Title: Create DatasetNotFoundError and DataFilesNotFoundError
State: closed

Create `DatasetNotFoundError` and `DataFilesNotFoundError`.

Fix #6397.

CC: @severo 

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) | 0.004459 / 0.011353 (-0.006894) | 0.002883 / 0.011008 (-0.008125) | 0.062434 / 0.038508 (0.023925) | 0.030353 / 0.023109 (0.007244) | 0.256696 / 0.275898 (-0.019202) | 0.280557 / 0.323480 (-0.042923) | 0.003903 / 0.007986 (-0.004083) | 0.002424 / 0.004328 (-0.001905) | 0.048509 / 0.004250 (0.044259) | 0.043583 / 0.037052 (0.006531) | 0.253900 / 0.258489 (-0.004590) | 0.309146 / 0.293841 (0.015305) | 0.023253 / 0.128546 (-0.105294) | 0.007073 / 0.075646 (-0.068573) | 0.204118 / 0.419271 (-0.215154) | 0.056429 / 0.043533 (0.012897) | 0.247331 / 0.255139 (-0.007808) | 0.271581 / 0.283200 (-0.011619) | 0.017021 / 0.141683 (-0.124662) | 1.115057 / 1.452155 (-0.337098) | 1.209947 / 1.492716 (-0.282770) |

### 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) | 0.093141 / 0.018006 (0.075134) | 0.295987 / 0.000490 (0.295497) | 0.000221 / 0.000200 (0.000021) | 0.000048 / 0.000054 (-0.000006) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.019182 / 0.037411 (-0.018230) | 0.062049 / 0.014526 (0.047523) | 0.073824 / 0.176557 (-0.102733) | 0.120175 / 0.737135 (-0.616960) | 0.074700 / 0.296338 (-0.221639) |

### 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) | 0.280036 / 0.215209 (0.064827) | 2.731512 / 2.077655 (0.653857) | 1.414606 / 1.504120 (-0.089514) | 1.302433 / 1.541195 (-0.238761) | 1.313012 / 1.468490 (-0.155478) | 0.399722 / 4.584777 (-4.185055) | 2.371249 / 3.745712 (-1.374463) | 2.582520 / 5.269862 (-2.687342) | 1.558505 / 4.565676 (-3.007171) | 0.045765 / 0.424275 (-0.378510) | 0.004748 / 0.007607 (-0.002859) | 0.327623 / 0.226044 (0.101578) | 3.258742 / 2.268929 (0.989814) | 1.756798 / 55.444624 (-53.687826) | 1.494551 / 6.876477 (-5.381925) | 1.518161 / 2.142072 (-0.623911) | 0.468560 / 4.805227 (-4.336667) | 0.101034 / 6.500664 (-6.399630) | 0.048259 / 0.075469 (-0.027210) |

### 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) | 0.938146 / 1.841788 (-0.903642) | 11.636387 / 8.074308 (3.562078) | 10.638909 / 10.191392 (0.447517) | 0.128340 / 0.680424 (-0.552084) | 0.015194 / 0.534201 (-0.519007) | 0.275961 / 0.579283 (-0.303322) | 0.264629 / 0.434364 (-0.169735) | 0.308580 / 0.540337 (-0.231758) | 0.433658 / 1.386936 (-0.953278) |

</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) | 0.004797 / 0.011353 (-0.006556) | 0.002801 / 0.011008 (-0.008208) | 0.048101 / 0.038508 (0.009593) | 0.056406 / 0.023109 (0.033296) | 0.274966 / 0.275898 (-0.000932) | 0.298310 / 0.323480 (-0.025170) | 0.004115 / 0.007986 (-0.003871) | 0.002437 / 0.004328 (-0.001891) | 0.047921 / 0.004250 (0.043671) | 0.038812 / 0.037052 (0.001760) | 0.279594 / 0.258489 (0.021105) | 0.313703 / 0.293841 (0.019862) | 0.024485 / 0.128546 (-0.104061) | 0.007095 / 0.075646 (-0.068551) | 0.053398 / 0.419271 (-0.365874) | 0.032306 / 0.043533 (-0.011227) | 0.278014 / 0.255139 (0.022875) | 0.301156 / 0.283200 (0.017956) | 0.017353 / 0.141683 (-0.124330) | 1.150168 / 1.452155 (-0.301987) | 1.190822 / 1.492716 (-0.301894) |

### 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) | 0.092162 / 0.018006 (0.074156) | 0.301031 / 0.000490 (0.300541) | 0.000244 / 0.000200 (0.000044) | 0.000062 / 0.000054 (0.000008) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.020918 / 0.037411 (-0.016494) | 0.072030 / 0.014526 (0.057504) | 0.081813 / 0.176557 (-0.094743) | 0.120233 / 0.737135 (-0.616903) | 0.082874 / 0.296338 (-0.213465) |

