ActiveRecord Analyze

This gem adds an analyze method to Active Record query objects. It executes EXPLAIN ANALYZE on a query SQL.

Installation

In your Gemfile:

```ruby

gem ‘activerecord-analyze’

```

Options

The analyze method supports the following EXPLAIN query options (PG docs reference)[https://www.postgresql.org/docs/12/sql-explain.html]:

VERBOSE [ boolean ] COSTS [ boolean ] SETTINGS [ boolean ] BUFFERS [ boolean ] TIMING [ boolean ] SUMMARY [ boolean ] FORMAT { TEXT | XML | JSON | YAML }

You can pass the options like that:

```ruby

User.all.analyze( format: :json, verbose: true, costs: true, settings: true, buffers: true, timing: true, summary: true )

EXPLAIN (FORMAT JSON, ANALYZE, VERBOSE, COSTS, SETTINGS, BUFFERS, TIMING, SUMMARY)

# SELECT “users”.* FROM “users” # [ # { # “Plan”: { # “Node Type”: “Seq Scan”, # “Parallel Aware”: false, # “Relation Name”: “users”, # “Schema”: “public”, # “Alias”: “users”, # “Startup Cost”: 0.00, # “Total Cost”: 11.56, # “Plan Rows”: 520, # “Plan Width”: 127, # “Actual Startup Time”: 0.006, # “Actual Total Time”: 0.007, # “Actual Rows”: 2, # “Actual Loops”: 1, # “Shared Hit Blocks”: 1, # “Shared Read Blocks”: 0, # “Shared Dirtied Blocks”: 0, # “Shared Written Blocks”: 0, # “Local Hit Blocks”: 0, # “Local Read Blocks”: 0, # “Local Dirtied Blocks”: 0, # “Local Written Blocks”: 0, # “Temp Read Blocks”: 0, # “Temp Written Blocks”: 0, # “I/O Read Time”: 0.000, # “I/O Write Time”: 0.000 # }, # “Settings”: { # “cpu_index_tuple_cost”: “0.001”, # “cpu_operator_cost”: “0.0005”, # “cpu_tuple_cost”: “0.003”, # “effective_cache_size”: “10800000kB”, # “max_parallel_workers_per_gather”: “1”, # “random_page_cost”: “2”, # “work_mem”: “100MB” # }, # “Planning Time”: 0.033, # “Triggers”: [ # ], # “Execution Time”: 0.018 # } # ]

```

Optionally you can disable running the ANALYZE query and only generate the plan:

```ruby

User.all.analyze(analyze: false)

EXPLAIN ANALYZE for: SELECT “users”.* FROM “users”

# QUERY PLAN # ———————————————————- # Seq Scan on users (cost=0.00..15.20 rows=520 width=127)

```

Disclaimer

It is a bit experimental and can break with new Rails release.