Tag: SQL-Optimization

All the articles with the tag "SQL-Optimization".

• MySQL No-Offset Cursor Pagination — At 10M rows, OFFSET 1M takes 171ms / Cursor 0.30ms, and the 500x trap between them, traced down to a single line

  3 May, 2026

  On a 10M-row table, OFFSET 1M takes 171ms while a No-Offset cursor takes 0.30ms — about 570x faster, reproduced by direct measurement. But how you write the No-Offset code splits another 500x. The ANSI SQL row constructor `(a,b)<(?,?)` is logically equivalent to the OR-split form, yet the MySQL optimizer cannot push it down to an index range (154ms — about the same as OFFSET). The single line in EXPLAIN ANALYZE — Filter: vs Covering index range scan over — is the root cause. A production retrospective combined with a reproducible learning environment.