Corruption of the search index occurred so that it had to be rebuilt again. We have nearly 12 million posts and compiling the search index for that many posts takes a very long time. It is a very intensive task that places a high load on the server when it is running. So, coupled with disabling the indexing when there is a lot of traffic on the boards so that we avoid the slow loading and high loads that cause a crash, it takes weeks.
We did complete a full search index about a week ago. But the search feature was operating very slowly so more table work was done to optimize this and resolve the slowness. This created the need for yet another index to incorporate this change to the tables. But the indexing is running more quickly this time, thanks to the optimization. The indexing is disabled at high traffic times so it's not going to be done in the 2-3 days predicted it would take to complete. When? I don't know. This is all being handled by our server manager so we're just waiting and hoping it will be done by the weekend.