### 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) | 0.291659 / 0.215209 (0.076450) | 2.841978 / 2.077655 (0.764323) | 1.594207 / 1.504120 (0.090087) | 1.473941 / 1.541195 (-0.067254) | 1.514393 / 1.468490 (0.045903) | 0.393393 / 4.584777 (-4.191384) | 2.443663 / 3.745712 (-1.302050) | 2.545747 / 5.269862 (-2.724114) | 1.521130 / 4.565676 (-3.044546) | 0.046246 / 0.424275 (-0.378030) | 0.004826 / 0.007607 (-0.002781) | 0.340909 / 0.226044 (0.114865) | 3.319474 / 2.268929 (1.050546) | 1.933110 / 55.444624 (-53.511515) | 1.662463 / 6.876477 (-5.214014) | 1.670331 / 2.142072 (-0.471742) | 0.458062 / 4.805227 (-4.347165) | 0.098397 / 6.500664 (-6.402267) | 0.041339 / 0.075469 (-0.034130) |

### 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) | 0.973718 / 1.841788 (-0.868070) | 12.095266 / 8.074308 (4.020957) | 10.761212 / 10.191392 (0.569820) | 0.142352 / 0.680424 (-0.538072) | 0.015423 / 0.534201 (-0.518778) | 0.270912 / 0.579283 (-0.308371) | 0.276618 / 0.434364 (-0.157746) | 0.309120 / 0.540337 (-0.231217) | 0.415330 / 1.386936 (-0.971606) |

</details>
</details>

![](https://cml.dev/watermark.png#cf4ba6f0e2641056774c01f62984aef5de5d68f1 "CML watermark")
_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) | 0.004676 / 0.011353 (-0.006677) | 0.003101 / 0.011008 (-0.007907) | 0.062260 / 0.038508 (0.023752) | 0.030012 / 0.023109 (0.006903) | 0.253704 / 0.275898 (-0.022194) | 0.276404 / 0.323480 (-0.047075) | 0.004060 / 0.007986 (-0.003926) | 0.002467 / 0.004328 (-0.001861) | 0.047921 / 0.004250 (0.043670) | 0.045760 / 0.037052 (0.008708) | 0.254529 / 0.258489 (-0.003960) | 0.286283 / 0.293841 (-0.007558) | 0.023301 / 0.128546 (-0.105246) | 0.007407 / 0.075646 (-0.068239) | 0.204541 / 0.419271 (-0.214730) | 0.056387 / 0.043533 (0.012854) | 0.252120 / 0.255139 (-0.003019) | 0.275795 / 0.283200 (-0.007404) | 0.018648 / 0.141683 (-0.123034) | 1.113484 / 1.452155 (-0.338671) | 1.168685 / 1.492716 (-0.324031) |

### 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) | 0.098286 / 0.018006 (0.080280) | 0.304619 / 0.000490 (0.304129) | 0.000225 / 0.000200 (0.000025) | 0.000058 / 0.000054 (0.000004) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.019183 / 0.037411 (-0.018229) | 0.062183 / 0.014526 (0.047657) | 0.074288 / 0.176557 (-0.102269) | 0.120576 / 0.737135 (-0.616560) | 0.074833 / 0.296338 (-0.221505) |

### 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) | 0.280512 / 0.215209 (0.065303) | 2.770052 / 2.077655 (0.692397) | 1.471234 / 1.504120 (-0.032886) | 1.352080 / 1.541195 (-0.189114) | 1.374518 / 1.468490 (-0.093973) | 0.407108 / 4.584777 (-4.177669) | 2.400581 / 3.745712 (-1.345131) | 2.677507 / 5.269862 (-2.592355) | 1.578042 / 4.565676 (-2.987635) | 0.048539 / 0.424275 (-0.375736) | 0.004905 / 0.007607 (-0.002703) | 0.346676 / 0.226044 (0.120631) | 3.367732 / 2.268929 (1.098803) | 1.844405 / 55.444624 (-53.600220) | 1.576883 / 6.876477 (-5.299594) | 1.666986 / 2.142072 (-0.475086) | 0.495872 / 4.805227 (-4.309355) | 0.103142 / 6.500664 (-6.397522) | 0.044037 / 0.075469 (-0.031432) |

### 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) | 0.980865 / 1.841788 (-0.860923) | 12.268525 / 8.074308 (4.194217) | 10.756554 / 10.191392 (0.565162) | 0.129954 / 0.680424 (-0.550470) | 0.013864 / 0.534201 (-0.520337) | 0.267653 / 0.579283 (-0.311630) | 0.265120 / 0.434364 (-0.169244) | 0.309050 / 0.540337 (-0.231288) | 0.423877 / 1.386936 (-0.963059) |

