Better row group size in push_to_hub
Opened by lhoestq (closed)

This is a very simple change that improves `to_parquet` to use a more reasonable row group size for image and audio datasets.

This is especially useful for `push_to_hub` and will provide a better experience with the dataset viewer on HF

Comments:
<details>
<summary>Show benchmarks</summary>

PyArrow==8.0.0

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.007489 / 0.011353 (-0.003864) | 0.004914 / 0.011008 (-0.006095) | 0.111626 / 0.038508 (0.073117) | 0.037920 / 0.023109 (0.014811) | 0.350571 / 0.275898 (0.074673) | 0.389667 / 0.323480 (0.066187) | 0.006309 / 0.007986 (-0.001676) | 0.005488 / 0.004328 (0.001160) | 0.083962 / 0.004250 (0.079712) | 0.050728 / 0.037052 (0.013675) | 0.360997 / 0.258489 (0.102508) | 0.392736 / 0.293841 (0.098895) | 0.031975 / 0.128546 (-0.096571) | 0.009941 / 0.075646 (-0.065705) | 0.379840 / 0.419271 (-0.039432) | 0.056522 / 0.043533 (0.012989) | 0.359379 / 0.255139 (0.104240) | 0.384487 / 0.283200 (0.101287) | 0.117523 / 0.141683 (-0.024160) | 1.683639 / 1.452155 (0.231485) | 1.791645 / 1.492716 (0.298929) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.236862 / 0.018006 (0.218856) | 0.481208 / 0.000490 (0.480719) | 0.007455 / 0.000200 (0.007255) | 0.000111 / 0.000054 (0.000057) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.030854 / 0.037411 (-0.006557) | 0.126892 / 0.014526 (0.112367) | 0.139207 / 0.176557 (-0.037350) | 0.206447 / 0.737135 (-0.530689) | 0.143095 / 0.296338 (-0.153244) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.474677 / 0.215209 (0.259468) | 4.699534 / 2.077655 (2.621879) | 2.152102 / 1.504120 (0.647983) | 1.934815 / 1.541195 (0.393620) | 1.986448 / 1.468490 (0.517958) | 0.607184 / 4.584777 (-3.977593) | 4.480385 / 3.745712 (0.734673) | 2.074729 / 5.269862 (-3.195132) | 1.182383 / 4.565676 (-3.383294) | 0.075624 / 0.424275 (-0.348651) | 0.014046 / 0.007607 (0.006439) | 0.598859 / 0.226044 (0.372814) | 5.959551 / 2.268929 (3.690622) | 2.700851 / 55.444624 (-52.743773) | 2.303775 / 6.876477 (-4.572702) | 2.456441 / 2.142072 (0.314369) | 0.747185 / 4.805227 (-4.058042) | 0.165787 / 6.500664 (-6.334878) | 0.075817 / 0.075469 (0.000348) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.411859 / 1.841788 (-0.429928) | 17.375495 / 8.074308 (9.301187) | 15.187098 / 10.191392 (4.995706) | 0.169953 / 0.680424 (-0.510471) | 0.020204 / 0.534201 (-0.513997) | 0.461424 / 0.579283 (-0.117859) | 0.494443 / 0.434364 (0.060080) | 0.544583 / 0.540337 (0.004246) | 0.648231 / 1.386936 (-0.738705) |

