Big data & Spark
PySpark jobs, partitioning, batch processing, and large-dataset transform patterns.
Bloom Filter Join Mock in Python
A mock hash join that uses a Bloom filter to pre-filter one table before performing an exact match, reducing the number of comparisons in large dataset joins.
import hashlib
import random
import string
class BloomFilter:
def __init__(self, size: int = 200, num_hashes: int = 3):
self.bits = [False] * size
self.size = size
self.num_hashes = num_hashes
def _hashes(self, item: str):
result = []
for seed in range(self.num_hashes…
How to Mock a Hash Join on Large and Small Tables in Python
This code efficiently joins a large dataset (1000 rows) with a small lookup table (20 rows) by building a dictionary hash lookup, mimicking a hash join strategy used in big data systems.
import random
from pprint import pprint
# Large table: 1000 rows (id, group_id, value)
large = [{"id": i, "group_id": random.randint(1, 20), "value": random.random() * 100} for i in range(1000)]
# Small table: 20 rows (group_id, label)
small = [{"group_id": g, "label": f"Group-{g}"} for g in range(1, 21)]
# Mock a …
Skew Join Salting Key in Python (Demo)
Demonstrates skew join salting by expanding a smaller side with salt keys and matching rows on the larger side via random salt assignment.
import random
def skew_join_salting_key(left_df, right_df, salt_range=4):
"""
Demonstrates skew join salting: expand the smaller side with salt keys,
then attach a salt key to each row on the larger side.
Returns a list of (left, right, salt) tuples.
"""
skewed_left = []
for row in left_d…
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Big data & Spark — Python code examples
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