</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) | 0.005074 / 0.011353 (-0.006279) | 0.003001 / 0.011008 (-0.008007) | 0.048271 / 0.038508 (0.009763) | 0.061206 / 0.023109 (0.038097) | 0.279268 / 0.275898 (0.003370) | 0.302592 / 0.323480 (-0.020888) | 0.004177 / 0.007986 (-0.003809) | 0.002452 / 0.004328 (-0.001876) | 0.048259 / 0.004250 (0.044009) | 0.040032 / 0.037052 (0.002979) | 0.281398 / 0.258489 (0.022909) | 0.314121 / 0.293841 (0.020280) | 0.025137 / 0.128546 (-0.103409) | 0.007230 / 0.075646 (-0.068416) | 0.054537 / 0.419271 (-0.364735) | 0.033266 / 0.043533 (-0.010267) | 0.277305 / 0.255139 (0.022166) | 0.295993 / 0.283200 (0.012794) | 0.019278 / 0.141683 (-0.122405) | 1.131700 / 1.452155 (-0.320454) | 1.183848 / 1.492716 (-0.308868) |

### 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) | 0.092258 / 0.018006 (0.074251) | 0.310668 / 0.000490 (0.310178) | 0.000219 / 0.000200 (0.000019) | 0.000047 / 0.000054 (-0.000008) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.021838 / 0.037411 (-0.015574) | 0.071382 / 0.014526 (0.056857) | 0.081389 / 0.176557 (-0.095168) | 0.120389 / 0.737135 (-0.616746) | 0.084135 / 0.296338 (-0.212203) |

### 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) | 0.291676 / 0.215209 (0.076467) | 2.840623 / 2.077655 (0.762968) | 1.565748 / 1.504120 (0.061628) | 1.452529 / 1.541195 (-0.088666) | 1.490633 / 1.468490 (0.022143) | 0.402878 / 4.584777 (-4.181899) | 2.486192 / 3.745712 (-1.259520) | 2.520563 / 5.269862 (-2.749299) | 1.518550 / 4.565676 (-3.047127) | 0.047423 / 0.424275 (-0.376852) | 0.004823 / 0.007607 (-0.002784) | 0.353122 / 0.226044 (0.127078) | 3.452136 / 2.268929 (1.183208) | 1.973798 / 55.444624 (-53.470827) | 1.669569 / 6.876477 (-5.206907) | 1.654910 / 2.142072 (-0.487163) | 0.486746 / 4.805227 (-4.318481) | 0.097260 / 6.500664 (-6.403404) | 0.040608 / 0.075469 (-0.034861) |

### 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) | 0.989705 / 1.841788 (-0.852083) | 12.114386 / 8.074308 (4.040077) | 11.284551 / 10.191392 (1.093159) | 0.141408 / 0.680424 (-0.539016) | 0.015275 / 0.534201 (-0.518926) | 0.267407 / 0.579283 (-0.311877) | 0.281007 / 0.434364 (-0.153357) | 0.309617 / 0.540337 (-0.230720) | 0.414033 / 1.386936 (-0.972903) |

</details>
</details>

![](https://cml.dev/watermark.png#6f3f3e3feec9d7d4d36111401787eb7b5fd51836 "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) | 0.004888 / 0.011353 (-0.006465) | 0.002775 / 0.011008 (-0.008233) | 0.062000 / 0.038508 (0.023492) | 0.050694 / 0.023109 (0.027584) | 0.257063 / 0.275898 (-0.018835) | 0.282743 / 0.323480 (-0.040736) | 0.002862 / 0.007986 (-0.005124) | 0.002305 / 0.004328 (-0.002023) | 0.049549 / 0.004250 (0.045299) | 0.038754 / 0.037052 (0.001701) | 0.264047 / 0.258489 (0.005558) | 0.310162 / 0.293841 (0.016321) | 0.022901 / 0.128546 (-0.105645) | 0.006894 / 0.075646 (-0.068752) | 0.202467 / 0.419271 (-0.216805) | 0.035901 / 0.043533 (-0.007631) | 0.262344 / 0.255139 (0.007205) | 0.285563 / 0.283200 (0.002364) | 0.017070 / 0.141683 (-0.124613) | 1.113972 / 1.452155 (-0.338182) | 1.176261 / 1.492716 (-0.316455) |

### 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) | 0.092912 / 0.018006 (0.074906) | 0.302610 / 0.000490 (0.302120) | 0.000204 / 0.000200 (0.000005) | 0.000043 / 0.000054 (-0.000012) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.018232 / 0.037411 (-0.019179) | 0.062367 / 0.014526 (0.047841) | 0.074570 / 0.176557 (-0.101987) | 0.120468 / 0.737135 (-0.616668) | 0.075187 / 0.296338 (-0.221151) |

