How to Efficiently Paginate Large JDBC Result Sets Without `rs.absolute()`?

Efficient JDBC Pagination without Absolute Row Positioning

Problem:

You need to implement efficient pagination for large result sets in JDBC without using rs.absolute() or rownum/limit offset.

Approach:

Although JDBC does not natively provide pagination support, you can implement it efficiently by modifying your SQL query directly.

Solution:

1. Use Database-Specific Pagination Keywords:

   Certain databases (e.g., MySQL, PostgreSQL) offer pagination-specific keywords like LIMIT and OFFSET. For example:

   SELECT * FROM data LIMIT 50 OFFSET 0;

2. Subquery with Row Number (Oracle):

   Oracle does not have a built-in pagination keyword. Instead, you can use a subquery with the ROWNUM pseudocolumn:

   SELECT *
   FROM (
       SELECT sub_data.*, rownum rnum
       FROM data sub_data
   )
   WHERE rnum BETWEEN 1 AND 50;

Advantages of Database Pagination:

• Efficient: Database-specific pagination keywords leverage database optimizations for efficient result retrieval.
• Portable: Subquery approach ensures portability across databases, although it might be less efficient in some cases.

Alternative Approaches:

• Cache ResultSet: Fetch the entire result set and cache it in memory. This approach is suitable for small result sets but may not be feasible for large datasets.
• Streaming: Use a streaming API to process results incrementally, reducing memory usage. However, this approach is not supported by all JDBC drivers.

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