perf : Optimize count distinct

[coderfender]

Which issue does this PR close?

Remove hashset based accumulators for smaller int data types and use bitmaps. Follow up of : #21453

• Closes Use bitmap for count_distinct expression for u8/16 and i8/16 [perf] #21488

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[coderfender]

benchmark results :

count_distinct i16 bitmap                      1.00      3.3±0.43µs        ? ?/sec    23.87    78.4±0.84µs        ? ?/sec
count_distinct i8 bitmap                       1.00      2.3±0.49µs        ? ?/sec    7.13     16.7±0.55µs        ? ?/sec
count_distinct u16 bitmap                      1.00      3.1±0.18µs        ? ?/sec    25.45    78.8±3.92µs        ? ?/sec
count_distinct u8 bitmap                       1.00      2.3±0.34µs        ? ?/sec    7.37     16.9±0.14µs        ? ?/sec

It seems like we are 25x faster for u16 bitmap based accumulators (or I am sleepy :) )

[Dandandan]

I think we can do the same for 16 bit types, it is just 65_536 bytes 8192 if we use a bitmap.

[Dandandan]

Oh wait, you're already doing that :)

[coderfender]

Query 0 in clickbench_extended dataset (which uses count distinct on u8 is now ~ 11 % faster :

┃ Query     ┃    main_cb ┃ bitmap_cb_2 ┃        Change ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━┩
│ QQuery 0  │  529.46 ms │   478.99 ms │ +1.11x faster │

(Other queries are faster but I believe that is more around variance )

┏━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┓
┃ Query     ┃    main_cb ┃ bitmap_cb_2 ┃        Change ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━┩
│ QQuery 0  │  529.46 ms │   478.99 ms │ +1.11x faster │
│ QQuery 1  │  107.43 ms │   102.59 ms │     no change │
│ QQuery 2  │  250.89 ms │   240.76 ms │     no change │
│ QQuery 3  │  207.67 ms │   207.49 ms │     no change │
│ QQuery 4  │  391.43 ms │   353.05 ms │ +1.11x faster │
│ QQuery 5  │ 4144.11 ms │  4084.08 ms │     no change │
│ QQuery 6  │  676.03 ms │   622.21 ms │ +1.09x faster │
│ QQuery 7  │  719.78 ms │   599.06 ms │ +1.20x faster │
│ QQuery 8  │  238.30 ms │   207.27 ms │ +1.15x faster │
│ QQuery 9  │ 1531.52 ms │  1406.34 ms │ +1.09x faster │
│ QQuery 10 │  435.27 ms │   403.28 ms │ +1.08x faster │
│ QQuery 11 │ 1043.68 ms │   955.22 ms │ +1.09x faster │
│ QQuery 12 │  113.16 ms │   106.31 ms │ +1.06x faster │
└───────────┴────────────┴─────────────┴───────────────┘
┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━┓
┃ Benchmark Summary          ┃            ┃
┡━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━┩
│ Total Time (main_cb)       │ 10388.73ms │
│ Total Time (bitmap_cb_2)   │  9766.66ms │
│ Average Time (main_cb)     │   799.13ms │
│ Average Time (bitmap_cb_2) │   751.28ms │
│ Queries Faster             │          9 │
│ Queries Slower             │          0 │
│ Queries with No Change     │          4 │
│ Queries with Failure       │          0 │
└────────────────────────────┴────────────┘

[coderfender]

cc : @neilconway , @alamb , @martin-g . Please take a look whenever you get a chance