</details>
PyArrow==latest

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.007785 / 0.011353 (-0.003568) | 0.005314 / 0.011008 (-0.005694) | 0.087273 / 0.038508 (0.048765) | 0.037810 / 0.023109 (0.014701) | 0.425473 / 0.275898 (0.149575) | 0.459976 / 0.323480 (0.136497) | 0.007270 / 0.007986 (-0.000716) | 0.004631 / 0.004328 (0.000303) | 0.087063 / 0.004250 (0.082812) | 0.052630 / 0.037052 (0.015578) | 0.432384 / 0.258489 (0.173895) | 0.500291 / 0.293841 (0.206450) | 0.033144 / 0.128546 (-0.095402) | 0.010101 / 0.075646 (-0.065545) | 0.096068 / 0.419271 (-0.323204) | 0.062750 / 0.043533 (0.019217) | 0.419308 / 0.255139 (0.164169) | 0.437099 / 0.283200 (0.153900) | 0.122289 / 0.141683 (-0.019394) | 1.737829 / 1.452155 (0.285674) | 1.851481 / 1.492716 (0.358765) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.014277 / 0.018006 (-0.003729) | 0.489835 / 0.000490 (0.489345) | 0.008423 / 0.000200 (0.008223) | 0.000188 / 0.000054 (0.000134) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.032966 / 0.037411 (-0.004445) | 0.130069 / 0.014526 (0.115544) | 0.144372 / 0.176557 (-0.032185) | 0.200400 / 0.737135 (-0.536735) | 0.149384 / 0.296338 (-0.146954) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.511542 / 0.215209 (0.296333) | 5.093879 / 2.077655 (3.016225) | 2.572088 / 1.504120 (1.067968) | 2.339118 / 1.541195 (0.797923) | 2.441637 / 1.468490 (0.973147) | 0.614818 / 4.584777 (-3.969959) | 4.724441 / 3.745712 (0.978729) | 5.431978 / 5.269862 (0.162116) | 2.257794 / 4.565676 (-2.307883) | 0.078109 / 0.424275 (-0.346166) | 0.013821 / 0.007607 (0.006214) | 0.639232 / 0.226044 (0.413188) | 6.424623 / 2.268929 (4.155694) | 3.163018 / 55.444624 (-52.281606) | 2.756786 / 6.876477 (-4.119690) | 2.808655 / 2.142072 (0.666583) | 0.745843 / 4.805227 (-4.059385) | 0.165562 / 6.500664 (-6.335102) | 0.076610 / 0.075469 (0.001141) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.738630 / 1.841788 (-0.103158) | 18.073573 / 8.074308 (9.999265) | 16.482820 / 10.191392 (6.291428) | 0.213233 / 0.680424 (-0.467191) | 0.022839 / 0.534201 (-0.511362) | 0.487043 / 0.579283 (-0.092240) | 0.512518 / 0.434364 (0.078154) | 0.549365 / 0.540337 (0.009028) | 0.656612 / 1.386936 (-0.730324) |

</details>
</details>

![](https://cml.dev/watermark.png#288e92b03bd4ec91c10c8a529b32631cfaba9fb7 "CML watermark")


Good idea!

I was wondering: if we want to optimize the balance between the size of downloading a row group, and the number of rows in the group, would it make sense to compute the row group size by checking the average size of the rows?

eg. 32x32 images could have a larger row group size than full HD images, no? Relying on the size would even remove the need to check the column types.

(in this proposal, we could use the computed row group size, eg 837, or use the nearest row group size in a list of values: 10, 100, 1000, 10000)

Probably, but I would go for a simpler solution first :p

Sure! I wanted to understand if the idea made sense or not, but it's not for this PR.

I think it will be more useful for people who use the viewer and won't impact sequential io that much.

DuckDB [paragraph](https://duckdb.org/docs/data/parquet/tips.html#selecting-a-row_group_size) that explains how to choose the `row_group_size`. Our default shard size is 500 MB in `push_to_hub`, so, ideally, we should aim for 64 MB row groups (and make this part configurable for power users 🙂).

So, before merging this PR, let's add a TODO or open an issue as a reminder that this can be improved.

