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Data Analysis and Performance Optimization Flashcards
Microsoft Power BI Data Analyst Flashcards
| Front | Back |
| How can customizing visuals improve performance? | Using tailored visuals reduces rendering complexity and minimizes resource consumption. |
| How can nested DAX measures affect performance? | They can create complex calculations, increasing query time and impacting overall efficiency. |
| How can you improve Power BI report performance? | Use aggregations, optimize DAX formulas, limit visuals per page, and disable unnecessary animations. |
| How can you reduce model size in Power BI? | Optimize column data types, remove unnecessary columns/tables, and use summarizations instead of detailed data. |
| How do measures differ from calculated columns? | Measures are calculations performed on aggregated data, while calculated columns create static values for each row. |
| How do you manage a slow Power BI dashboard? | Analyze query performance, simplify visuals, optimize DAX, and review data model efficiency. |
| How do you reduce filter complexity in Power BI? | Use slicers, well-defined relationships, and fewer calculated filters for faster performance. |
| How does caching improve Power BI performance? | Caching stores query results, reducing the need to fetch the same data repeatedly. |
| How does data modeling affect Power BI performance? | A well-structured data model reduces complexity, improves query performance, and enhances usability. |
| What are calculated columns in Power BI? | Calculated columns add new data to a table based on DAX expressions and row context. |
| What are common causes of high memory usage in Power BI? | Large datasets, complex relationships, high-cardinality columns, and inefficient DAX calculations. |
| What are Power BI aggregations useful for? | Aggregations pre-calculate data at higher levels, reducing query complexity and improving speed. |
| What are the benefits of disabling auto-refresh for visuals? | It prevents unnecessary data queries, improving dashboard loading times. |
| What does parallel loading of visuals in Power BI do? | It speeds up report rendering by loading multiple visuals simultaneously. |
| What is "DirectQuery" mode in Power BI? | DirectQuery keeps data in the source and queries it live, reducing storage but potentially increasing query latency. |
| What is "Import" mode in Power BI? | Import mode loads data into Power BI, enabling faster performance but requiring more memory/storage. |
| What is a "data lake" for Power BI? | A centralized repository for storing structured and unstructured data used for analysis. |
| What is a high-cardinality column? | A column with many unique values, which can increase processing time and memory usage. |
| What is DAX in Power BI? | DAX stands for Data Analysis Expressions and is a formula language used to create custom calculations and aggregations in Power BI. |
| What is table partitioning in Power BI? | Partitioning divides large tables into smaller subsets for optimized querying and processing. |
| What is the difference between a dataflow and a dataset? | A dataflow transforms and prepares data, while a dataset focuses on data ready for reporting. |
| What is the primary purpose of a Power BI gateway? | A gateway is used to access and refresh data sources that reside on-premises. |
| What is the purpose of relationship direction in Power BI? | It determines how filters flow between tables for accurate data analysis. |
| What is the role of column indexing in Power BI? | Indexing speeds up searches and queries by providing a faster path to data retrieval. |
| What Power BI feature allows column-based compression? | Power BI uses VertiPaq, a columnar storage engine for high data compression. |
| What tool checks Power BI report performance? | The Performance Analyzer tracks query duration and visual processing time. |
| Why should you avoid iterators like SUMX for large datasets? | Iterators loop row by row, which can significantly slow down performance for large datasets. |
Front
What is the primary purpose of a Power BI gateway?
Click the card to flip
Back
A gateway is used to access and refresh data sources that reside on-premises.
Front
What is the difference between a dataflow and a dataset?
Back
A dataflow transforms and prepares data, while a dataset focuses on data ready for reporting.
Front
What are calculated columns in Power BI?
Back
Calculated columns add new data to a table based on DAX expressions and row context.
Front
How does caching improve Power BI performance?
Back
Caching stores query results, reducing the need to fetch the same data repeatedly.
Front
What is DAX in Power BI?
Back
DAX stands for Data Analysis Expressions and is a formula language used to create custom calculations and aggregations in Power BI.
Front
What are Power BI aggregations useful for?
Back
Aggregations pre-calculate data at higher levels, reducing query complexity and improving speed.
Front
What is a "data lake" for Power BI?
Back
A centralized repository for storing structured and unstructured data used for analysis.
Front
What is the purpose of relationship direction in Power BI?
Back
It determines how filters flow between tables for accurate data analysis.
Front
What are common causes of high memory usage in Power BI?
Back
Large datasets, complex relationships, high-cardinality columns, and inefficient DAX calculations.
Front
What is table partitioning in Power BI?
Back
Partitioning divides large tables into smaller subsets for optimized querying and processing.
Front
How do measures differ from calculated columns?
Back
Measures are calculations performed on aggregated data, while calculated columns create static values for each row.
Front
What tool checks Power BI report performance?
Back
The Performance Analyzer tracks query duration and visual processing time.
Front
What are the benefits of disabling auto-refresh for visuals?
Back
It prevents unnecessary data queries, improving dashboard loading times.
Front
What is a high-cardinality column?
Back
A column with many unique values, which can increase processing time and memory usage.
Front
What is "DirectQuery" mode in Power BI?
Back
DirectQuery keeps data in the source and queries it live, reducing storage but potentially increasing query latency.
Front
How do you manage a slow Power BI dashboard?
Back
Analyze query performance, simplify visuals, optimize DAX, and review data model efficiency.
Front
How does data modeling affect Power BI performance?
Back
A well-structured data model reduces complexity, improves query performance, and enhances usability.
Front
How can you reduce model size in Power BI?
Back
Optimize column data types, remove unnecessary columns/tables, and use summarizations instead of detailed data.
Front
How can customizing visuals improve performance?
Back
Using tailored visuals reduces rendering complexity and minimizes resource consumption.
Front
How can you improve Power BI report performance?
Back
Use aggregations, optimize DAX formulas, limit visuals per page, and disable unnecessary animations.
Front
What is "Import" mode in Power BI?
Back
Import mode loads data into Power BI, enabling faster performance but requiring more memory/storage.
Front
How can nested DAX measures affect performance?
Back
They can create complex calculations, increasing query time and impacting overall efficiency.
Front
What does parallel loading of visuals in Power BI do?
Back
It speeds up report rendering by loading multiple visuals simultaneously.
Front
What Power BI feature allows column-based compression?
Back
Power BI uses VertiPaq, a columnar storage engine for high data compression.
Front
What is the role of column indexing in Power BI?
Back
Indexing speeds up searches and queries by providing a faster path to data retrieval.
Front
How do you reduce filter complexity in Power BI?
Back
Use slicers, well-defined relationships, and fewer calculated filters for faster performance.
Front
Why should you avoid iterators like SUMX for large datasets?
Back
Iterators loop row by row, which can significantly slow down performance for large datasets.
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This deck explores advanced analysis techniques, performance optimization strategies, and troubleshooting common issues in Power BI.