WXhile still seeking why Moodle cron sometimes die (see http://tracker.moodle.org/browse/MDL-17783) we noticed fatal errors when indexing TXT, PPT or XML documents. This was easily tracked by using a "lock file" to block another run if a previous one was still running or has died for some resaons...

This is due to the fact that the three scripts search/documents/physical_xxx.php call an unkonw function "shorten" whereas it should be "shorten_text"

diff -r -b -B --exclude=tags ./search/documents/physical_ppt.php /root/web/moodle.195/search/documents/physical_ppt.php
89c89
<         $indextext = shorten($text, $CFG->block_search_limit_index_body);
—
>         $indextext = shorten_text($text, $CFG->block_search_limit_index_body);
diff -r -b -B --exclude=tags ./search/documents/physical_txt.php /root/web/moodle.195/search/documents/physical_txt.php
34c34
<         $text = shorten($text, $CFG->block_search_limit_index_body);
—
>         $text = shorten_text($text, $CFG->block_search_limit_index_body);
diff -r -b -B --exclude=tags ./search/documents/physical_xml.php /root/web/moodle.195/search/documents/physical_xml.php
37c37
<         $text = shorten($text, $CFG->block_search_limit_index_body);
—
>         $text = shorten_text($text, $CFG->block_search_limit_index_body);

Hope this will help ... this is not enough since my crons are still occasionnally dying or running for more that 30 minutes, , but much less frequently ...

Cheers.