When a page is modified, the full text of the page is saved to the pageHistory table in the content column.
This can eat up both storage and memory quite fast for large pages with many changes, especially in multi-user wikis.
I would suggest storing only the changeset (i.e., the differences only, probably as a BLOB) instead of the full text.
For Git-backed wikis, I would suggest using Git for page histories instead of this internal system.
I would also suggest an option to disable page histories altogether, as well as an option to permanently clear the pageHistory table.