Results | Source

Measure the performance of Ruby tree/hierarchy gems. Find what's slow, prove what's fast, and give maintainers evidence for making changes.

Primarily benchmarks ancestry with closure_tree for cross-library comparison.

• Built a benchmark suite covering read operations, write operations, format comparisons, and version-over-version tracking.
• Tested ancestry configurations (mp1, mp2, mp3, ltree, array) with options like cache_depth, parent, and virtual columns.
• Compared against closure_tree to expose blind spots that only show up when you look at a different architecture.
• Trees are tested with 600-6,000 at 2-50 nodes deep.
• Note: most real-world hierarchies are broad and shallow
  • biological taxonomies go ~9 levels deep
  • large org charts rarely exceed 12.

Both gems are Ruby libraries generating SQL. A technique one uses can often be adopted by the other. Comparing across gems is how you tell "this approach is fundamentally slower" from "this implementation has a fixable inefficiency."

• Comparing with closure_tree exposed that ancestry had a 387x gap on parent.
• closure_tree does arrange better and pulls ahead at very large scales.
• closure_tree caches parent_id from the hierarchy. This can be done with ancestry as well.
• I had expected closure_tree to perform better with deep hierarchies, but the extra nodes slowed it down.

Wrote up a more details description of our findings.md

See the results page for benchmarks, charts, and a glossary of configurations.

• Ordered descendants -- where closure_tree's hierarchy table ordering should shine
• Write cost comparison -- ancestry updates one column, closure_tree maintains a hierarchy table
• Add more alternatives
  • awesome_nested_set -- nested set pattern (lft/rgt columns)
  • acts_as_recursive_tree -- parent_id with WITH RECURSIVE
  • acts_as_sane_tree -- parent_id with WITH RECURSIVE

Requires local checkouts of ancestry and benchmark-sweet as sibling directories.

bundle install

# compare ancestry configurations
DB=pg bundle exec ruby read_bench.rb --all
DB=pg bundle exec ruby write_bench.rb --all

# compare ancestry versions (requires ancestry git worktrees)
DB=pg bundle exec ruby read_bench.rb -v v5.0.0
DB=pg bundle exec ruby read_bench.rb -v master

# compare libraries
DB=pg bundle exec ruby compare_bench.rb

# generate HTML charts and tables
bundle exec ruby gen_html.rb