Enable Python logging

Use Python's logging module to see what the reader is doing. Logging is optional: failed reads still raise exceptions when it is disabled.

Show progress in a script

Configure logging before opening the table:

import logging
from delta_arrow_reader import DeltaTable

logging.basicConfig(level=logging.INFO)

table = DeltaTable("/path/to/table")
with table.to_reader(limit=10) as reader:
    result = reader.read_all()

Replace /path/to/table with your table's directory. This reads up to ten rows and prints INFO, WARNING, and ERROR messages to the terminal. For example, table_load.started means the reader began opening the table; scan_execution.completed means this read finished.

In a notebook or an application that already configures logging, basicConfig() may leave the existing settings unchanged. Set the reader's level in that configuration:

logging.getLogger("delta_arrow_reader").setLevel(logging.INFO)

The application's log output must also allow INFO messages. The reader uses the application's logging configuration.

Choose how much to log

Change the level to logging.DEBUG when investigating a problem. Level changes apply to later events, including reads from an existing table.

When a read fails

Handle the exception from opening, planning, or reading batches. Logging does not change whether the call succeeds. See Handle errors for the exceptions to catch and their error attributes.

Customize log records

If you need structured fields such as error codes in your log output, or want to write a custom handler, use Log records and handlers.