Periodic 30-second hangs with small STN_MAX_SESSIONS
If STN_MAX_SESSIONS is explicitly set to a small value (such as 10), there is likely to be a periodic hang for as long as 30 seconds, after each 10 to 20 commits.
The problem is related to the speed in which the completed tranlog AIO buffers are recycled and available for use for subsequent commits. The STN_MAX_SESSIONS setting controls how many tranlog AIO buffers are allocated, and with sufficient buffers this problem does not occur. The default setting for STN_MAX_SESSIONS, 40, is recommended and with this setting, the problem does not occur.
Workaround
Avoid setting STN_MAX_SESSIONS to a small value. Even if the license limit is lower than the default of 40 (such as with the community license), the shared page cache allocates tranlog AIO buffers based on the STN_MAX_SESSIONS settings.
Last updated: 1/27/20