DataStore uses Python’s standard logging module. This guide shows how to configure logging for debugging.
Quick Start
from pathlib import Path
Path("data.csv").write_text("""\
name,age,city,salary,department
Alice,25,NYC,55000,Engineering
Bob,30,LA,65000,Product
Charlie,35,NYC,80000,Engineering
Diana,28,SF,70000,Design
Eve,42,NYC,95000,Product
""")
from chdb import datastore as pd
from chdb.datastore.config import config
# Enable debug logging
config.enable_debug()
# Now all operations will log details
ds = pd.read_csv("data.csv")
result = ds.filter(ds['age'] > 25).to_df()Log Levels
| Level | Value | Description |
|---|---|---|
DEBUG |
10 | Detailed information for debugging |
INFO |
20 | General operational information |
WARNING |
30 | Warning messages (default) |
ERROR |
40 | Error messages |
CRITICAL |
50 | Critical failures |
Setting Log Level
import logging
from chdb.datastore.config import config
# Using standard logging levels
config.set_log_level(logging.DEBUG)
config.set_log_level(logging.INFO)
config.set_log_level(logging.WARNING) # Default
config.set_log_level(logging.ERROR)
# Using quick preset
config.enable_debug() # Sets DEBUG level + verbose formatLog Format
Simple Format (Default)
config.set_log_format("simple")DEBUG - Executing SQL query
DEBUG - Cache miss for key abc123Verbose Format
config.set_log_format("verbose")2024-01-15 10:30:45.123 DEBUG datastore.core - Executing SQL query
2024-01-15 10:30:45.456 DEBUG datastore.cache - Cache miss for key abc123What Gets Logged
DEBUG Level
- SQL queries generated
- Execution engine selection
- Cache operations (hits/misses)
- Operation timings
- Data source information
DEBUG - Creating DataStore from file 'data.csv'
DEBUG - SQL: SELECT * FROM file('data.csv', 'CSVWithNames') WHERE age > 25
DEBUG - Using engine: chdb
DEBUG - Execution time: 0.089s
DEBUG - Cache: Storing result (key: abc123)INFO Level
- Major operation completions
- Configuration changes
- Data source connections
INFO - Loaded 1,000,000 rows from data.csv
INFO - Execution engine set to: chdb
INFO - Connected to MySQL: localhost:3306/mydbWARNING Level
- Deprecated feature usage
- Performance warnings
- Non-critical issues
WARNING - Large result set (>1M rows) may cause memory issues
WARNING - Cache TTL exceeded, re-executing query
WARNING - Column 'date' has mixed types, using stringERROR Level
- Query execution failures
- Connection errors
- Data conversion errors
ERROR - Failed to execute SQL: syntax error near 'FORM'
ERROR - Connection to MySQL failed: timeout
ERROR - Cannot convert column 'price' to floatCustom Logging Configuration
Using Python Logging
import logging
# Configure root logger
logging.basicConfig(
level=logging.DEBUG,
format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
handlers=[
logging.FileHandler('datastore.log'),
logging.StreamHandler()
]
)
# Get DataStore logger
ds_logger = logging.getLogger('chdb.datastore')
ds_logger.setLevel(logging.DEBUG)Log to File
import logging
# Create file handler
file_handler = logging.FileHandler('datastore_debug.log')
file_handler.setLevel(logging.DEBUG)
file_handler.setFormatter(logging.Formatter(
'%(asctime)s - %(name)s - %(levelname)s - %(message)s'
))
# Add to DataStore logger
ds_logger = logging.getLogger('chdb.datastore')
ds_logger.addHandler(file_handler)Suppress Logging
import logging
# Suppress all DataStore logs
logging.getLogger('chdb.datastore').setLevel(logging.CRITICAL)
# Or using config
config.set_log_level(logging.CRITICAL)Debugging Scenarios
Debug SQL Generation
config.enable_debug()
ds = pd.read_csv("data.csv")
result = ds.filter(ds['age'] > 25).groupby('city').sum()Log output:
DEBUG - Creating DataStore from file 'data.csv'
DEBUG - Building filter: age > 25
DEBUG - Building groupby: city
DEBUG - Building aggregation: sum
DEBUG - Generated SQL:
SELECT city, SUM(*)
FROM file('data.csv', 'CSVWithNames')
WHERE age > 25
GROUP BY cityDebug Engine Selection
config.enable_debug()
result = ds.filter(ds['x'] > 10).apply(custom_func)Log output:
DEBUG - filter: selecting engine (eligible: chdb, pandas)
DEBUG - filter: using chdb (SQL-compatible)
DEBUG - apply: selecting engine (eligible: pandas)
DEBUG - apply: using pandas (custom function)Debug Cache Operations
config.enable_debug()
# First execution
result1 = ds.filter(ds['age'] > 25).to_df()
# DEBUG - Cache miss for query hash abc123
# DEBUG - Executing query...
# DEBUG - Caching result (key: abc123, size: 1.2MB)
# Second execution (same query)
result2 = ds.filter(ds['age'] > 25).to_df()
# DEBUG - Cache hit for query hash abc123
# DEBUG - Returning cached resultDebug Performance Issues
config.enable_debug()
config.enable_profiling()
# Logs will show timing for each operation
result = (ds
.filter(ds['amount'] > 100)
.groupby('region')
.agg({'amount': 'sum'})
.to_df()
)Log output:
DEBUG - filter: 0.002ms
DEBUG - groupby: 0.001ms
DEBUG - agg: 0.003ms
DEBUG - SQL generation: 0.012ms
DEBUG - SQL execution: 89.456ms <- Main time spent here
DEBUG - Result conversion: 2.345msProduction Configuration
Recommended Settings
import logging
from chdb.datastore.config import config
# Production: minimal logging
config.set_log_level(logging.WARNING)
config.set_log_format("simple")
config.set_profiling_enabled(False)Log Rotation
import logging
from logging.handlers import RotatingFileHandler
# Create rotating file handler
handler = RotatingFileHandler(
'datastore.log',
maxBytes=10*1024*1024, # 10MB
backupCount=5
)
handler.setLevel(logging.WARNING)
# Add to DataStore logger
logging.getLogger('chdb.datastore').addHandler(handler)Environment Variables
You can also configure logging via environment variables:
# Set log level
export CHDB_LOG_LEVEL=DEBUG
# Set log format
export CHDB_LOG_FORMAT=verboseimport os
import logging
# Read from environment
log_level = os.environ.get('CHDB_LOG_LEVEL', 'WARNING')
config.set_log_level(getattr(logging, log_level))Summary
| Task | Command |
|---|---|
| Enable debug | config.enable_debug() |
| Set level | config.set_log_level(logging.DEBUG) |
| Set format | config.set_log_format("verbose") |
| Log to file | Use Python logging handlers |
| Suppress logs | config.set_log_level(logging.CRITICAL) |