extract-data

name	extract-data
description	Extract data from database tables to CSV/Parquet files

Extract Data Skill

Extracts data from database tables into local files (CSV, Parquet). Supports full and incremental extraction, parallel processing, and schema/table filtering.

Usage

starlake extract-data [options]

Options

• --config <value>: Extract configuration name (required): references a file in metadata/extract/
• --outputDir <value>: Where to output data files (required)
• --limit <value>: Limit number of records extracted per table
• --numPartitions <value>: Parallelism level for partitioned table extraction
• --parallelism <value>: Parallelism level of the overall extraction process
• --ignoreExtractionFailure: Continue extraction even if individual tables fail
• --clean: Clean all files for a table before extracting it
• --incremental: Export only new data since last extraction (uses timestamp tracking)
• --ifExtractedBefore <value>: Only extract if last extraction was before this datetime
• --includeSchemas <value>: Comma-separated list of schemas/domains to include
• --excludeSchemas <value>: Comma-separated list of schemas/domains to exclude
• --includeTables <value>: Comma-separated list of tables to include
• --excludeTables <value>: Comma-separated list of tables to exclude
• --reportFormat <value>: Report output format: console, json, or html

Configuration Context

Extract Configuration

# metadata/extract/externals.sl.yml
version: 1
extract:
  connectionRef: "source_postgres"
  jdbcSchemas:
    - schema: "sales"
      tables:
        - name: "orders"
          fullExport: false
          partitionColumn: "id"
          numPartitions: 4
          timestamp: "updated_at"
          fetchSize: 1000
        - name: "customers"
          fullExport: true
        - name: "*"               # All remaining tables

Examples

Full Data Extraction

starlake extract-data --config externals --outputDir /tmp/output

Incremental Extraction

Extract only rows added/updated since last extraction:

starlake extract-data --config externals --outputDir /tmp/output --incremental

Extract with Record Limit

starlake extract-data --config externals --outputDir /tmp/output --limit 1000

Extract Specific Schemas

starlake extract-data --config externals --outputDir /tmp/output --includeSchemas sales,hr

Extract Excluding Specific Tables

starlake extract-data --config externals --outputDir /tmp/output --excludeTables audit_log,temp_data

Parallel Extraction with Fault Tolerance

starlake extract-data --config externals --outputDir /tmp/output --parallelism 8 --ignoreExtractionFailure

Clean Before Extraction

starlake extract-data --config externals --outputDir /tmp/output --clean

Related Skills

• extract - Extract both schema and data
• extract-schema - Extract schema metadata only
• load - Load extracted data into the warehouse