As of FogBugz 7.2.12, licensed FogBugz customers can do this:
Adding a string value named 'pctIndexThrottle' to the FogBugz registry settings (next to sConnectionString, for example) will allow throttling of the search indexer. Values are interpreted as percentages, so '50' would throttle the indexer to half, '200' would double it, '0' would disable it, '100' is the default, etc.
If you're having
The intended purpose of this problem in an On Demand environment... you shouldn't bethrottle is to temporarily reduce indexing load for servers which are having trouble indexing a set of particularly painful cases. Please contact Fog Creek supportSetting pctIndexThrottle to values above 1000, while permitted, is not advised.