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| author | Ryuta Kamizono <kamipo@gmail.com> | 2019-03-13 09:29:00 +0900 |
|---|---|---|
| committer | Ryuta Kamizono <kamipo@gmail.com> | 2019-03-16 18:44:55 +0900 |
| commit | 97347d8c409f14b682dd9ec52ded3c869d0ba479 (patch) | |
| tree | 7baf7114da2ed0e305663085778267b6a3f06cb7 /activerecord/lib/active_record/connection_adapters/abstract_adapter.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/lib/active_record/connection_adapters/abstract_adapter.rb')
| -rw-r--r-- | activerecord/lib/active_record/connection_adapters/abstract_adapter.rb | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb index 202187a047..7aad306d50 100644 --- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb @@ -384,6 +384,11 @@ module ActiveRecord false end + # Does this adapter support optimizer hints? + def supports_optimizer_hints? + false + end + def supports_lazy_transactions? false end |