Serialize tags/metrics in a single pass #1416
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andrewlock
approved these changes
Apr 20, 2021
lucaspimentel
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Apr 20, 2021
zacharycmontoya
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Apr 20, 2021
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Tags and metrics were initially serialized in a single pass, and the count was back-patched at the end. This caused issues because the MessagePack map header has a variable size, so in some cases I ended up not allocating enough space. This was fixed by switching to a two-pass algorithm, with a performance hit: #996
I just realized that there's actually an API to write a fixed-size header, so I'm switching back to a single-pass algorithm. The existing unit test
TagsListTests.Serializationverifies that it does not introduce any regression (I confirmed beforehand that the test still fails if I useMessagePackBinary.WriteMapHeaderinstead ofMessagePackBinary.WriteMapHeaderForceMap32Block).