Indexing slowness in Confluence with MySQL 5.5

Summary

Indexing takes significantly longer when running Confluence 5.9.4+ and MySQL 5.5 compared to Confluence 5.8

After addressing the previous ticket (CONF-39746) regarding this issue in Confluence 5.9.1 EAP version, it looks like the issue has re-occurred in newer versions of Confluence.

Environment

• MySQL 5.5
• Confluence 5.9.4

Steps to Reproduce

1. Compare amount of time taken to reindex Confluence 5.8.x and 5.9.4 running on MySQL 5.5

Expected Results

1. Indexing time is the same between both versions

Actual Results

For many of our customers, the amount of time it takes to reindex has increased many times. In one case, the amount of time to re-index went from 1 hour on Confluence 5.8.14, to 3 days in Confluence 5.9.4.

Notes

Many of our customers are currently running into this issue, which gets worse as their instance grows and the indexing queue gets backed up.

For some of our customers, there is no workaround as they are running Confluence on debian and cannot move to MySQL 5.6 via debian wheezy packages. Please see multiple comments added to this related bug with users still facing this issue on MySQL 5.5 for reference: CONF-40544

Workaround

If customers have the option, they can update MySQL to 5.6. For some of our customers (depending on their OS), there is no workaround.