https://andreas.scherbaum.la/tags/random/Recent content in Random on ads' cornerHugoen-usSun, 04 Feb 2007 21:50:30 +0100https://andreas.scherbaum.la/post/2007-02-04_ringbuffer-in-sql/Sun, 04 Feb 2007 21:50:30 +0100https://andreas.scherbaum.la/post/2007-02-04_ringbuffer-in-sql/<p>On a student platform we show, on every page, a random user in the upper right corner. Because we have over 11.000 users, the database has to select all matching users and sort them by <code>random()</code>. Thats very expensive and one of the longest running queries in the current version. And because we are currently redeveloping the whole platform, I decided to try something different for the random user. The user must not be really random, it should be enough to just display a different user every time the page is displayed. My idea was to implement a ringbuffer in SQL and forward the pointer to the next user in the buffer if we need to search the next random user.</p>