I moved the config values, improved the features check and mentioned the improvements we could do in the docstring :)

_The documentation is not available anymore as the PR was closed or merged._

<details>
<summary>Show benchmarks</summary>

PyArrow==8.0.0

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.006211 / 0.011353 (-0.005141) | 0.004244 / 0.011008 (-0.006764) | 0.097941 / 0.038508 (0.059433) | 0.028564 / 0.023109 (0.005455) | 0.299651 / 0.275898 (0.023753) | 0.340694 / 0.323480 (0.017214) | 0.005161 / 0.007986 (-0.002824) | 0.004764 / 0.004328 (0.000435) | 0.075505 / 0.004250 (0.071255) | 0.039656 / 0.037052 (0.002603) | 0.309242 / 0.258489 (0.050753) | 0.350783 / 0.293841 (0.056942) | 0.025145 / 0.128546 (-0.103401) | 0.008498 / 0.075646 (-0.067148) | 0.317657 / 0.419271 (-0.101615) | 0.043926 / 0.043533 (0.000394) | 0.305915 / 0.255139 (0.050776) | 0.331630 / 0.283200 (0.048430) | 0.088564 / 0.141683 (-0.053119) | 1.533175 / 1.452155 (0.081021) | 1.581017 / 1.492716 (0.088301) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.206032 / 0.018006 (0.188025) | 0.433446 / 0.000490 (0.432956) | 0.003955 / 0.000200 (0.003755) | 0.000095 / 0.000054 (0.000040) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.023468 / 0.037411 (-0.013943) | 0.103292 / 0.014526 (0.088766) | 0.107234 / 0.176557 (-0.069322) | 0.168525 / 0.737135 (-0.568610) | 0.113218 / 0.296338 (-0.183120) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.431085 / 0.215209 (0.215875) | 4.302082 / 2.077655 (2.224427) | 2.068290 / 1.504120 (0.564171) | 1.850718 / 1.541195 (0.309523) | 1.964261 / 1.468490 (0.495771) | 0.547562 / 4.584777 (-4.037215) | 3.410739 / 3.745712 (-0.334974) | 1.779640 / 5.269862 (-3.490221) | 1.005466 / 4.565676 (-3.560210) | 0.066250 / 0.424275 (-0.358025) | 0.011877 / 0.007607 (0.004270) | 0.525185 / 0.226044 (0.299141) | 5.234786 / 2.268929 (2.965857) | 2.398045 / 55.444624 (-53.046580) | 2.073020 / 6.876477 (-4.803457) | 2.210753 / 2.142072 (0.068680) | 0.654897 / 4.805227 (-4.150331) | 0.134639 / 6.500664 (-6.366025) | 0.067050 / 0.075469 (-0.008419) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.180210 / 1.841788 (-0.661577) | 13.613091 / 8.074308 (5.538783) | 13.441837 / 10.191392 (3.250445) | 0.146048 / 0.680424 (-0.534376) | 0.016505 / 0.534201 (-0.517696) | 0.363210 / 0.579283 (-0.216073) | 0.405484 / 0.434364 (-0.028880) | 0.428712 / 0.540337 (-0.111625) | 0.522300 / 1.386936 (-0.864636) |

