The paper discusses various techniques to improve the efficiency of data processing in modern databases, particularly column-store databases. These techniques include:1. Data compression: Using dictionary-based compression or run-length encoding to reduce the amount of data processed.2. Vectorization: Representing data as vectors to improve performance for complex queries.3. Parallelization: Splitting large datasets into smaller chunks and processing them simultaneously to improve performance.4. Optimization of query plans: Using cost-based optimization and query rewriting to reduce the amount of data processed.5. Use of specialized hardware: Offloading computationally intensive tasks to GPUs or FPGAs.6. Data partitioning: Reducing the amount of data processed by partitioning or sampling the data.7. Query optimization: Improving query performance through techniques such as caching and query rewriting.8. Data pruning: Removing unnecessary data to improve performance.9. Index selection: Selecting appropriate indexes to improve query performance.10. Data layout optimization: Optimizing the layout of data to reduce the amount of data processed.The paper also identifies several open challenges and research directions, including:1. Improving data compression techniques.2. Developing better query optimization techniques for complex queries.3. Investigating the use of specialized hardware for database performance enhancement.4. Exploring new data partitioning and sampling techniques.5. Developing better algorithms for data layout optimization and sampling.6. Improving the efficiency of data rewriting techniques.7. Investigating the use of machine learning and artificial intelligence techniques to improve database performance.8. Exploring new distributed computing architectures to support large-scale databases.9. Developing better query optimization and caching techniques for complex queries.10. Improving the efficiency of data pruning and subset rewriting techniques.