chore: add mem test for big values and default the flag

[kostasrim]

• default serialization_max_chunk_size to 10 mb
• add test for big values
• small rename of enum to conform style guide

[chakaz]

Suggested change

	enum class ChunkState { kFlushMidEntry, kFlushEndEntry };
	enum class FlushState { kFlushMidEntry, kFlushEndEntry };

wdyt?

[chakaz]

This value is named oddly. ten_mb means 10 mega bytes? Because it has a value of 125k, so what is that about? 🤣

[kostasrim]

Ten megabits! Suggest a rename and I will do it!

[chakaz]

I still don't follow.. what is this number? 10 megabits is 10*2^20, which is 10485760. It's also not the number of bytes in 10 megabits.
And also, why do we care about bits here? 🤣

[chakaz]

ditto

[chakaz]

I'd take the current RSS value, and add (say) 100mb to it as a threshold.
This way the test will be more robust to unrelated, general changes in Dragonfly's memory

[chakaz]

Ideally, we would have a version of this test per each supported data type
Would that be hard?

[kostasrim]

not really, I will make them part of this test. It's a few more lines -- I will just be explicit -- no fancy abstractions 🤓

[chakaz]

lol this is 100k no?

[chakaz]

and this is 100mb, no?

[chakaz]

Bloom filters are of a constant size, no? (i.e. it doesn't matter how many times you add to them, they can't and won't grow in memory usage)

[kostasrim]

not if you specify expansion policy which we do not yet support

[chakaz]

I didn't realize bloom filters can be expanded. I thought they can't (I don't understand how)
Anyway, I think you can remove these comments and don't test (and don't support) bloom filters