AwesomeExplain

AwesomeExplain provides the same APM's level of query analysis under your development and test Rails environments.

Main Features

  • A set of utilities for analyzing MongoDB and SQL queries from Rails console.
  • Tracking queries under your database of choice (SQLite3 or PostgreSQL) which can be viewed under Athena's dashboard.

Build Status Build Status License: MIT

Installation

Add the following line to your application's Gemfile:

gem 'awesome_explain', require: true

Console Utility Methods

  • ae: Prints a query's execution plan using a user friendly terminal table
    • Currently supports the following classes:
    • Mongo::Collection::View::Aggregation
    • Mongoid::Criteria
    • ActiveRecord::Relation
  • analyze: Prints a summary of all MongoDB queries passed to the Ruby block
  • analyze_ar: Prints a summary of all ActiveRecord queries passed to the Ruby block

Detailed usage examples can be found below.

MongoDB

Usage

ae Article.where(author_id: '5b9ec484d5cc2e697189d7c9')

+--------------------+-----------------------------+
| Winning Plan       | FETCH (7 / 7) -> IXSCAN (7) |
+--------------------+-----------------------------+
| Used Indexes       | author_id_1 (forward)       |
+--------------------+-----------------------------+
| Rejected Plans     | 0                           |
+--------------------+-----------------------------+
| Documents Returned | 7                           |
+--------------------+-----------------------------+
| Documents Examined | 7                           |
+--------------------+-----------------------------+
| Keys Examined      | 7                           |
+--------------------+-----------------------------+
| Execution time(ms) | 0                           |
+--------------------+-----------------------------+
| Execution time(s)  | 0.0                         |
+--------------------+-----------------------------+

ae Article.or([{author_id: '5b9ec484d5cc2e697189d7c9', state: 'published'}, {created_at: 3.days.ago}])


+--------------------+-------------------------------------------------------------------------------------------------------------------------------------------+
| Winning Plan       | SORT (20) -> SORT_KEY_GENERATOR (20) -> FETCH (24 / 20) -> OR (24) -> [  FETCH (24 / 24) -> IXSCAN (24) ,  FETCH (0 / 0) -> IXSCAN (0) ]  |
+--------------------+-------------------------------------------------------------------------------------------------------------------------------------------+
| Used Indexes       | state_1 (forward), author_id_1 (forward)                                                                                                  |
+--------------------+-------------------------------------------------------------------------------------------------------------------------------------------+
| Rejected Plans     | 18                                                                                                                                        |
+--------------------+-------------------------------------------------------------------------------------------------------------------------------------------+
| Documents Returned | 20                                                                                                                                        |
+--------------------+-------------------------------------------------------------------------------------------------------------------------------------------+
| Documents Examined | 48                                                                                                                                        |
+--------------------+-------------------------------------------------------------------------------------------------------------------------------------------+
| Keys Examined      | 24                                                                                                                                        |
+--------------------+-------------------------------------------------------------------------------------------------------------------------------------------+
| Execution time(ms) | 37                                                                                                                                        |
+--------------------+-------------------------------------------------------------------------------------------------------------------------------------------+
| Execution time(s)  | 0.037                                                                                                                                     |
+--------------------+-------------------------------------------------------------------------------------------------------------------------------------------+

ae Product.where(_id: 22)

+--------------------+----------------+
| Winning Plan       | IDHACK (1 / 1) |
+--------------------+----------------+
| Used Indexes       |                |
+--------------------+----------------+
| Rejected Plans     | 0              |
+--------------------+----------------+
| Documents Returned | 1              |
+--------------------+----------------+
| Documents Examined | 1              |
+--------------------+----------------+
| Keys Examined      | 1              |
+--------------------+----------------+
| Execution time(ms) | 90             |
+--------------------+----------------+
| Execution time(s)  | 0.09           |
+--------------------+----------------+

Winning Plan Examples

FETCH (7 / 7) -> IXSCAN (7)

Below is a breakdown of the above winning plan:

  • First stage is a FETCH stage. 7 documents were examined, and 7 were returned.
  • Second stage was an IXSCAN stage were 7 documents were returned.

For information about MongoDB's explain output, please refer to the official MongoDB Explain documentation: https://docs.mongodb.com/manual/reference/explain-results/

PostgreSQL

ae Usage

Query using PK index

ae Film.where(film_id: 1)

+--------------------+-------+
|       General Stats        |
+--------------------+-------+
| Table              | Count |
+--------------------+-------+
| Total Rows Planned | 1     |
| Total Rows         | 1     |
| Total Loops        | 1     |
| Seq Scans          | 0     |
| Indexes Used       | 1     |
+--------------------+-------+
|        Table Stats         |
+--------------------+-------+
| Table              | Count |
+--------------------+-------+
| film               | 1     |
+--------------------+-------+
|      Node Type Stats       |
+--------------------+-------+
| Node Type          | Count |
+--------------------+-------+
| Index Scan         | 1     |
+--------------------+-------+
|        Index Stats         |
+--------------------+-------+
| Index Name         | Count |
+--------------------+-------+
| film_pkey          | 1     |
+--------------------+-------+

Query not using any index

ae Film.where(description: 'Alien Center')

+--------------------+-------+
|       General Stats        |
+--------------------+-------+
| Table              | Count |
+--------------------+-------+
| Total Rows Planned | 1     |
| Total Rows         | 0     |
| Total Loops        | 1     |
| Seq Scans          | 1     |
| Indexes Used       | 0     |
+--------------------+-------+
|        Table Stats         |
+--------------------+-------+
| Table              | Count |
+--------------------+-------+
| film               | 1     |
+--------------------+-------+
|      Node Type Stats       |
+--------------------+-------+
| Node Type          | Count |
+--------------------+-------+
| Seq Scan           | 1     |
+--------------------+-------+

analyze_ar Usage

analyze_ar { Film.where(film_id: 1).to_a; Actor.where(last_name: 'Cage').to_a };0

+--------------------+----------------+
| Time (sec)         | 0.0            |
+--------------------+----------------+
| Total Rows Planned | 3              |
+--------------------+----------------+
| Total Rows         | 3              |
+--------------------+----------------+
| Total Loops        | 2              |
+--------------------+----------------+
| Seq Scans          | 1              |
+--------------------+----------------+
| Tables             | film (1)       |
|                    | actor (1)      |
+--------------------+----------------+
| Node Types         | Index Scan (1) |
|                    | Seq Scan (1)   |
+--------------------+----------------+
| Indexes            | film_pkey (1)  |
+--------------------+----------------+

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/sandboxws/awesome_explain. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the AwesomeExplain project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.