bencyoung · HackerTrans

hace 2 mesesdiscuss

Unless your memory allocator runs a form of garbage collection, which most of the advanced ones do! Worst memory performance issue I've ever seen was in a C++ program where the deallocation of a large object graph from one spot completely trashed the performance of the application across many threads...

bencyoung

hace 4 mesesdiscuss

Sounds like the Chronophage clock in Cambridge: https://en.wikipedia.org/wiki/Corpus_Clock. It it's purely mechanical but has odd pauses in the ticks etc

bencyoung

hace 6 mesesdiscuss

Sorry for the delay! It's fairly simple. 1. You have a column on your objects you want secured as an LTREE[] 2. You add a GIST index on that column

The values should be the different hierarchy paths to access the object starting with a "type" e.g departments.root.deptA

When you run a query, depending on how you want to access you use a <@ query. E.g. I'm a user with root access to all depts "col <@ 'departments.root'::ltree" or I'm a user in dept A "col <@ 'departments.root.deptA'::ltree" etc

bencyoung

hace 6 mesesdiscuss

Sorry for the delay! It's fairly simple.

1. You have a column on your objects you want secured as an LTREE[] 2. You add a GIST index on that column

The values should be the different hierarchy paths to access the object starting with a "type" e.g departments.root.deptA

When you run a query, depending on how you want to access you use a <@ query. E.g. I'm a user with root access to all depts "col <@ 'departments.root'::ltree" or I'm a user in dept A "col <@ 'departments.root.deptA'::ltree" etc

bencyoung

hace 7 mesesdiscuss

If you're using Postgres then using the ltree module is great for permission systems. Available in RDS too

bencyoung

hace 8 mesesdiscuss

Not majorly odd, just an area I thought Rust would be hot on when it comes to performance...

bencyoung

hace 8 mesesdiscuss

Having worked in HPC a fair bit I'm not a fan of autovectorization. I prefer the compiled code's performance to be "unsuprising" based on the source and to use vectors etc where I know it's needed. I think in general it's better to have linting that points out performance issues (e.g. lift this outside the loop) rather than have compilers do it automatically and make things less predictable

bencyoung

hace 8 mesesdiscuss

Odd that c# has a better stable SIMD story than Rust! It has both generic vector types across a range of sizes and a good set of intrinsics across most of the common instruction sets

bencyoung

hace 8 mesesdiscuss

Cheapest MSK cluster is $100 a month and can easily run a dev/uat cluster with thousands of messages a second. They go up from there but we've made a lot of use of these and they are pretty useful

bencyoung

hace 8 mesesdiscuss

Kafka is great tech, never sure why people have an issue with it. Would I use it all the time? No, but where it's useful, it's really useful, and opens up whole patterns that are hard to implement other ways

bencyoung

hace 9 mesesdiscuss

JIT compilation can be faster for compiled languages too, as it allows data driven inlining and devirtualization, as well as "effective constant" propogation and runtime architecture feature detection

bencyoung

hace 10 mesesdiscuss

I think this is exactly the same approach PyPy used 15 or so years ago! Partially evaluate the language runtime

bencyoung

hace 10 mesesdiscuss

I almost did a PhD with David but ended up working at Transversal instead, which was a company he co-founded to do some interesting work in the search engine space! It's what got me into software development as a career so I'm always grateful to him

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