Solr

M. Balridge
Wed, 02 Jan 2019 08:59:20 -0000

> The main problem is : After some time of indexing from Dovecot, Dovecot
> returns errors (invalid SID, etc...) and Solr return "out of range
> indexes" errors

I've been watching the progress of this thread with no small concern, mainly
because I've been tasked with providing a server-side email search facility
with a budget and manpower level that comes down to mainly *1*, i.e., me.

I was expecting, given the strongly worded language about "just use
lucene/SOLR" and "ignore squat", that I should invest time +
effort into this
JAVA nightmare that is SOLR.

I started with squat and another word-indexor system that used out-of-band
(not a dovecot plugin) software to provide rapid (sub-second) searches through
tens-of-GB-scale mailboxes.

Unlike what I was led to believe, the squat indexes worked surprisingly well,
once you sorted out the odd resource size (ulimit-related) issues (vsz &
friends) limitations. I did notice the "worst-case" search performance
have
worryingly high O(x) increases in time, but I'd not seen anything that was a
dealbreaker. It goes without saying that various substring searches worked as
expected, for the most part.

My experiences with SOLR were similar to Messr. Moreau's: lots of startup
errors with provided schemata files. Lots of JAVA nonsense issues. Lots of
sensitivity to WHICH Java runtime, etc, etc. I finally fixated a specific JVM,
version of SOLR, and dovecot to find the "best" working combination,
only to
find that the searches didn't work out as expected. I expected to be able to
do date-ranging based searches. Didn't work. I expected to search CONTENTS
of
emails, and despite many days of tweaks, I couldn't get it to index even the
basics like filenames/types of attachments, so I could exposed
attachment-based searching to my users.

So, without rancour or antipathy, I ask the entire list: has ANYONE gotten a
Dovecot/solr-fts-plugin setup to work that provides as a BASELINE, all of the
following functionality:

1) The ability to search for a string within any of the structured fields
(from/subject) that returns correct results?

2) The ability to search for any string within the BODY of emails, including
the MIME attachment boundaries?

3) The ability to do "ranging" searches for structures within emails
that
decompose to "dates" or other simple-numeric data?

OPTIONALLY, and this is probably way outside of the scope of the above,
despite the fact that it's listed as a "selling point" of SOLR
versus other
full text search engines:

4) The ability to do searches against any attachments that are able to be
post-processed and hyper-indexed by SOLR+Tika?

-------------

SOLR seems to have "brand cachet", so presumably it actually works
(for somebody).

Dovecot has not a little "brand cachet", and for me, I have innate
faith and
trust in Timo and his software. I am no stranger to the "costs" of
"free"
software, in that you sacrifice your own blood, sweat, and tears just to get
these disparate pieces to work together.

I *DO* respect that Timo has to keep the lights (and sauna) on in Finland.
Maybe there's a super-secret (no advertised prices, "carrier-only"
price list)
with _Dovecot, Oy_ wherein the above ARE actually available for something less
than 6.022 x 10^23 Euros per centi-second of licencing fees.

But please, level with us faithful users.  Does this morass of Java B.S.
actually work, and if not, please just deprecate and remove this moribund
software, and stop trying to bury the only FTS plugin many of us HAVE actually
gotten to work.  (Pretty please?)

I respect that Messr. Moreau has made an earnest effort to get this JAVA B.S.
to actually work, as I have.

He persevered where I'd given up. He's vocal about it, and now I'm
chiming in
that this ornate collection of switchblades only cuts those who try to use them.

Respectfully,
=M=