### 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) | 0.279760 / 0.215209 (0.064551) | 2.715372 / 2.077655 (0.637717) | 1.461636 / 1.504120 (-0.042484) | 1.324220 / 1.541195 (-0.216975) | 1.350724 / 1.468490 (-0.117766) | 0.395648 / 4.584777 (-4.189129) | 2.376548 / 3.745712 (-1.369164) | 2.594662 / 5.269862 (-2.675200) | 1.553528 / 4.565676 (-3.012148) | 0.047875 / 0.424275 (-0.376400) | 0.005287 / 0.007607 (-0.002321) | 0.334734 / 0.226044 (0.108689) | 3.294753 / 2.268929 (1.025825) | 1.797901 / 55.444624 (-53.646724) | 1.510907 / 6.876477 (-5.365570) | 1.536070 / 2.142072 (-0.606003) | 0.474672 / 4.805227 (-4.330555) | 0.099323 / 6.500664 (-6.401341) | 0.041703 / 0.075469 (-0.033766) |

### 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) | 0.947441 / 1.841788 (-0.894347) | 11.451378 / 8.074308 (3.377070) | 10.283213 / 10.191392 (0.091821) | 0.131032 / 0.680424 (-0.549392) | 0.014423 / 0.534201 (-0.519777) | 0.272568 / 0.579283 (-0.306715) | 0.267127 / 0.434364 (-0.167237) | 0.307361 / 0.540337 (-0.232976) | 0.403858 / 1.386936 (-0.983078) |

</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) | 0.004836 / 0.011353 (-0.006517) | 0.002544 / 0.011008 (-0.008464) | 0.047979 / 0.038508 (0.009471) | 0.052211 / 0.023109 (0.029102) | 0.273394 / 0.275898 (-0.002504) | 0.291202 / 0.323480 (-0.032277) | 0.004094 / 0.007986 (-0.003891) | 0.002415 / 0.004328 (-0.001914) | 0.048057 / 0.004250 (0.043807) | 0.039756 / 0.037052 (0.002703) | 0.277301 / 0.258489 (0.018812) | 0.297626 / 0.293841 (0.003785) | 0.024641 / 0.128546 (-0.103905) | 0.006957 / 0.075646 (-0.068690) | 0.053574 / 0.419271 (-0.365697) | 0.036532 / 0.043533 (-0.007001) | 0.273753 / 0.255139 (0.018614) | 0.294254 / 0.283200 (0.011054) | 0.022252 / 0.141683 (-0.119431) | 1.128609 / 1.452155 (-0.323546) | 1.217322 / 1.492716 (-0.275394) |

### 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) | 0.091050 / 0.018006 (0.073044) | 0.300089 / 0.000490 (0.299600) | 0.000215 / 0.000200 (0.000015) | 0.000045 / 0.000054 (-0.000010) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.021423 / 0.037411 (-0.015988) | 0.069892 / 0.014526 (0.055366) | 0.081125 / 0.176557 (-0.095432) | 0.118725 / 0.737135 (-0.618411) | 0.081357 / 0.296338 (-0.214981) |

### 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) | 0.295046 / 0.215209 (0.079837) | 2.868813 / 2.077655 (0.791159) | 1.579613 / 1.504120 (0.075493) | 1.449308 / 1.541195 (-0.091887) | 1.478804 / 1.468490 (0.010314) | 0.416916 / 4.584777 (-4.167861) | 2.461093 / 3.745712 (-1.284619) | 2.449792 / 5.269862 (-2.820070) | 1.573930 / 4.565676 (-2.991746) | 0.046808 / 0.424275 (-0.377467) | 0.004811 / 0.007607 (-0.002796) | 0.352805 / 0.226044 (0.126761) | 3.495034 / 2.268929 (1.226105) | 1.952019 / 55.444624 (-53.492606) | 1.642607 / 6.876477 (-5.233869) | 1.775235 / 2.142072 (-0.366837) | 0.482196 / 4.805227 (-4.323032) | 0.099562 / 6.500664 (-6.401102) | 0.040709 / 0.075469 (-0.034760) |

### 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) | 0.972750 / 1.841788 (-0.869038) | 11.905172 / 8.074308 (3.830864) | 10.613847 / 10.191392 (0.422455) | 0.129892 / 0.680424 (-0.550532) | 0.015611 / 0.534201 (-0.518590) | 0.271884 / 0.579283 (-0.307400) | 0.275270 / 0.434364 (-0.159094) | 0.303213 / 0.540337 (-0.237125) | 0.402338 / 1.386936 (-0.984598) |

