| XF 2.3 Add-ons (Free) Optimized List Queries by Xon 2.13.0

This add-on is aimed at large forum with tens of thousands to hundreds of thousands or more threads in a single forum. Smaller forum do not gain much benefit from this add-on.

Member List/Forum/Conversation/Reactions/XFMG lists:

MySQL/MariaDB implements 'early row lookup', when combined with LIMIT & OFFSET with a large offset, results in the large select statement pulling in more data than is required. Maybe one day MySQL/MariaDB will fix this. Maybe.

This causes an issue as this how conversations and threads implement paging.

This addon provides some optimized query for getting threads in a forum with large number of threads, or for conversations with a very high page count.

Ideally conversations would implement the position system like posts do, which would be even faster than using sub-selects to force 'late row lookup'.

For more information see:

• http://stackoverflow.com/questions/4481388/why-does-mysql-higher-limit-offset-slow-the-query-down
• http://explainextended.com/2009/10/23/mysql-order-by-limit-performance-late-row-lookups/

Configuration
Under "Performance":