SQL on Nalar

Keyset Pagination for Stable and Efficient Database Queries

Tue, 01 Sep 2026 00:00:00 +0700

Pagination looks straightforward with LIMIT and OFFSET, but deep offsets become increasingly expensive and can produce unstable results when rows are inserted or deleted between requests.

Keyset pagination, also called seek pagination, uses the last seen sort key as the starting point for the next query.

Why OFFSET degrades

A typical query is:

$el.innerText = 'Copy', 2000)" class="absolute top-2 right-2 bg-neutral-700 text-white text-xs px-2 py-1 rounded opacity-0 group-hover:opacity-100 transition-opacity" > Copy

SELECT id, created_at, title
FROM posts
ORDER BY created_at DESC
LIMIT 50 OFFSET 100000;

The database still has to find and skip preceding rows before returning the page. There is also a correctness problem: if a new row is inserted at the front between requests, offsets shift and a user may see a duplicate or miss an item.

Keyset Pagination in SQL for Fast, Stable APIs

Tue, 01 Sep 2026 00:00:00 +0700

Pagination looks simple until a table becomes large or new rows are inserted while a client is paging through results. LIMIT and OFFSET are easy to understand, but deep offsets can become expensive and changing data can make rows appear twice or disappear between requests.

Keyset pagination, also called seek pagination, avoids those problems by asking for rows after a known position instead of asking the database to skip a number of rows.

Safe Database Migrations with the Expand-and-Contract Pattern

Tue, 01 Sep 2026 00:00:00 +0700

A schema migration can be syntactically correct and still cause an outage. Production deployments often run old and new application versions at the same time, background workers may lag behind, and a large table can turn a simple-looking DDL statement into a long lock.

The expand-and-contract pattern reduces those risks by splitting an incompatible change into compatible stages.

Why one-step schema changes are risky

Suppose an application wants to rename users.full_name to users.display_name.