How to Optimize MySQL Queries with Large LIMIT Offsets?

Optimizing MySQL Queries with Large LIMIT Offsets

MySQL queries that utilize the LIMIT clause with large offsets can encounter significant performance issues. To address this challenge, consider the following optimization technique:

Indexing Table Approach

Rather than directly fetching rows using a LIMIT clause, create an indexing table that maps sequential keys to the primary key values in the target table. This allows you to efficiently retrieve data using an INNER JOIN and a WHERE clause.

Steps:

1. Create an indexing table:

   CREATE TABLE seq (
      seq_no int NOT NULL AUTO_INCREMENT,
      id int NOT NULL,
      PRIMARY KEY(seq_no),
      UNIQUE(id)
   );

2. Populate the indexing table:

   TRUNCATE seq;
   INSERT INTO seq (id) SELECT id FROM mytable ORDER BY id;

3. Retrieve data from the target table:

   SELECT mytable.*
   FROM mytable
   INNER JOIN seq USING(id)
   WHERE seq.seq_no BETWEEN 1000000 AND 1000999;

By utilizing this approach, you significantly enhance the performance of queries with large LIMIT offsets, enabling you to retrieve data efficiently.

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