Having enabled global search, and having ensured that the extra libraries were in the correct place, I ran the iondexer test - it appeared to show no problems, so I tried to run the indexer for the first time. All I got was output similar to this:

Server Time: Tue, 01 Apr 2008 18:11:21 +0100

Warning: Indexing was not successfully completed last time, restarting.

Using /home/httpd/vhosts/web2/moodledata/search as data directory.
Deleting old index entries.
Starting activity modules

28 modules found.
41 blocks found.
Processing module function chat_get_content_for_index ...

...and nothing else.

Looking at the php error logs shows this:

[Tue Apr 01 18:11:21 2008] [error] [client 81.179.17.193] PHP Fatal error: Uncaught exception 'Zend_Search_Lucene_Exception' with m
essage 'Index compound file doesn't contain _0.del file.' in /home/httpd/vhosts/web2/web/search/Zend/Search/Lucene/Index/SegmentInfo
.php:258\nStack trace:\n#0 /home/httpd/vhosts/web2/web/search/Zend/Search/Lucene/Index/SegmentInfo.php(206): Zend_Search_Lucene_Inde
x_SegmentInfo->openCompoundFile('.del')\n#1 /home/httpd/vhosts/web2/web/search/Zend/Search/Lucene/Index/SegmentWriter/DocumentWriter
.php(209): Zend_Search_Lucene_Index_SegmentInfo->__construct('_0', 3, Object(Zend_Search_Lucene_Storage_Directory_Filesystem))\n#2 /
home/httpd/vhosts/web2/web/search/Zend/Search/Lucene/Index/Writer.php(434): Zend_Search_Lucene_Index_SegmentWriter_DocumentWriter->c
lose()\n#3 /home/httpd/vhosts/web2/web/search/Zend/Search/Lucene.php(1010): Zend_Search_Lucene_Index_Writer->commit()\n#4 /home/http
d/vhosts/web2/web/search/indexer.php(178): Zend_Search_Lucene->commit()\n#5

\n thrown in /home/httpd/vhosts/web2/web/search/Z
end/Search/Lucene/Index/SegmentInfo.php on line 258, referer: http://edu-demo.pteppic.net/search/stats.php

Any ideas?

I know that this is still experimental, and I am not relying on this for any production sites, but I can't even get it partly working for demonstrations...and yet other people in the forums and tracker seem to have got much further than this.

Am I missing some libraries, php extensions or something?

Sean K