> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-mintlify-8c05c8a2.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Journalisation de DataStore

> Configurer la journalisation de DataStore pour le débogage et la supervision

DataStore utilise le module de journalisation standard de Python. Ce guide explique comment configurer la journalisation à des fins de débogage.

<div id="quick-start">
  ## Démarrage rapide
</div>

```python theme={null}
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()
```

<div id="levels">
  ## Niveaux de journalisation
</div>

| Niveau     | Valeur | Description                              |
| ---------- | ------ | ---------------------------------------- |
| `DEBUG`    | 10     | Informations détaillées pour le débogage |
| `INFO`     | 20     | Informations générales de fonctionnement |
| `WARNING`  | 30     | Messages d’avertissement (par défaut)    |
| `ERROR`    | 40     | Messages d’erreur                        |
| `CRITICAL` | 50     | Défaillances critiques                   |

<div id="setting-level">
  ## Définir le niveau de journalisation
</div>

```python theme={null}
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 format
```

<div id="format">
  ## Format des logs
</div>

<div id="simple">
  ### Format simple (par défaut)
</div>

```python title="Query" theme={null}
config.set_log_format("simple")
```

```text title="Response" theme={null}
DEBUG - Executing SQL query
DEBUG - Cache miss for key abc123
```

<div id="verbose">
  ### Format verbose
</div>

```python title="Query" theme={null}
config.set_log_format("verbose")
```

```text title="Response" theme={null}
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 abc123
```

***

<div id="what-logged">
  ## Ce qui est consigné
</div>

<div id="debug-logged">
  ### Niveau DEBUG
</div>

* Requêtes SQL générées
* Sélection du moteur d’exécution
* Opérations du cache (hits/misses)
* Durée des opérations
* Informations sur la source de données

```text theme={null}
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)
```

<div id="info-logged">
  ### Niveau INFO
</div>

* Achèvement des opérations majeures
* Modifications de la configuration
* Connexions aux sources de données

```text theme={null}
INFO - Loaded 1,000,000 rows from data.csv
INFO - Execution engine set to: chdb
INFO - Connected to MySQL: localhost:3306/mydb
```

<div id="warning-logged">
  ### Niveau WARNING
</div>

* Utilisation de fonctionnalités obsolètes
* Avertissements de performance
* Problèmes non critiques

```text theme={null}
WARNING - Large result set (>1M rows) may cause memory issues
WARNING - Cache TTL exceeded, re-executing query
WARNING - Column 'date' has mixed types, using string
```

<div id="error-logged">
  ### Niveau ERROR
</div>

* Erreurs lors de l’exécution des requêtes
* Erreurs de connexion
* Erreurs de conversion des données

```text theme={null}
ERROR - Failed to execute SQL: syntax error near 'FORM'
ERROR - Connection to MySQL failed: timeout
ERROR - Cannot convert column 'price' to float
```

***

<div id="custom">
  ## Configuration personnalisée de la journalisation
</div>

<div id="python-logging">
  ### Utiliser le module de journalisation de Python
</div>

```python theme={null}
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)
```

<div id="log-file">
  ### Journalisation dans un fichier
</div>

```python theme={null}
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)
```

<div id="suppress">
  ### Désactiver la journalisation
</div>

```python theme={null}
import logging

# Suppress all DataStore logs
logging.getLogger('chdb.datastore').setLevel(logging.CRITICAL)

# Or using config
config.set_log_level(logging.CRITICAL)
```

***

<div id="scenarios">
  ## Scénarios de débogage
</div>

<div id="debug-sql">
  ### Débogage de la génération SQL
</div>

```python theme={null}
config.enable_debug()

ds = pd.read_csv("data.csv")
result = ds.filter(ds['age'] > 25).groupby('city').sum()
```

Sortie des logs :

```text theme={null}
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 city
```

<div id="debug-engine">
  ### Débogage de la sélection du moteur
</div>

```python theme={null}
config.enable_debug()

result = ds.filter(ds['x'] > 10).apply(custom_func)
```

Sortie des logs :

```text theme={null}
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)
```

<div id="debug-cache">
  ### Débogage des opérations du cache
</div>

```python theme={null}
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 result
```

<div id="debug-performance">
  ### Débogage des problèmes de performances
</div>

```python theme={null}
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()
)
```

Sortie des logs :

```text theme={null}
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: 2.345ms
```

***

<div id="production">
  ## Configuration de production
</div>

<div id="recommended">
  ### Paramètres recommandés
</div>

```python theme={null}
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)
```

<div id="rotation">
  ### Rotation des logs
</div>

```python theme={null}
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)
```

***

<div id="env-vars">
  ## Variables d’environnement
</div>

Vous pouvez également configurer la journalisation à l’aide de variables d’environnement :

```bash theme={null}
# Set log level
export CHDB_LOG_LEVEL=DEBUG

# Set log format
export CHDB_LOG_FORMAT=verbose
```

```python theme={null}
import os
import logging

# Read from environment
log_level = os.environ.get('CHDB_LOG_LEVEL', 'WARNING')
config.set_log_level(getattr(logging, log_level))
```

***

<div id="summary">
  ## Résumé
</div>

| Tâche                  | Commande                                               |
| ---------------------- | ------------------------------------------------------ |
| Activer le débogage    | `config.enable_debug()`                                |
| Définir le niveau      | `config.set_log_level(logging.DEBUG)`                  |
| Définir le format      | `config.set_log_format("verbose")`                     |
| Écrire dans un fichier | Utiliser les gestionnaires du module logging de Python |
| Désactiver les logs    | `config.set_log_level(logging.CRITICAL)`               |