How to Optimize Offset in Business Development?

This topic has been translated from a Chinese forum by GPT and might contain errors.

Original topic: 业务开发中,如何优化 offset?

| username: TiDBer_JUi6UvZm

Offset will scan the skipped data in front. Besides using Keyset Seeker, how else can offset be optimized in business development?

| username: TiDBer_JUi6UvZm | Original post link

Keyset Seeker achieves the effect of reducing record scans by creating an index on the fields used in the order by clause and then specifying specific values in the where condition to skip certain records. Is my understanding correct?

| username: Billmay表妹 | Original post link

In TiDB, the OFFSET clause typically causes the database to scan and skip the preceding data, which can impact query performance, especially when dealing with large amounts of data. Besides using the Keyset Seeker method, there are other ways to optimize OFFSET to reduce the effect of record scanning.

  1. Using LIMIT and OFFSET Together: When using OFFSET, try to combine it with LIMIT to restrict the number of rows returned. This can reduce the amount of data that needs to be scanned, improving query performance.

  2. Using Cursor Pagination: By recording the unique identifier (such as the primary key value) of the last record from the previous query result, you can use this identifier as a condition in the next query to avoid scanning the preceding data. This method is similar to Keyset Seeker but does not require creating additional indexes, instead utilizing existing unique identifier fields.

  3. Using Subqueries: Replace OFFSET with subqueries to skip the preceding data. This method may be more efficient than directly using OFFSET.

  4. Pagination Caching: In business development, consider using caching to store paginated data, reducing the number of database queries. When a user requests the next page of data, first check if the corresponding data exists in the cache, and if it does, return it directly, reducing the database query load.

Your understanding of Keyset Seeker is correct. Keyset Seeker optimizes OFFSET performance by creating an index on the ORDER BY field and specifying specific values in the WHERE condition to skip certain records, thereby reducing the effect of record scanning. This method can effectively optimize OFFSET performance, especially in cases of large data volumes.

| username: TiDBer_JUi6UvZm | Original post link

Got it!

| username: dba远航 | Original post link

The main method used is Keyset Seeker.

| username: system | Original post link

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