> ## Documentation Index
> Fetch the complete documentation index at: https://docs.popsink.com/llms.txt
> Use this file to discover all available pages before exploring further.

# BigQuery Source

The BigQuery Source Connector streams changes from Google BigQuery tables into Popsink pipelines using the native `CHANGES()` function. It performs an initial full load of each selected table, then polls for incremental changes (inserts, updates, and deletes) every 10 minutes, making your warehouse data available downstream without manual exports.

## Key Features

* **Native change history:** uses BigQuery's `CHANGES()` function — no extra infrastructure in your GCP project.
* **Initial Load:** the connector automatically performs an initial full table load, then switches to incremental polling.
* **Schema evolution:** the table schema is re-introspected on every poll cycle, and the stream schema is updated automatically when columns are added or removed.

## Prerequisites

1. A **GCP service account** with BigQuery read permissions on the target dataset (including `bigquery.tables.getData`).
2. **Change history** enabled on the tables you want to replicate:
   ```sql theme={null}
   ALTER TABLE <your_table> SET OPTIONS (enable_change_history = TRUE);
   ```
   BigQuery retains change history for up to 7 days by default.
3. Selected tables should be **standard tables** — views and external tables are not supported.

## Configuration

| Field               | Required | Description                                                                     |
| ------------------- | -------- | ------------------------------------------------------------------------------- |
| **Service Account** | Yes      | GCP service account key in JSON format — paste the full content of the key file |
| **Project**         | Yes      | GCP project ID where the BigQuery dataset lives (e.g. `my-gcp-project-123`)     |
| **Dataset**         | Yes      | BigQuery dataset containing the tables to replicate (e.g. `analytics`)          |

## Table Selection

After entering credentials, select tables from the discovered list. For each selected table the connector:

1. **Initial load:** reads all existing rows.
2. **CDC polling:** every 10 minutes, queries `CHANGES()` for inserts, updates, and deletes.

For details on change history retention and limitations, see the [BigQuery Change Data Capture documentation](https://cloud.google.com/bigquery/docs/change-data-capture).