I got same problem. I build the searchindex by
CREATE TABLE `searchindex` (
`si_page` int(10) UNSIGNED NOT NULL,
`si_title` varchar(255) NOT NULL DEFAULT '',
`si_text` mediumtext NOT NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
ALTER TABLE `searchindex`
ADD UNIQUE KEY `si_page` (`si_page`);
ALTER TABLE `searchindex` ADD FULLTEXT KEY `si_title` (`si_title`);
ALTER TABLE `searchindex` ADD FULLTEXT KEY `si_text` (`si_text`);
then maintenance/updateSearchIndex.php give me Couldn't write to the searchUpdate.MyWiki.pos! .
/updateSearchIndex.php /tmp/writable give me Couldn't write to the /tmp//writable! .
rebuildtextindex.php successfully ran, but did nothing in Table: searchindex. It's still empty any how....
I got elasticsearch installed. Is the index been wrote to elasticsearch?