This document outlines the functionality and characteristics of the BigQuery Reader node, which enables automated data retrieval from Google BigQuery.

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Node Inputs

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Required Fields

  • Project: Your Google Cloud project ID
    • Example: my-gcp-project
  • Dataset: The dataset containing your target table
    • Example: my_dataset
  • Table: The specific table to query
    • Example: my_table
  • Query: Your SQL SELECT query
    • Example: SELECT * FROM my_dataset.my_table

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Optional Field

  • Maximum Bytes Billed: Limit to control query costs

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Node Output

Each selected column in your query becomes an output containing a list of values from that column.

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Node Functionality

The BigQuery Reader node executes SQL queries against Google BigQuery tables. Key features include:
  • Support for complex SQL queries
  • Cost control through byte billing limits
  • Batch processing capabilities
  • Dynamic output generation
  • Secure authentication with Gumloop

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When To Use

The BigQuery Reader node is particularly valuable in scenarios requiring data extraction from BigQuery. Common use cases include:
  • Data Analysis: Extract datasets for processing
  • Reporting: Generate regular business reports
  • Data Migration: Move data between systems
  • Monitoring: Track changes in data over time
Some specific examples:
  • Daily sales performance analysis
  • Customer behavior tracking
  • Inventory level monitoring
  • Transaction pattern analysis

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Example

To query recent sales data: 
SELECT 
  date,
  product_name,
  quantity,
  revenue
FROM my_dataset.sales
WHERE date >= DATE_SUB(CURRENT_DATE(), INTERVAL 7 DAY)

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Important Considerations:

  1. Requires Authentication with Google - Set up in the Credentials page
  2. Use column specifications instead of SELECT *
  3. Include WHERE clauses to limit data when possible
  4. May require reauthentication based on Google Admin policies

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Resolving Authentication Issues

If you experience frequent reauthentication requests:
  1. Set Gumloop as a Trusted App in Google Admin console
  2. Adjust reauthentication policies for Trusted Apps
  3. For detailed guidance, visit Google Admin Reauthentication Policy
In summary, the BigQuery Reader node provides powerful data extraction capabilities from Google BigQuery, with features for cost control and efficient data retrieval. For authentication support, reach out on the Gumloop Forum.