_hints? + class PostgresqlOptimzerHintsTest < ActiveRecord::PostgreSQLTestCase + fixtures :posts + + def setup + enable_extension!("pg_hint_plan", ActiveRecord::Base.connection) + end + + def test_optimizer_hints + assert_sql(%r{\ASELECT /\*\+ SeqScan\(posts\) \*/}) do + posts = Post.optimizer_hints("SeqScan(posts)") + posts = posts.select(:id).where(author_id: [0, 1]) + assert_includes posts.explain, "Seq Scan on posts" + end + + assert_sql(%r{\ASELECT /\*\+ SeqScan\(posts\) \*/}) do + posts = Post.optimizer_hints("/*+ SeqScan(posts) */") + posts = posts.select(:id).where(author_id: [0, 1]) + assert_includes posts.explain, "Seq Scan on posts" + end + end + end +end |