</details>
</details>

![](https://cml.dev/watermark.png#bf8fa7ad7609ad34d4cc689f529ea606dd2560e0 "CML watermark")
I think this PR can be merged.you already have an approval, feel free to merge!
<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) | 0.004826 / 0.011353 (-0.006527) | 0.002979 / 0.011008 (-0.008029) | 0.062055 / 0.038508 (0.023547) | 0.056574 / 0.023109 (0.033465) | 0.244342 / 0.275898 (-0.031556) | 0.278040 / 0.323480 (-0.045439) | 0.004020 / 0.007986 (-0.003965) | 0.002474 / 0.004328 (-0.001855) | 0.048451 / 0.004250 (0.044200) | 0.038633 / 0.037052 (0.001580) | 0.251389 / 0.258489 (-0.007100) | 0.282739 / 0.293841 (-0.011102) | 0.023298 / 0.128546 (-0.105248) | 0.007513 / 0.075646 (-0.068134) | 0.203014 / 0.419271 (-0.216257) | 0.036216 / 0.043533 (-0.007317) | 0.250988 / 0.255139 (-0.004151) | 0.281228 / 0.283200 (-0.001972) | 0.018259 / 0.141683 (-0.123424) | 1.121200 / 1.452155 (-0.330955) | 1.184298 / 1.492716 (-0.308419) |

### 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) | 0.093730 / 0.018006 (0.075724) | 0.301716 / 0.000490 (0.301226) | 0.000223 / 0.000200 (0.000023) | 0.000051 / 0.000054 (-0.000004) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.019238 / 0.037411 (-0.018173) | 0.064329 / 0.014526 (0.049803) | 0.075657 / 0.176557 (-0.100899) | 0.122616 / 0.737135 (-0.614519) | 0.077459 / 0.296338 (-0.218880) |

### 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) | 0.280153 / 0.215209 (0.064944) | 2.715488 / 2.077655 (0.637833) | 1.449666 / 1.504120 (-0.054454) | 1.331903 / 1.541195 (-0.209292) | 1.396200 / 1.468490 (-0.072290) | 0.398861 / 4.584777 (-4.185916) | 2.402814 / 3.745712 (-1.342898) | 2.664033 / 5.269862 (-2.605829) | 1.619589 / 4.565676 (-2.946088) | 0.044798 / 0.424275 (-0.379477) | 0.004989 / 0.007607 (-0.002618) | 0.336822 / 0.226044 (0.110777) | 3.245604 / 2.268929 (0.976676) | 1.815633 / 55.444624 (-53.628991) | 1.557975 / 6.876477 (-5.318501) | 1.603655 / 2.142072 (-0.538417) | 0.462980 / 4.805227 (-4.342247) | 0.098340 / 6.500664 (-6.402324) | 0.042750 / 0.075469 (-0.032719) |

### 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) | 0.973785 / 1.841788 (-0.868003) | 12.379356 / 8.074308 (4.305048) | 10.540164 / 10.191392 (0.348772) | 0.144803 / 0.680424 (-0.535621) | 0.013875 / 0.534201 (-0.520326) | 0.270192 / 0.579283 (-0.309091) | 0.264614 / 0.434364 (-0.169750) | 0.313454 / 0.540337 (-0.226883) | 0.402310 / 1.386936 (-0.984626) |

</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) | 0.004987 / 0.011353 (-0.006366) | 0.003017 / 0.011008 (-0.007992) | 0.048592 / 0.038508 (0.010084) | 0.059370 / 0.023109 (0.036261) | 0.277536 / 0.275898 (0.001638) | 0.300592 / 0.323480 (-0.022888) | 0.004870 / 0.007986 (-0.003115) | 0.002452 / 0.004328 (-0.001876) | 0.047972 / 0.004250 (0.043721) | 0.042336 / 0.037052 (0.005283) | 0.277570 / 0.258489 (0.019081) | 0.304739 / 0.293841 (0.010898) | 0.025313 / 0.128546 (-0.103233) | 0.007219 / 0.075646 (-0.068427) | 0.053967 / 0.419271 (-0.365304) | 0.033314 / 0.043533 (-0.010219) | 0.273908 / 0.255139 (0.018769) | 0.291913 / 0.283200 (0.008713) | 0.019440 / 0.141683 (-0.122243) | 1.111047 / 1.452155 (-0.341107) | 1.191276 / 1.492716 (-0.301440) |

### 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) | 0.093985 / 0.018006 (0.075979) | 0.303105 / 0.000490 (0.302615) | 0.000235 / 0.000200 (0.000035) | 0.000043 / 0.000054 (-0.000011) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.022226 / 0.037411 (-0.015186) | 0.072151 / 0.014526 (0.057625) | 0.081700 / 0.176557 (-0.094857) | 0.121407 / 0.737135 (-0.615729) | 0.083217 / 0.296338 (-0.213121) |

