Performance of the copying part of the sphinx indexer

[pauamma]

Currently, the sphinx indexer works by looping over users and copying news and edited entries into the sphinx database. Those copies are scheduled periodically using bin/schedule-copier-jobs, and also per-user when entries are created or edited. But in the latter case, the copier still searches the whole log2 table for that user's entries instead of only copying the affected entry. Does anyone know what the cost of that is compared to the indexing itself? If it's significant, http://dw-dev.dreamwidth.org/97273.html may also be used to trigger per-entry copying. Anyone has performance/resource use figures, or opinions?