[Bug]: 30-50% performance drop since v19.7.1

[feesler]

Bug expectation

Similar to #8650 but not so dramatic.

Steps to reproduce the problem:

1. Install puppeteer v19.7.0 dependency
2. import puppeteer from 'puppeteer';
3. Run some script and measure performance
4. Update puppeteer to v19.7.1 and repeat step 3

Updated https://github.com/feesler/puppeteer-perf package to test this issue.
Script will download Chromium revision 1095492 to discard possible difference in browser performance.
Try to run several times to avoid caching effects or give URL with more elements on page.

Bug behavior

• Flaky
• PDF

Minimal, reproducible example

git clone https://github.com/feesler/puppeteer-perf.git
cd puppeteer-perf
npm install
npm test
npm install puppeteer@19.7.1
npm test

Error string

no error

Puppeteer configuration

No response

Puppeteer version

19.8.5

Node version

19.8.1

Package manager

npm

Package manager version

8.13.2

Operating system

Windows

[github-actions]

This issue was not reproducible. Please check that your example runs locally and the following:

• Ensure the script does not rely on dependencies outside of puppeteer and puppeteer-core.
• Ensure the error string is just the error message.

  • Bad:

    Error: something went wrong
      at Object.<anonymous> (/Users/username/repository/script.js:2:1)
      at Module._compile (node:internal/modules/cjs/loader:1159:14)
      at Module._extensions..js (node:internal/modules/cjs/loader:1213:10)
      at Module.load (node:internal/modules/cjs/loader:1037:32)
      at Module._load (node:internal/modules/cjs/loader:878:12)
      at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
      at node:internal/main/run_main_module:23:47

  • Good: Error: something went wrong.

• Ensure your configuration file (if applicable) is valid.
• If the issue is flaky (does not reproduce all the time), make sure 'Flaky' is checked.
• If the issue is not expected to error, make sure to write 'no error'.

Once the above checks are satisfied, please edit your issue with the changes and we will
try to reproduce the bug again.

---

Analyzer run

[OrKoN]

@jrandolf ptal, it is probably the new selector querying engine. I think 30-50% is too much so perhaps there is a bug (or generators are that much slower in Node just like ESM imports were last time).

[jrandolf]

This depends on how many elements are being queried. We typically batch queried elements with a default size of 20 which may be why this query takes so long (there are 120~ elements). I've amortized the logic related to this so the performance should be fixed. (It will still be about ~8-10% slower, but this is expected because of some new logic we've built into puppeteer)