Don't include pure object fields in ZQuery collection

[kyri-petrou]

As discussed on Discord, I gave this a go. Seems to offer a fairly good performance increase whenever we have a mix of pure and effectful fields.

series/2.x:

[info] Benchmark                                           Mode  Cnt    Score   Error  Units
[info] NestedZQueryBenchmark.multifieldBatchedQuery1000   thrpt    5  551.735 ± 8.117  ops/s
[info] NestedZQueryBenchmark.multifieldBatchedQuery10000  thrpt    5   45.115 ± 1.188  ops/s

PR:

[info] Benchmark                                           Mode  Cnt    Score   Error  Units
[info] NestedZQueryBenchmark.multifieldBatchedQuery1000   thrpt    5  633.503 ± 8.756  ops/s
[info] NestedZQueryBenchmark.multifieldBatchedQuery10000  thrpt    5   54.862 ± 0.919  ops/s

I also did some rough testing for cases that we don't have any pure fields, and it seems that the performance was roughly identical to what we had previously

[ghostdogpr]

It looks good!

I have one concern though (which is more general, and could be address in other PRs): we are adding more and more "optimized" code using mutable collections and so on, and I think it makes the code harder to read. I think it would be good to move this kind of code to dedicated functions so that the main "flow" stays short and readable. What do you think?

[kyri-petrou]

It looks good!

I have one concern though (which is more general, and could be address in other PRs): we are adding more and more "optimized" code using mutable collections and so on, and I think it makes the code harder to read. I think it would be good to move this kind of code to dedicated functions so that the main "flow" stays short and readable. What do you think?

Yeah I agree. I'll do it in a followup PR in a bit 👍