query-execution

Query Execution - Aggregations

Introduction Once the query planner has determined the optimal plan for executing a query, it's time to implement that plan. But before we can do that, it's important to understand the algorithms used to execute the various operations in the plan. In…

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hashing-schemes

Understanding hash indexes

Why database indexes? When it comes to querying databases, one of the most time-consuming and performance-intensive operations is to do a linear scan of the entire table. This requires the database management system (DBMS) to retrieve all of the page…

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