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Database Opt
The document discusses the N+1 query problem in database performance, where loading a set of objects results in additional queries to fetch associated data, overwhelming the limited number of database connections. It describes how N+1 queries can result in hundreds of queries for a typical page. The solution is to use eager loading to include associated data in the initial queries whenever possible, and to cache counts of objects to avoid unnecessary queries. Optimizing databases through these methods is essential for building scalable web applications.
Database Opt
- 1. Chris Lehneis Charlotte Tregelles Howto Deal with N + 1 Queries Database Performance
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- 3. Scalability Challenge ❖ Databaseonly has a limited amount of connections. ❖ Bottleneck occurs when requests exceed number of connections.
- 4. What are N+ 1 Queries? ! ! ❖ N + 1 problem: Loading many objects from the database, and for each object 1 or more queries are made.
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- 7. Queries ❖ N+1 queries= potentially 100s of queries ❖ Average page has 5-6 queries
- 8. Bullet ❖ Use eagerloading to remove N + 1 queries ❖ Remove eager loading when unnecessary ❖ When to use counter cache
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- 10. Summary ❖ Optimizing databasesperformance is essential for scalable web applications! ! ❖ Use eager loading, its awesome, but only when beneficial. ! ❖ Cache when counting objects
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