### 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) | 0.297286 / 0.215209 (0.082077) | 2.913392 / 2.077655 (0.835738) | 1.591758 / 1.504120 (0.087638) | 1.463339 / 1.541195 (-0.077856) | 1.495095 / 1.468490 (0.026605) | 0.414341 / 4.584777 (-4.170436) | 2.412438 / 3.745712 (-1.333275) | 2.611452 / 5.269862 (-2.658410) | 1.658545 / 4.565676 (-2.907132) | 0.047269 / 0.424275 (-0.377007) | 0.004872 / 0.007607 (-0.002735) | 0.350746 / 0.226044 (0.124701) | 3.491482 / 2.268929 (1.222554) | 1.999009 / 55.444624 (-53.445616) | 1.672862 / 6.876477 (-5.203615) | 1.863095 / 2.142072 (-0.278977) | 0.484746 / 4.805227 (-4.320481) | 0.100774 / 6.500664 (-6.399890) | 0.042519 / 0.075469 (-0.032950) |

### 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) | 0.984497 / 1.841788 (-0.857291) | 12.972576 / 8.074308 (4.898268) | 10.886021 / 10.191392 (0.694629) | 0.141639 / 0.680424 (-0.538785) | 0.015726 / 0.534201 (-0.518475) | 0.284160 / 0.579283 (-0.295123) | 0.291437 / 0.434364 (-0.142927) | 0.314121 / 0.540337 (-0.226217) | 0.420439 / 1.386936 (-0.966497) |

</details>
</details>

![](https://cml.dev/watermark.png#87ad7c7767b9cda62113c207f0ff42506a8f27c0 "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) | 0.004881 / 0.011353 (-0.006472) | 0.002550 / 0.011008 (-0.008458) | 0.062171 / 0.038508 (0.023663) | 0.055341 / 0.023109 (0.032232) | 0.243132 / 0.275898 (-0.032766) | 0.265174 / 0.323480 (-0.058306) | 0.002934 / 0.007986 (-0.005052) | 0.002233 / 0.004328 (-0.002096) | 0.049302 / 0.004250 (0.045052) | 0.039491 / 0.037052 (0.002439) | 0.252776 / 0.258489 (-0.005713) | 0.280923 / 0.293841 (-0.012918) | 0.022585 / 0.128546 (-0.105962) | 0.006888 / 0.075646 (-0.068759) | 0.202751 / 0.419271 (-0.216521) | 0.035250 / 0.043533 (-0.008283) | 0.251745 / 0.255139 (-0.003394) | 0.267431 / 0.283200 (-0.015768) | 0.019486 / 0.141683 (-0.122197) | 1.161783 / 1.452155 (-0.290372) | 1.194254 / 1.492716 (-0.298463) |

### 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) | 0.097772 / 0.018006 (0.079766) | 0.309137 / 0.000490 (0.308647) | 0.000225 / 0.000200 (0.000025) | 0.000052 / 0.000054 (-0.000002) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.018719 / 0.037411 (-0.018693) | 0.062211 / 0.014526 (0.047686) | 0.074291 / 0.176557 (-0.102266) | 0.119436 / 0.737135 (-0.617699) | 0.075519 / 0.296338 (-0.220820) |

### 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) | 0.279778 / 0.215209 (0.064569) | 2.730678 / 2.077655 (0.653023) | 1.413922 / 1.504120 (-0.090198) | 1.286747 / 1.541195 (-0.254447) | 1.299835 / 1.468490 (-0.168656) | 0.392516 / 4.584777 (-4.192261) | 2.381816 / 3.745712 (-1.363896) | 2.616944 / 5.269862 (-2.652918) | 1.606152 / 4.565676 (-2.959525) | 0.044867 / 0.424275 (-0.379408) | 0.004915 / 0.007607 (-0.002692) | 0.334078 / 0.226044 (0.108034) | 3.388096 / 2.268929 (1.119167) | 1.756666 / 55.444624 (-53.687958) | 1.497211 / 6.876477 (-5.379266) | 1.496787 / 2.142072 (-0.645285) | 0.469145 / 4.805227 (-4.336082) | 0.097821 / 6.500664 (-6.402843) | 0.041850 / 0.075469 (-0.033619) |

### 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) | 0.956878 / 1.841788 (-0.884910) | 11.520184 / 8.074308 (3.445875) | 10.659216 / 10.191392 (0.467824) | 0.143687 / 0.680424 (-0.536737) | 0.014118 / 0.534201 (-0.520083) | 0.270990 / 0.579283 (-0.308293) | 0.270057 / 0.434364 (-0.164306) | 0.311109 / 0.540337 (-0.229229) | 0.407042 / 1.386936 (-0.979894) |

