[edgeless]

This is what has worked for me...

Temporarily turn off forum access from the vB ACP... at Settings > Turn Your vBulletin On and Off.

If you have modified full-text variables that affect indexing or changed the stopword file itself, you must rebuild your FULLTEXT indexes after making those changes and restarting the MySQL server.

To restart the MySQL server, use the following command:

service mysql restart

Next, log into a MySQL terminal session.

To rebuild the indexes it is usually sufficient to do a QUICK repair operation with:

mysql> REPAIR TABLE searchcore_text QUICK;
mysql> REPAIR TABLE searchgroup_text QUICK;

Next, restart the MySQL server again:

service mysql restart

Next, rebuild your FULLTEXT indexes. To rebuild your indexes, you need to run the follow queries in sequence...

But before doing so, emptying your search tables will speed things up. The queries to empty the tables are:

truncate searchcore;
truncate searchcore_text;
truncate searchgroup;
truncate searchgroup_text;

Next you need to drop the old indexes off the tables. To drop the indexes, use the following commands:

drop index text on searchcore_text;
drop index grouptitle on searchgroup_text;

Finally, you need to build new indexes. To recreate the specific indexes, use the following commands:

CREATE FULLTEXT INDEX text ON searchcore_text (title, keywordtext);
CREATE FULLTEXT INDEX grouptitle ON searchgroup_text (title);

You can then go to your vB ACP and do an interface-executed rebuild session from there. To do this, go to the Maintenance > General Update Tools section of your vBulletin ACP. You optionally may want to empty the indexes from there before starting the rebuild process.


Note: My search functionality wouldn't fully return until I did the following.

Go to the Maintenance > Repair / Optimize Tables section of your vBulletin ACP and optimize the post and thread word tables.

Next, you should probably then go to the Forums & Moderators > Forum Blocks Manager section of your vB ACP and click on Reload Block Types.

Finally, re-enable your general forum access from the vB ACP at Settings > Turn Your vBulletin On and Off.

Done.

--------------- Added [DATE]1423066500[/DATE] at [TIME]1423066500[/TIME] ---------------

One more noteworthy observation... I have noticed that after performing the above steps, there has been a significant latency period before the search function returned to normal. I'm assuming that such 'lag' to gain back correct search functionality is related to size of the particular database and the processor speed of the hosting machine in conjunction and how quickly those elements can complete the necessary work to restructure the indexes for the entire database. But that's merely a guess on my part. The main point is that once you've performed the above steps, you may want to give it a bit of time before concluding that things haven't changed.