Backport QueryBuilder performance patches #5
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Motivation: the query builder (and within it, replacePropertyNames and associated functions) is pretty CPU intensive. For our workload, it's one of the hottest functions in our entire stack. While improved in typeorm#4760, There are still outstanding issues relating to perf e.g. typeorm#3857 As we all know though, the first step in optimization is to measure systematically ;) https://wiki.c2.com/?ProfileBeforeOptimizing On my machine, this benchmark runs in ~3500ms or about 0.35ms/query. This tells us there's a way to go - on my stack, that's about 1/3 of a typical query's latency!
Context: the query builder is pretty CPU intensive, and can be slow - e.g. typeorm#3857 One of the things which makes this slow is `escapeRegExp` in the query builder: we freshly construct the same RegExp once per `replacePropertyName` invocation (many times per overall query!) and since the RegExp itself is constant -- we can lift it out and construct it once. Over-all this saves about 8% on our query build times as measured by typeorm#8955.
Digging further into typeorm#3857. See also typeorm#8955, typeorm#8956. As [previously discussed](typeorm#3857 (comment)), the query builder currently suffers from poor performance in two ways: quadratic numbers of operations with respect to total table/column counts, and poor constant factor performance (regexps can be expensive to build/run!) The constant-factor performance is the more tractable problem: no longer quadratically looping would be a chunky rewrite of the query builder, but we can locally refactor to be a bunch cheaper in terms of regexp operations. This change cuts the benchmark time here in ~half (yay!). We achieve this by simplifying the overall replacement regexp (we don't need our column names in there, since we already have a plain object where they're the keys to match against) so compilation of that is much cheaper, plus skipping the need to `escapeRegExp` every column as a result.
draaglom
approved these changes
Nov 14, 2022
| @@ -5,6 +5,9 @@ How to make changes to our fork: | |||
| - use the `loyaltylion/changes` branch | |||
| - while you're making changes, consider rebasing it on the latest typeorm master | |||
| - make your changes -- keep everything organised with good, isolated commits in case we want to cherry pick some of these commits to get them upstream later | |||
| - install dependencies | |||
| - some dependencies will not install when running on ARM, so we run it on a linux/amd64 container instead | |||
| - run `docker run -it --platform linux/amd64 -v ${PWD}:/app -w /app node:12 npm install` | |||
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Description of change
This cherry-picks @draaglom's QueryBuilder performance patches from the main repo into our fork.
Pull-Request Checklist
Original changes:
typeorm#8955
typeorm#8956
typeorm#9032
masterbranchnpm run formatto apply prettier formattingnpm run testpasses with this changeFixes #0000