jsoniter VS GJSON

Since most of the time would be spent decoding json, you could try to cut this time using https://github.com/bytedance/sonic or https://github.com/json-iterator/go, both are drop-in replacements for the stdlib, sonic is faster.

We all know the builtin golang JSON parser is slow.

How about doing comparisons against other implementations?

Like this one: https://github.com/json-iterator/go

Json-iterator (https://github.com/json-iterator/go), you can replace all of encoding/json with this. It does the same thing but it's faster.

Do you want to look at every field all at the same time? If not, you can pick out individual fields. There's other packages such as https://github.com/tidwall/gjson or https://github.com/json-iterator/go that let you pass in paths such as "a.b.c" to extract single fields.

For each Go type used within the config, we generate a separate unmarshaller function. The unmarshallers use json-iterator to process the output from CUE, while tracking the path within the config to the unmarshalled value. This path tracking will allow the function to check if live overrides have been provided on that path and return the override instead.

https://github.com/json-iterator/go an alternative JSON encoding package which allows to stream (flush out) encoded data as soon as it's able to (which is in contrast with the stock package which buffers everything until the encoding is known to be complete and OK).

What to use Easyjson is about the top of the pack and it's straightforward. The downside of efficient tools is that they use code generation to create the code required to turn your structs into json to minimise allocations. This is a manual build step which is annoying. Interestingly json-iterator also uses reflection but it's significantly faster. I suspect black magic.

jsoniter for low level access to JSON encode and decode

Takes like 10 minutes to write and parses very efficiently. https://github.com/json-iterator/go looks like it can provide such simple parsing

Someone made a benchmark of serialization libraries in go [1], and I was surprised to see gobs is one of the slowest ones, specially for decoding. I suspect part of the reason is that the API doesn't not allow reusing decoders [2]. From my explorations it seems like both JSON [3], message-pack [4] and CBOR [5] are better alternatives.

By the way, in Go there are a like a million JSON encoders because a lot of things in the std library are not really coded for maximum performance but more for easy of usage, it seems. Perhaps this is the right balance for certain things (ex: the http library, see [6]).

There are also a bunch of libraries that allow you to modify a JSON file "in place", without having to fully deserialize into structs (ex: GJSON/SJSON [7] [8]). This sounds very convenient and more efficient that fully de/serializing if we just need to change the data a little.

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1: https://github.com/alecthomas/go_serialization_benchmarks

2: https://github.com/golang/go/issues/29766#issuecomment-45492...

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3: https://github.com/goccy/go-json

4: https://github.com/vmihailenco/msgpack

5: https://github.com/fxamacker/cbor

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6: https://github.com/valyala/fasthttp#faq

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7: https://github.com/tidwall/gjson

8: https://github.com/tidwall/sjson

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I don't think there is a way to sort an array, though. However, there is an option to have keys sorted. Personally, I don't think there is much annoyance in that. One could just pipe `jj` output to `sort | uniq -c`.

[0]: https://github.com/tidwall/gjson/blob/master/SYNTAX.md

I’m using GJSON, so far so good!

If the fields you need are just a small subset of the whole json, maybe https://github.com/tidwall/gjson might be of use to read only those (using jsonpath) without needing to create complete corresponding structs.

Thank you for the reminder, it's never too much of it :) Didn't say it, but the code was pprof-iled many times and i can really say it's well optimized. I use own libraries with on-the-fly equations (sums, avgs, emas, stds, ...) wherever possible and also made custom json parser as json messages are in fixed format, so the parser is about 10x faster than gjson. I optimized it to the point that I avoided using maps, and rather iterate via slice where ever possible.

You are right, for learning purposes this fit my needs, but I can imagine an approach similar to this repo: https://github.com/tidwall/gjson

https://github.com/tidwall/gjson is a relatively sensible library if this is something you need to deal with and the structure is actually unknowable.