activerecord-explain-analyze CircleCI

Extends ActiveRecord#explain with support for EXPLAIN ANALYZE and output formats of JSON, XML, and YAML.

It currently supports ActiveRecord 4 and 5, and PostgreSQL only.

Examples:

Wallet.where(base_currency: "USD").explain(analyze: true)

Results in:

EXPLAIN for: SELECT "wallets".* FROM "wallets" WHERE "wallets"."deleted_at" IS NULL AND "wallets"."base_currency" = $1
Bitmap Heap Scan on public.wallets  (cost=4.16..9.50 rows=1 width=164) (actual time=0.008..0.012 rows=30 loops=1)
  Output: id, canonical_id, client_id, wallet_type, base_currency, created_at, updated_at, deleted_at
  Recheck Cond: (wallets.deleted_at IS NULL)
  Filter: ((wallets.base_currency)::text = 'USD'::text)
  Heap Blocks: exact=1
  Buffers: shared hit=2
  ->  Bitmap Index Scan on index_wallets_on_deleted_at  (cost=0.00..4.16 rows=2 width=0) (actual time=0.003..0.003 rows=32 loops=1)
        Index Cond: (wallets.deleted_at IS NULL)
        Buffers: shared hit=1
Planning time: 0.041 ms
Execution time: 0.026 ms
Wallet.where(base_currency: "USD").explain(analyze: true, format: :json)

Results in:

[
  {
    "Plan": {
      "Node Type": "Bitmap Heap Scan",
      "Parallel Aware": false,
      "Relation Name": "wallets",
      "Schema": "public",
      "Alias": "wallets",
      "Startup Cost": 4.16,
      "Total Cost": 9.50,
      "Plan Rows": 1,
      "Plan Width": 164,
      "Actual Startup Time": 0.008,
      "Actual Total Time": 0.013,
      "Actual Rows": 30,
      ...

You can then paste this JSON output into PEV or similar tools to get a visualization of the EXPLAIN query output:

screen shot 2017-10-27 at 4 24 38 pm

Installation

Add this line to your application's Gemfile and run bundle to install:

gem 'activerecord-explain-analyze'

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.