Pagination while sorting a non unique text column

Question

What are the ways to paginate a table on a non unique text column?

On a unique timestamp column, one can create an index on it and execute the following to move forward

SELECT * FROM users WHERE created > '<last element created timestamp>' ORDER BY created ASC LIMIT 20;

If it is a numerical primary key

SELECT * FROM users WHERE id > 100 ORDER BY id ASC LIMIT 20;

But what can one do when the table is ordered by non unique text column (first_name for example)?

First thing that comes to mind is the OFFSET method, but there are performance penalties on large tables.

Alternatively, one could use a cursor, but the internet agrees that it not recommended way on a public web application.

Answer 1

One solution that performs well would be being smart with indexes.

First, create an index on two columns, one being your non unique text column and a second one being your id column (it can be any column that can be differentiated between non unique text column rows):

CREATE INDEX user_name_uuid_idx
    ON public.user USING btree
    (name COLLATE pg_catalog."default" ASC NULLS LAST, uuid ASC NULLS LAST)
    TABLESPACE pg_default;

NOTE: the order of columns does matter. Use the same order that is used in the select query

Then use this query to get x page.

SELECT * FROM user WHERE (name, uuid) > ('Misty Wyman', '070d905d-2155-492f-b811-2c9d30015299') ORDER BY name, uuid LIMIT 20;