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86. How To Stream Result Set Via Spring Data In MySQL

Note: For web-applications, pagination should be the way to go, not streaming. But, if you choose streaming then keep in mind the golden rule: keep th result set as small as posible. Also, keep in mind that the Execution Plan might not be as efficient as when using SQL-level pagination.

Description: This application is an example of streaming the result set via Spring Data and MySQL. This example can be adopted for databases that fetches the entire result set in a single roundtrip causing performance penalties.

Key points:

• rely on forward-only result set (default in Spring Data)
• rely on read-only statement (add @Transactional(readOnly=true))
• set the fetch-size set (e.g. 30, or row-by-row; Integer.MIN_VALUE (recommended in MySQL))
• for MySQL, set Statement fetch-size to Integer.MIN_VALUE, or add useCursorFetch=true to the JDBC URL and set Statement fetch-size to a positive integer (e.g., 30)

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