</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) | 0.004816 / 0.011353 (-0.006537) | 0.002898 / 0.011008 (-0.008110) | 0.048540 / 0.038508 (0.010032) | 0.055286 / 0.023109 (0.032176) | 0.279086 / 0.275898 (0.003187) | 0.298950 / 0.323480 (-0.024529) | 0.004090 / 0.007986 (-0.003896) | 0.002497 / 0.004328 (-0.001832) | 0.049160 / 0.004250 (0.044910) | 0.040612 / 0.037052 (0.003560) | 0.287832 / 0.258489 (0.029343) | 0.305617 / 0.293841 (0.011776) | 0.023936 / 0.128546 (-0.104610) | 0.007565 / 0.075646 (-0.068081) | 0.054037 / 0.419271 (-0.365235) | 0.032389 / 0.043533 (-0.011144) | 0.283031 / 0.255139 (0.027892) | 0.295411 / 0.283200 (0.012212) | 0.018466 / 0.141683 (-0.123217) | 1.134660 / 1.452155 (-0.317495) | 1.196212 / 1.492716 (-0.296504) |

### 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) | 0.099961 / 0.018006 (0.081955) | 0.310831 / 0.000490 (0.310342) | 0.000238 / 0.000200 (0.000038) | 0.000045 / 0.000054 (-0.000010) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.021566 / 0.037411 (-0.015845) | 0.070255 / 0.014526 (0.055729) | 0.081221 / 0.176557 (-0.095336) | 0.119404 / 0.737135 (-0.617732) | 0.083005 / 0.296338 (-0.213333) |

### 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) | 0.302788 / 0.215209 (0.087579) | 2.928876 / 2.077655 (0.851221) | 1.601221 / 1.504120 (0.097101) | 1.485147 / 1.541195 (-0.056047) | 1.508698 / 1.468490 (0.040207) | 0.402783 / 4.584777 (-4.181994) | 2.432151 / 3.745712 (-1.313561) | 2.476848 / 5.269862 (-2.793013) | 1.585487 / 4.565676 (-2.980189) | 0.045965 / 0.424275 (-0.378310) | 0.004818 / 0.007607 (-0.002789) | 0.354847 / 0.226044 (0.128803) | 3.500670 / 2.268929 (1.231742) | 1.951904 / 55.444624 (-53.492720) | 1.675152 / 6.876477 (-5.201325) | 1.795971 / 2.142072 (-0.346101) | 0.470625 / 4.805227 (-4.334602) | 0.126080 / 6.500664 (-6.374584) | 0.040506 / 0.075469 (-0.034963) |

### 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) | 0.985251 / 1.841788 (-0.856536) | 12.316710 / 8.074308 (4.242402) | 10.674437 / 10.191392 (0.483045) | 0.133622 / 0.680424 (-0.546802) | 0.016756 / 0.534201 (-0.517445) | 0.269318 / 0.579283 (-0.309965) | 0.282258 / 0.434364 (-0.152106) | 0.309941 / 0.540337 (-0.230396) | 0.403189 / 1.386936 (-0.983747) |

</details>
</details>

![](https://cml.dev/watermark.png#08ceb927025575c453228cab31291b74043dba1a "CML watermark")
I am merging this PR because we need it by `datasets-server`.<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) | 0.004935 / 0.011353 (-0.006418) | 0.002643 / 0.011008 (-0.008365) | 0.064449 / 0.038508 (0.025941) | 0.053110 / 0.023109 (0.030001) | 0.261576 / 0.275898 (-0.014322) | 0.270866 / 0.323480 (-0.052614) | 0.002895 / 0.007986 (-0.005091) | 0.002349 / 0.004328 (-0.001979) | 0.047620 / 0.004250 (0.043370) | 0.038699 / 0.037052 (0.001647) | 0.246663 / 0.258489 (-0.011826) | 0.282021 / 0.293841 (-0.011820) | 0.022807 / 0.128546 (-0.105739) | 0.007242 / 0.075646 (-0.068404) | 0.204236 / 0.419271 (-0.215035) | 0.035429 / 0.043533 (-0.008104) | 0.241684 / 0.255139 (-0.013455) | 0.262343 / 0.283200 (-0.020857) | 0.020036 / 0.141683 (-0.121647) | 1.112687 / 1.452155 (-0.339467) | 1.167086 / 1.492716 (-0.325630) |

### 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) | 0.107059 / 0.018006 (0.089053) | 0.301036 / 0.000490 (0.300546) | 0.000224 / 0.000200 (0.000024) | 0.000048 / 0.000054 (-0.000006) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.018464 / 0.037411 (-0.018947) | 0.063822 / 0.014526 (0.049296) | 0.073562 / 0.176557 (-0.102994) | 0.120136 / 0.737135 (-0.616999) | 0.074934 / 0.296338 (-0.221405) |

