pyspark-cdc

A Python library for Change Data Capture (CDC) workflows using PySpark. This project provides tools to capture, optimize, validate, and manage data changes efficiently in distributed environments.

Features

• Full and incremental data capture.
• Cron-based scheduling utilities for Delta optimizations.
• No extra dependencies.
• Use internal commitInfo.userMetadata to store watermark.

Installation

You can install the package using pip :

pip install pyspark-cdc

Usage

Let's assume that there is a table in a PostgreSQL database. Use this module to capture it as a managed delta table.

from pyspark_cdc import capture

... # necessary variables

df = (
    spark.read.format("jdbc")
    .options(
        url=f"{postgresql_jdbc_url}",
        dbtable=f"{postgresql_schema}.{postgresql_table}",
        user=f"{postgresql_user}",
        password=f"{postgresql_password}",
        driver="org.postgresql.Driver",                # Ensure JDBC Driver JAR is in Spark.
    )
    .load()
)
# quick start
(
    capture(df, spark)
    .table(f"{catalog}.{database}.{table_name}")       # managed table name
    .mode("incremental")
    .format("delta")
    .primary_keys(["ID"])                              # PK
    .watermark_column("UPDATED_AT")                    # Watermark column
    .enable_deletion_detect()                          # detect DELETE operations
    .start()
)
# With more
(
    capture(df, spark)
    .table(f"{catalog}.{database}.{table_name}")
    .mode("incremental")
    .format("delta")
    .primary_keys(["ID"])
    .watermark_column("UPDATED_AT")
    .partition_by(["COUNTRY", "GENDER"])               # partitioning
    .schedule_zorder("*/3", ["FIRST_NAME", "SURNAME"]) # run z-order every 3 days
    .schedule_vacuum("5,20")                           # run vacuum on 5th and 20th every month
    .schedule_compaction("10-25")                      # run compaction every day between 5th and 25th every month
    .enable_deletion_detect()                          # detect hard delete operations in source side
    .table_properties(                                 # extra delta table properties
        {
            "delta.deletedFileRetentionDuration": "interval 3 day",
            "delta.logRetentionDuration": "interval 3 day",
            "delta.appendOnly": "false",
            "delta.enableDeletionVectors": "true",
        }
    )
    .options(                                         # extra DataFrame writer options
        {
            "maxRecordsPerFile": 1000,
        }
    )
    .start()
)

See the samples/ directory and the tests/ folder for more usage examples and test cases.

Delta Optimize

Note: Schedulers use standard day-of-the-month crontab expressions:

• *: any value
• ,: value list separator
• -: range of values
• /: step values
• 1-31: allowed values

⚠️ If you run capture multiple times in a day, the optimize schedulers are triggered during each run. You can turn it off by using .scheduler_switch("OFF")

Typical Scenarios

The following table summarizes common use cases:

To capture DELETE operations, use enable_deletion_detect(), it will compare records at two sides based on the PK(s).

Library Version Matrix

The version of this module follows Databricks Runtime LTS

License

This project is licensed under the MIT License. See LICENSE for details.

Contact

For questions or support, open an issue on GitHub.