chdb DataStore - It's Just Faster Pandas
The Key Insight
# Change this:
import pandas as pd
# To this:
import chdb.datastore as pd
# Everything else stays the same.
DataStore is a lazy, ClickHouse-backed pandas replacement. Your existing pandas code works unchanged - but operations compile to optimized SQL and execute only when results are needed (e.g., print(), len(), iteration).
pip install chdb
Decision Tree: Pick the Right Approach
1. "I have a file/database and want to analyze it with pandas"
-> DataStore.from_file() / from_mysql() / from_s3() etc.
-> See references/connectors.md
2. "I need to join data from different sources"
-> Create DataStores from each source, use .join()
-> See examples/examples.md #3-5
3. "My pandas code is too slow"
-> import chdb.datastore as pd - change one line, keep the rest
4. "I need raw SQL queries"
-> Use the chdb-sql skill instead
Connect to Any Data Source - One Pattern
from datastore import DataStore
# Local file (auto-detects .parquet, .csv, .json, .arrow, .orc, .avro, .tsv, .xml)
ds = DataStore.from_file("sales.parquet")
# Database
ds = DataStore.from_mysql(host="db:3306", database="shop", table="orders", user="root", password="pass")
# Cloud storage
ds = DataStore.from_s3("s3://bucket/data.parquet", nosign=True)
# URI shorthand - auto-detects source type
ds = DataStore.uri("mysql://root:pass@db:3306/shop/orders")
All 16+ sources and URI schemes -> connectors.md
After Connecting - Full Pandas API
result = ds[ds["age"] > 25] # filter
result = ds[["name", "city"]] # select columns
result = ds.sort_values("revenue", ascending=False) # sort
result = ds.groupby("dept")["salary"].mean() # groupby
result = ds.assign(margin=lambda x: x["profit"] / x["revenue"]) # computed column
ds["name"].str.upper() # string accessor
ds["date"].dt.year # datetime accessor
result = ds1.join(ds2, on="id") # join
result = ds.head(10) # preview
print(ds.to_sql()) # see generated SQL
209 DataFrame methods supported. Full API -> api-reference.md
Cross-Source Join - The Killer Feature
from datastore import DataStore
customers = DataStore.from_mysql(host="db:3306", database="crm", table="customers", user="root", password="pass")
orders = DataStore.from_file("orders.parquet")
result = (orders
.join(customers, left_on="customer_id", right_on="id")
.groupby("country")
.agg({"amount": "sum", "rating": "mean"})
.sort_values("sum", ascending=False))
print(result)
More join examples -> examples.md
Writing Data
source = DataStore.from_mysql(host="db:3306", database="shop", table="orders", user="root", password="pass")
target = DataStore("file", path="summary.parquet", format="Parquet")
target.insert_into("category", "total", "count").select_from(
source.groupby("category").select("category", "sum(amount) AS total", "count() AS count")
).execute()
Troubleshooting
| Problem | Fix |
|---|
ImportError: No module named 'chdb' | pip install chdb |
ImportError: cannot import 'DataStore' | Use from datastore import DataStore or from chdb.datastore import DataStore |
| Database connection timeout | Include port in host: host="db:3306" not host="db" |
| Join returns empty result | Check key types match (both int or both string); use .to_sql() to inspect |
| Unexpected results | Call ds.to_sql() to see the generated SQL and debug |
| Environment check | Run python scripts/verify_install.py (from skill directory) |
References
Note: This skill teaches how to use chdb DataStore.
For raw SQL queries, use the chdb-sql skill.
For contributing to chdb source code, see CLAUDE.md in the project root.