[Python] Write_dataset() run time does not scale linearly with dataset size
- Dominant language
- C++
- Stars
- 17.1k
- Forks
- 4.3k
- Avg merge
- 3d 13h
- Merged PRs (30d)
- 88
Description
### Describe the bug, including details regarding any error messages, version, and platform.
I'd like to create a sample hive-partitioned dataset in parquet format.
Parameter "b" controls the amount of data.
b = 1010000 -> 10000 customer ids / 7440000 records -> Runs in 2 seconds
b = 1050000 -> 50000 customer ids / 37200000 records -> Runs in 8 minutes
b = 1100000 -> 100000 customer ids / 74400000 records -> Runs in 63 minutes
Shouldn't it scale linearly?
```
# Windows 11
#!pip install --upgrade polars==0.20.5
#!pip install --upgrade pyarrow==15.0.0
import polars as pl
import pyarrow.dataset as ds
from dateutil import rrule
from datetime import datetime
def ido():
return datetime.now().strftime('%Y.%m.%d. %H:%M:%S')
print(ido(),'started')
a = 1000000
b = 1010000 # Runs in 2 seconds
#b = 1050000 # Runs in 8 minutes
#b = 1100000 # Runs in 63 minutes
df1 = pl.DataFrame({'PARTY_ID': [i for i in range(a, b)]})
df2 = pl.DataFrame({'CALENDAR_DATE': [datetime.strftime(i,'%Y-%m-%d %H:%M:%S') for i in list(rrule.rrule(rrule.DAILY, count=186, dtstart=datetime(2023, 7, 21)))]})
df3 = pl.DataFrame({'CREDIT_FL': ['Y','N','Y', 'Y'],
'AMOUNT': [123, 789, 22, 44]})
df4 = (df1.join(df2,
how='cross'
)
.join(df3,
how='cross'
)
)
print(ido(),'data created')
print(ido(),df4.shape)
dft = df4.to_arrow()
print(ido(),'data converted to arrow')
ds.write_dataset(
dft,
'my_table',
format="parquet",
partitioning=["CALENDAR_DATE"],
partitioning_flavor="hive",
existing_data_behavior="delete_matching",
)
print(ido(),'finished')
```
### Component(s)
Python
Contributor guide
Assessment
This issue has not been assessed yet.