Performance improvements experiment

[cgewecke]

This PR was an attempt to address an unexpected performance slowdown relative to 0.6.x (which sync writes each instrumentation event to file at the vm and should be much slower than an in-memory approach).

Tried:

• using memdown as provider db (per suggestion at ganache-core 481 (in-memory db writes)
• using ganache.server instead of ganache.provider (maybe web3 treats those differently?)
• simplifying step handler logic slightly (since it might run millions of times)
• ganache 6.4.1 through 6.7.0
• --max-old-space-size=4096 in combination with memdown

There's some (inconclusive) variance run-to-run but overall it seems that in-process is just slower than stand-alone.

Benchmarking was vs. zeppelin in these workflows. Results ranged from 30 - 100% slowdown relative to a non-coverage test run using a separately launched client.

Each run compared three jobs (~2200 unit tests) (from fast to slow):

• test (stand-alone - typically 8.5 min )
• test_inprocess (e.g no coverage, using provider ~10 min)
• coverage (coverage, using provider, ~12 min)

Closing for now....

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (truffle-plugin@c8870a0). Click here to learn what that means.
The diff coverage is 92.85%.

@@                Coverage Diff                @@
##             truffle-plugin     #397   +/-   ##
=================================================
  Coverage                  ?   92.36%           
=================================================
  Files                     ?       10           
  Lines                     ?      550           
  Branches                  ?        0           
=================================================
  Hits                      ?      508           
  Misses                    ?       42           
  Partials                  ?        0

Impacted Files	Coverage Δ
lib/collector.js	100% <100%> (ø)
lib/app.js	90.84% <90%> (ø)
dist/truffle.plugin.js	85% <90%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c8870a0...715f019. Read the comment docs.

[cgewecke]

See PR description above...