GenericSchema::schemaMap_ is not a map and leads to O(n) complexity

[svart-riddare]

Upon investigation of performance issues, we found out that GenericSchema::schemaMap_ is a linear type container and thus methods GenericSchema::GetSchema() and GenericSchema::GetPointer() have O(n) complexity, yielding a huge performance impact on our application.

[aikawayataro]

This is indeed a map. Map (associative array/dictionary, etc.) has no implementation constraints. A map with a hash table is probably what you want to see.
But I suspect that nothing is going to change. Are you really able to confirm that GetPointer is the culprit for the performance issues?

[svart-riddare]

You are right, my wording was not precise enough, by map I meant "efficient" map !

Yes, I used the perf tool to confirm that more than 60% of the time was spent in those functions; I bluntly inserted a std::map for GenericSchema::schemaMap_ and I got a x3 speedup and those functions disappeared from perf report.

[aikawayataro]

If it's 60% of a large complex application, it's certainly a problem.
I believe you can implement your own SchemaDocument using the reference implementation but with std::map or std::hash_map. Or you can just patch the code :) .

[svart-riddare]

Yes, that's what I did; there's no release/tag of rapidjson since 2016 anyway. I opened a ticket to let other know.