### 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) | 0.275474 / 0.215209 (0.060265) | 2.714239 / 2.077655 (0.636584) | 1.455535 / 1.504120 (-0.048585) | 1.336530 / 1.541195 (-0.204665) | 1.359607 / 1.468490 (-0.108883) | 0.396303 / 4.584777 (-4.188474) | 2.366076 / 3.745712 (-1.379636) | 2.600755 / 5.269862 (-2.669107) | 1.572382 / 4.565676 (-2.993294) | 0.045795 / 0.424275 (-0.378480) | 0.004932 / 0.007607 (-0.002675) | 0.332175 / 0.226044 (0.106130) | 3.257843 / 2.268929 (0.988915) | 1.799021 / 55.444624 (-53.645603) | 1.532813 / 6.876477 (-5.343663) | 1.552279 / 2.142072 (-0.589794) | 0.471369 / 4.805227 (-4.333858) | 0.098931 / 6.500664 (-6.401733) | 0.042735 / 0.075469 (-0.032734) |

### 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) | 0.960779 / 1.841788 (-0.881009) | 11.741631 / 8.074308 (3.667322) | 10.355721 / 10.191392 (0.164329) | 0.129025 / 0.680424 (-0.551399) | 0.013794 / 0.534201 (-0.520407) | 0.267268 / 0.579283 (-0.312015) | 0.265582 / 0.434364 (-0.168782) | 0.306242 / 0.540337 (-0.234095) | 0.400367 / 1.386936 (-0.986569) |

</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) | 0.004966 / 0.011353 (-0.006387) | 0.002846 / 0.011008 (-0.008163) | 0.049104 / 0.038508 (0.010596) | 0.055436 / 0.023109 (0.032327) | 0.273892 / 0.275898 (-0.002006) | 0.300207 / 0.323480 (-0.023273) | 0.004017 / 0.007986 (-0.003969) | 0.002465 / 0.004328 (-0.001863) | 0.048088 / 0.004250 (0.043837) | 0.040037 / 0.037052 (0.002984) | 0.279918 / 0.258489 (0.021429) | 0.305378 / 0.293841 (0.011537) | 0.024326 / 0.128546 (-0.104220) | 0.006992 / 0.075646 (-0.068654) | 0.053545 / 0.419271 (-0.365726) | 0.032312 / 0.043533 (-0.011221) | 0.272899 / 0.255139 (0.017760) | 0.289683 / 0.283200 (0.006483) | 0.019121 / 0.141683 (-0.122562) | 1.133296 / 1.452155 (-0.318858) | 1.220989 / 1.492716 (-0.271728) |

### 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) | 0.093193 / 0.018006 (0.075187) | 0.307658 / 0.000490 (0.307168) | 0.000224 / 0.000200 (0.000024) | 0.000045 / 0.000054 (-0.000010) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.022906 / 0.037411 (-0.014506) | 0.080931 / 0.014526 (0.066405) | 0.081442 / 0.176557 (-0.095115) | 0.121150 / 0.737135 (-0.615986) | 0.083387 / 0.296338 (-0.212952) |

### 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) | 0.294979 / 0.215209 (0.079770) | 2.900090 / 2.077655 (0.822435) | 1.610061 / 1.504120 (0.105941) | 1.455118 / 1.541195 (-0.086077) | 1.456599 / 1.468490 (-0.011891) | 0.397919 / 4.584777 (-4.186858) | 2.421010 / 3.745712 (-1.324702) | 2.486527 / 5.269862 (-2.783334) | 1.573854 / 4.565676 (-2.991822) | 0.046199 / 0.424275 (-0.378076) | 0.004888 / 0.007607 (-0.002719) | 0.342183 / 0.226044 (0.116139) | 3.392068 / 2.268929 (1.123140) | 1.963688 / 55.444624 (-53.480936) | 1.667611 / 6.876477 (-5.208866) | 1.833706 / 2.142072 (-0.308367) | 0.509421 / 4.805227 (-4.295806) | 0.099669 / 6.500664 (-6.400995) | 0.041004 / 0.075469 (-0.034465) |

### 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) | 0.956314 / 1.841788 (-0.885474) | 12.190194 / 8.074308 (4.115886) | 10.417839 / 10.191392 (0.226447) | 0.144139 / 0.680424 (-0.536285) | 0.015841 / 0.534201 (-0.518359) | 0.270436 / 0.579283 (-0.308847) | 0.273952 / 0.434364 (-0.160412) | 0.303018 / 0.540337 (-0.237319) | 0.410163 / 1.386936 (-0.976773) |

</details>
</details>

![](https://cml.dev/watermark.png#aa8558fc7fe1f9f7675c7c5d21a14d1a19598296 "CML watermark")