As of MySQL 5.6.2, the
configuration option allows you to configure the maximum size of
the change buffer as a percentage of the total size of the
buffer pool. By default,
is set to 25. The maximum setting is 50.
You might consider increasing
on a MySQL server with heavy insert, update, and delete
activity, where change buffer merging does not keep pace with
new change buffer entries, causing the change buffer to reach
its maximum size limit.
You might consider decreasing
on a MySQL server with static data used for reporting, or if the
change buffer consumes too much of the memory space that is
shared with the buffer pool, causing pages to age out of the
buffer pool sooner than desired.
Test different settings with a representative workload to
determine an optimal configuration. The
setting is dynamic, which allows you modify the setting without
restarting the server.