</details>
PyArrow==latest

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.006147 / 0.011353 (-0.005206) | 0.004161 / 0.011008 (-0.006847) | 0.075861 / 0.038508 (0.037353) | 0.027948 / 0.023109 (0.004839) | 0.362466 / 0.275898 (0.086568) | 0.398227 / 0.323480 (0.074747) | 0.005014 / 0.007986 (-0.002972) | 0.004772 / 0.004328 (0.000444) | 0.075674 / 0.004250 (0.071423) | 0.039158 / 0.037052 (0.002106) | 0.363567 / 0.258489 (0.105078) | 0.410378 / 0.293841 (0.116537) | 0.025510 / 0.128546 (-0.103036) | 0.008528 / 0.075646 (-0.067118) | 0.081803 / 0.419271 (-0.337468) | 0.040954 / 0.043533 (-0.002579) | 0.358492 / 0.255139 (0.103353) | 0.381345 / 0.283200 (0.098145) | 0.092347 / 0.141683 (-0.049336) | 1.567695 / 1.452155 (0.115540) | 1.668412 / 1.492716 (0.175696) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.203367 / 0.018006 (0.185360) | 0.424642 / 0.000490 (0.424152) | 0.002451 / 0.000200 (0.002251) | 0.000071 / 0.000054 (0.000017) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.026129 / 0.037411 (-0.011282) | 0.102564 / 0.014526 (0.088039) | 0.110583 / 0.176557 (-0.065973) | 0.164332 / 0.737135 (-0.572804) | 0.115706 / 0.296338 (-0.180632) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.468925 / 0.215209 (0.253716) | 4.657266 / 2.077655 (2.579612) | 2.423280 / 1.504120 (0.919160) | 2.236284 / 1.541195 (0.695089) | 2.323019 / 1.468490 (0.854529) | 0.548120 / 4.584777 (-4.036657) | 3.455602 / 3.745712 (-0.290110) | 1.730421 / 5.269862 (-3.539441) | 1.006089 / 4.565676 (-3.559588) | 0.067478 / 0.424275 (-0.356797) | 0.011465 / 0.007607 (0.003857) | 0.574235 / 0.226044 (0.348190) | 5.744404 / 2.268929 (3.475475) | 2.882225 / 55.444624 (-52.562400) | 2.618246 / 6.876477 (-4.258231) | 2.642920 / 2.142072 (0.500847) | 0.661441 / 4.805227 (-4.143787) | 0.137358 / 6.500664 (-6.363306) | 0.070372 / 0.075469 (-0.005097) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.333815 / 1.841788 (-0.507973) | 14.689667 / 8.074308 (6.615359) | 14.362294 / 10.191392 (4.170902) | 0.152011 / 0.680424 (-0.528413) | 0.016869 / 0.534201 (-0.517332) | 0.370433 / 0.579283 (-0.208851) | 0.399642 / 0.434364 (-0.034722) | 0.433759 / 0.540337 (-0.106578) | 0.525443 / 1.386936 (-0.861493) |

</details>
</details>

![](https://cml.dev/watermark.png#09e9f9a88edd9055b5c540e3d83b5a11d48f8ba8 "CML watermark")


<details>
<summary>Show benchmarks</summary>

PyArrow==8.0.0

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.006564 / 0.011353 (-0.004789) | 0.004350 / 0.011008 (-0.006658) | 0.096277 / 0.038508 (0.057769) | 0.032956 / 0.023109 (0.009847) | 0.303675 / 0.275898 (0.027777) | 0.336384 / 0.323480 (0.012904) | 0.005789 / 0.007986 (-0.002197) | 0.003957 / 0.004328 (-0.000371) | 0.073990 / 0.004250 (0.069740) | 0.050974 / 0.037052 (0.013922) | 0.321754 / 0.258489 (0.063265) | 0.349489 / 0.293841 (0.055648) | 0.031138 / 0.128546 (-0.097409) | 0.009000 / 0.075646 (-0.066646) | 0.325445 / 0.419271 (-0.093826) | 0.070173 / 0.043533 (0.026640) | 0.304706 / 0.255139 (0.049567) | 0.321803 / 0.283200 (0.038603) | 0.109405 / 0.141683 (-0.032278) | 1.489812 / 1.452155 (0.037657) | 1.577729 / 1.492716 (0.085013) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.287187 / 0.018006 (0.269181) | 0.527625 / 0.000490 (0.527135) | 0.006533 / 0.000200 (0.006333) | 0.000090 / 0.000054 (0.000036) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.026659 / 0.037411 (-0.010752) | 0.106236 / 0.014526 (0.091710) | 0.118615 / 0.176557 (-0.057941) | 0.173156 / 0.737135 (-0.563979) | 0.122883 / 0.296338 (-0.173456) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.407189 / 0.215209 (0.191980) | 4.055732 / 2.077655 (1.978078) | 1.865594 / 1.504120 (0.361474) | 1.664325 / 1.541195 (0.123130) | 1.668961 / 1.468490 (0.200471) | 0.521207 / 4.584777 (-4.063570) | 3.740424 / 3.745712 (-0.005288) | 3.431973 / 5.269862 (-1.837889) | 1.636669 / 4.565676 (-2.929008) | 0.065271 / 0.424275 (-0.359005) | 0.012151 / 0.007607 (0.004544) | 0.514233 / 0.226044 (0.288189) | 5.110150 / 2.268929 (2.841222) | 2.264340 / 55.444624 (-53.180284) | 1.940428 / 6.876477 (-4.936049) | 2.042286 / 2.142072 (-0.099787) | 0.639200 / 4.805227 (-4.166028) | 0.139537 / 6.500664 (-6.361127) | 0.063195 / 0.075469 (-0.012274) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.179501 / 1.841788 (-0.662286) | 14.600133 / 8.074308 (6.525825) | 14.902137 / 10.191392 (4.710745) | 0.144509 / 0.680424 (-0.535915) | 0.017449 / 0.534201 (-0.516752) | 0.393135 / 0.579283 (-0.186148) | 0.413103 / 0.434364 (-0.021261) | 0.459897 / 0.540337 (-0.080440) | 0.552602 / 1.386936 (-0.834334) |

