gob fairness about go_serialization_benchmarks HOT 7 CLOSED

I agree with @robzan8. It make a misunderstanding on Gob. Gob is the same fast as protobuf in my tests.

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I'd welcome a PR for this. I tried, but kept getting corrupt message errors:

BenchmarkGobMarshal-8    1000000          1207 ns/op          48 B/op          2 allocs/op
BenchmarkGobUnmarshal-8 b=61
--- FAIL: BenchmarkGobUnmarshal-8
    serialization_benchmarks_test.go:114: gob failed to unmarshal: gob: unknown type id or corrupted data (<��b9b2b4faa77947cf�4���IL�
        1ca61f574b��Y�K���?)
ok      github.com/alecthomas/go_serialization_benchmarks   1.244s

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I'm pretty sure I understand where the issue comes from.
The first time a gob encoder encodes a value of a certain type that has never encountered before, it also transmits type information needed by the decoder for that type.
in function benchUnmarshal, ser[0] also contains serialized type info that is needed to decode elements of type A. So, for everything to work correctly, ser[0] should be the first thing decoded by the decoder.
Unfortunately, the decoder chooses at random what to decode, and it reports that a value with unknown type id has been encountered.
To fix the problem, ser[0] should be decoded only once, before anything else (before some other ser[i]). Another thing that may work is calling gob.Register(a) (where "a" is a value of type A), before doing the encoding/decoding (former method works for sure, I'm not sure about the latter).
I may be able to do a PR in the next few days.

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I can't run the benchmarks on master because zombiezen.com/go/capnproto2 has been moved.
I tried go-getting https://github.com/zombiezen/go-capnproto2
but I get the following error:
can't load package: package github.com/zombiezen/go-capnproto2: code in directory $GOPATH/src/github.com/zombiezen/go-capnproto2 expects import "zombiezen.com/go/capnproto2"

Am I missing something?

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zombiezen.com/go/capnproto2 uses a go-import meta redirect, so it should still work. It works for me:

[alec@cavern:~/Projects/go_serialization_benchmarks]go get -u zombiezen.com/go/capnproto2
[alec@cavern:~/Projects/go_serialization_benchmarks]

PS. Did you try using the Makefile? make clean && make install && make

from go_serialization_benchmarks.

zombiezen.com/go/capnproto2 was down yesterday when I tried; works now.

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Before first use you to gob.Register. That's where the errors came from.

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