In the ETL (Extract, Transform, Load) process, the first phase is "Extraction." This phase is responsible for gathering data from various sources, such as databases, flat files, and cloud sources, and extracting it for further processing and storage in a data warehouse.

Tableau is a widely recognized BI tool known for its capability to handle large datasets and create interactive dashboards. It offers a user-friendly interface for data visualization, making it a preferred choice for data professionals and analysts.

The "Extraction" phase in the ETL (Extract, Transform, Load) process involves retrieving data from various source systems, which may be databases, files, or other data repositories. This phase is the initial step in data warehousing, where data is collected from its sources for further processing and analysis.

In an in-memory data warehouse, the primary method to ensure data durability and prevent data loss is through the use of persistent data snapshots. These snapshots capture the in-memory data and save it to durable storage, providing a backup that can be used to recover data in case of system failure or data corruption.

The dimension table in a data warehouse provides context to the facts. It contains descriptive attributes and hierarchies that are used for filtering and grouping data in queries. This helps analysts and users understand the data in the fact table and answer various business questions.

In a Snowflake Schema, the design intentionally allows for some level of data redundancy to optimize query performance. This schema structure involves normalized dimension tables, which can lead to better storage efficiency and reduced data update anomalies, even though it may have some level of redundancy.

Data Integration Tools are essential for combining data from various sources, such as databases, flat files, and cloud services, and loading it into the data warehouse. These tools handle data extraction, transformation, and loading (ETL) processes, ensuring data consistency and quality.

To support in-depth sales data analysis with dimensions like region, product, and time, the best choice would be a Star Schema in the data warehousing architecture. OLAP Cubes are used to efficiently process complex queries and aggregations. Star Schema's simplicity and denormalized structure are well-suited for such analytical tasks.

For a startup concerned about upfront infrastructure costs and scalability, a cloud-based data warehouse is a suitable choice. Cloud solutions offer flexibility, scalability, and a pay-as-you-go model, reducing the initial investment. They can easily scale resources up or down as business needs evolve.

In OLAP (Online Analytical Processing) cubes, a dimension is defined by the combination of measures (such as sales, revenue), attributes (such as product names, customer names), and hierarchies (such as time periods). Dimensions are essential for structuring and analyzing data within an OLAP cube, providing a multi-dimensional view of the data.