Prior to this commit, Rails makes no differentiation between whether a
query uses bind parameters, and whether or not we cache that query as a
prepared statement. This leads to the cache populating extremely fast in
some cases, with the statements never being reused.
In particular, the two problematic cases are `where(foo: [1, 2, 3])` and
`where("foo = ?", 1)`. In both cases we'll end up quoting the values
rather than using a bind param, causing a cache entry for every value
ever used in that query.
It was noted that we can probably eventually change `where("foo = ?",
1)` to use a bind param, which would resolve that case. Additionally, on
PG we can change our generated query to be `WHERE foo = ANY($1)`, and
pass an array for the bind param. I hope to accomplish both in the
future.
For SQLite and MySQL, we still end up preparing the statements anyway,
we just don't cache it. The statement will be cleaned up after it is
executed. On postgres, we skip the prepare step entirely, as an API is
provided to execute with bind params without preparing the statement.
I'm not 100% happy on the way this ended up being structured. I was
hoping to use a decorator on the visitor, rather than mixing a module
into the object, but the way Arel has it's visitor pattern set up makes
it very difficult to extend without inheritance. I'd like to remove the
duplication from the various places that are extending it, but that'll
require a larger restructuring of that initialization logic. I'm going
to take another look at the structure of it soon.
This changes the signature of one of the adapter's internals, and will
require downstream changes from third party adapters. I'm not too
worried about this, as worst case they can simply add the parameter and
always ignore it, and just keep their previous behavior.
Fixes#21992.
Sure this is `destroy` method of PhotosController, but in this chapter
these methods which mapped by the router are called "action".
For example:
```ruby
get '/patients/:id', to: 'patients#show'
```
is described to dispatch "controller's `show` action".
Prior to this change, given a route:
# config/routes.rb
get ':a' => "foo#bar"
If one pointed to http://example.com/%BE (param `a` has invalid encoding),
a `BadRequest` would be raised with the following non-informative message:
ActionController::BadRequest
From now on the message displayed is:
Invalid parameter encoding: hi => "\xBE"
Fixes#21923.
With `unscope!` called last, it undoes `where` constraints of the same
value when the `where` is chained after the `unscope`. This is what a
`rewhere` does. This is undesirable behavior.
The included tests demonstrate both the `unscope(...).where(...)`
behavior as well as the direct use of `rewhere(...)`.
This is in reference to #21955.
This commit follow up of 4d8f62d.
The difference from 4d8f62d are below:
* Change `WhereClauseFactory` to accept `Arel::Nodes::Node`
* Change test cases of `relation_test.rb`
In the Rails console, the `helper` function provides a shorthand for
working with application helpers. However, `helper` memoizes the
value of `ApplicationController#helpers`. This means that if a user
subsequently changes helper code and calls `reload!` in the console,
their code changes will not be reflected by the `helper` function,
even though the helper was, in fact, reloaded.
`WhereClauseFactory` handles all other branches based on argument types,
so the code fits more naturally here, and it's just where the
responsibility belongs.
The default timestamp used for AR is `updated_at` in nanoseconds! (:nsec) This causes issues on any machine that runs an OS that supports nanoseconds timestamps, i.e. not-OS X, where the cache_key of the record persisted in the database (milliseconds precision) is out-of-sync with the cache_key in the ruby VM.
This commit adds:
A test that shows the issue, it can be found in the separate file `cache_key_test.rb`, because
- model couldn't be defined inline
- transactional testing needed to be turned off to get it to pass the MySQL tests
This seemed cleaner than putting it in an existing testcase file.
It adds :usec as a dateformat that calculates datetime in microseconds
It sets precision of cache_key to :usec instead of :nsec, as no db supports nsec precision on timestamps
