Comments on: How to implement a queue in SQL

By: Xaprb

Xaprb — Tue, 29 Jun 2010 12:52:24 +0000

Glancing at it briefly, I think it’ll suffer under high traffic. But, I believe, so will my original post above — I wrote this at a time when I didn’t have that much experience with queues in MySQL. Since then I’ve seen that it is a hard problem that rarely scales well.

By: Thomas

Thomas — Mon, 28 Jun 2010 13:52:04 +0000

Interesting approaches, but most of them have the problem to lock the table on concurrent access. If one takes InnoDB as table type, the performance of MAX() falls by the wayside and using MyISAM would bring the aforementioned concurrency problem when reading and writing in parallel. I use a modified approach by Robert Eisele as a my queue logic, which outperforms the presented approaches: http://www.xarg.org/2009/09/fast-circular-buffer-in-mysql/

Thomas

By: Rdb Notes · How to implement a queue in SQL at Xaprb

Rdb Notes · How to implement a queue in SQL at Xaprb — Thu, 30 Aug 2007 15:03:28 +0000

[...] How to implement a queue in SQL at Xaprb This article explains how to create a fixed-size FIFO (first-in, first-out) queue in SQL, where rows added after a threshold will cause the oldest row to be deleted. There are several ways to do this, but MERGE on Oracle and DB2, and MySQLâ€™s non-standard extensions to SQL, make an elegant solution easy. [...]

By: Anish

Anish — Tue, 24 Jul 2007 06:23:26 +0000

Great article! How do I ensure unique value in fruit column, say no other rows should have ‘peaches’ if it is already in queue

By: Xaprb

Xaprb — Fri, 30 Mar 2007 13:19:45 +0000

It might work to use a calculation like TO_DAYS(CURRENT_DATE) % 60, or some variation thereof.