Special:Search has a 'Remember selection for future searches' option in the advanced search profile. The search form itself is submitted via GET, so this means we are writing to the master database on GET requests. Not sure best option:
- Make all search requests POST's. In a multi-datacenter world this would force all search queries to the primary datacenter, even though we have search clusters in more than one DC that might be queried
- Do nothing, allowing cross-datacenter writes. Seems a poor solution, but usage of this feature is very low. The feature is used a good bit, but remembering a new configuration is relatively rare.
- Something else?