</details>
PyArrow==latest

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.006891 / 0.011353 (-0.004462) | 0.004633 / 0.011008 (-0.006375) | 0.073093 / 0.038508 (0.034585) | 0.032509 / 0.023109 (0.009399) | 0.348332 / 0.275898 (0.072434) | 0.381920 / 0.323480 (0.058440) | 0.005978 / 0.007986 (-0.002007) | 0.005360 / 0.004328 (0.001032) | 0.074307 / 0.004250 (0.070056) | 0.049668 / 0.037052 (0.012615) | 0.354713 / 0.258489 (0.096224) | 0.398521 / 0.293841 (0.104681) | 0.032013 / 0.128546 (-0.096534) | 0.008890 / 0.075646 (-0.066756) | 0.080013 / 0.419271 (-0.339259) | 0.051820 / 0.043533 (0.008288) | 0.349730 / 0.255139 (0.094591) | 0.369267 / 0.283200 (0.086067) | 0.103874 / 0.141683 (-0.037809) | 1.484148 / 1.452155 (0.031993) | 1.573927 / 1.492716 (0.081211) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.009699 / 0.018006 (-0.008307) | 0.511176 / 0.000490 (0.510686) | 0.002938 / 0.000200 (0.002738) | 0.000109 / 0.000054 (0.000054) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.027847 / 0.037411 (-0.009564) | 0.111565 / 0.014526 (0.097039) | 0.120625 / 0.176557 (-0.055932) | 0.172130 / 0.737135 (-0.565006) | 0.125949 / 0.296338 (-0.170389) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.430634 / 0.215209 (0.215424) | 4.315377 / 2.077655 (2.237722) | 2.070764 / 1.504120 (0.566644) | 1.881962 / 1.541195 (0.340767) | 1.904053 / 1.468490 (0.435563) | 0.524973 / 4.584777 (-4.059804) | 3.718359 / 3.745712 (-0.027353) | 3.415344 / 5.269862 (-1.854518) | 1.224568 / 4.565676 (-3.341108) | 0.065593 / 0.424275 (-0.358682) | 0.011643 / 0.007607 (0.004036) | 0.537050 / 0.226044 (0.311006) | 5.352155 / 2.268929 (3.083226) | 2.557361 / 55.444624 (-52.887263) | 2.217770 / 6.876477 (-4.658707) | 2.194975 / 2.142072 (0.052902) | 0.635142 / 4.805227 (-4.170085) | 0.140642 / 6.500664 (-6.360022) | 0.064690 / 0.075469 (-0.010779) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 1.266125 / 1.841788 (-0.575663) | 14.836413 / 8.074308 (6.762105) | 14.446870 / 10.191392 (4.255478) | 0.191545 / 0.680424 (-0.488878) | 0.017433 / 0.534201 (-0.516768) | 0.392296 / 0.579283 (-0.186987) | 0.420698 / 0.434364 (-0.013666) | 0.463225 / 0.540337 (-0.077112) | 0.556127 / 1.386936 (-0.830809) |

</details>
</details>

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