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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/arel/visitors/depth_first.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/arel/visitors/depth_first.rb')
| -rw-r--r-- | activerecord/lib/arel/visitors/depth_first.rb | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/activerecord/lib/arel/visitors/depth_first.rb b/activerecord/lib/arel/visitors/depth_first.rb index 92d309453c..892d670c79 100644 --- a/activerecord/lib/arel/visitors/depth_first.rb +++ b/activerecord/lib/arel/visitors/depth_first.rb @@ -35,6 +35,7 @@ module Arel # :nodoc: all alias :visit_Arel_Nodes_Ascending :unary alias :visit_Arel_Nodes_Descending :unary alias :visit_Arel_Nodes_UnqualifiedColumn :unary + alias :visit_Arel_Nodes_OptimizerHints :unary def function(o) visit o.expressions |