This is the summary of my work with SOLR-Dovecot, in my quest to reproduce the previoulsy excellent work of fts_squat

@Aki : Based on the time I have spent on this, I would love to see you updating the Wiki with those improvements, and adding my name somewhere

@All : Hope it helps

- Installation:

-> Create a clean install using the default, (at least in the Archlinux package), and do a "sudo -u solr solr create -c dovecot ". The config files are then in /opt/solr/server/solr/dovecot/conf and datafiles in /opt/solr/server/solr/dovecot/data

-> In /opt/solr/server/solr/dovecot/conf/solrconfig.xml:

* around line 313, change <openSearcher>false</openSearcher> to <openSearcher>true</openSearcher>

* around line 147, set <writeLockTimeout>2000</writeLockTimeout> (or above)

* around line 1127, before <updateProcessor class="solr.UUIDUpdateProcessorFactory" name="uuid"/>, add <schemaFactory class="ClassicIndexSchemaFactory"></schemaFactory>

* around line 1161, delete the whole <updateProcessor class="solr.AddSchemaFieldsUpdateProcessorFactory" name="add-schema-fields">

* around line 1192, remove the whole <updateRequestProcessorChain name="add-unknown-fields-to-the-schema" ... />

-> Remove /opt/solr/server/solr/dovecot/conf/managed-schema

-> Change "schema.xml" by the one below to reproduce fts_squat behavior (equivalent to " fts_squat = partial=3 full=25" in dovecot.conf) (note : such a huge trouble to replace a single line setup, anyway...)

-> Move /opt/solr/server/solr (or the subfolder data) to a partition with *space*, ideally ext4 or faster file system (it looks like Solr is not considering using a simple mysql database, which would make sense to avoid all the fuzz and let it transit to a non-java state, but that is another story)

-> Config of dovecot.conf is as below

-> The systemd unit shall specify high ulimit for files and proc (see below)

-> Increase the memory available for the JavaVM (I put 12Gb as I have quite a space on my server, but you may adapt it as per your specs) : in /opt/solr/bin/solr.in.sh, set SOLR_HEAP="12288m"

-> As Solr is complaining a lot, you may consider a filter for it in your syslog-ng or journald as it pollutes greatly your audit files

-> (re)Start solr (first) and dovecot by systemctl

-> Launch redindex ( doveadm fts rescan -u <username> )

-> wait for a big while to let the system re-index all your mail boxes

- Bugs so far

-> Line 620 of fts_solr dovecot plugin : the size oof header is improperly calculated ("huge header" warning for a simple email, which kilss the index of that considered email, so basically MOST emails as the calculation is wrong)

-> The UID returned by SOlr is to be considered as a STRING (and that is maybe the source of problem of the "out of bound" errors in fts_solr dovecot, as "long" is not enough)

-> Java errors : A lot of non sense for me, I am not expert in Java. But, with increased memory, it seems not crashing, even if complaining quite a lot in the logs

-------SCHEMA.XML in /opt/solr/server/solr/dovecot/conf

<?xml version="1.0" encoding="UTF-8"?>
<schema name="dovecot" version="2.0">
<uniqueKey>id</uniqueKey>
<fieldType name="dovecottext" class="solr.TextField" autoGeneratePhraseQueries="true" positionIncrementGap="100">
<analyzer type="index">
<tokenizer class="solr.ClassicTokenizerFactory"/>
<filter class="solr.WordDelimiterGraphFilterFactory" catenateNumbers="1" generateNumberParts="1" splitOnCaseChange="1" generateWordParts="1" splitOnNumerics="1" catenateAll="1" catenateWords="1" preserveOriginal="1"/>
<filter class="solr.FlattenGraphFilterFactory"/>
<filter class="solr.LowerCaseFilterFactory"/>
<filter class="solr.TrimFilterFactory"/>
<filter class="solr.RemoveDuplicatesTokenFilterFactory"/>
</analyzer>
<analyzer type="query">
<tokenizer class="solr.KeywordTokenizerFactory"/>
<filter class="solr.LowerCaseFilterFactory"/>
<filter class="solr.TrimFilterFactory"/>
<filter class="solr.RemoveDuplicatesTokenFilterFactory"/>
</analyzer>
</fieldType>
<fieldType name="dovecotfield" class="solr.TextField" autoGeneratePhraseQueries="true">
<analyzer type="index">
<tokenizer class="solr.ClassicTokenizerFactory"/>
<filter class="solr.NGramFilterFactory" minGramSize="3" maxGramSize="25"/>
<filter class="solr.TrimFilterFactory"/>
<filter class="solr.LowerCaseFilterFactory"/>
<filter class="solr.RemoveDuplicatesTokenFilterFactory"/>
</analyzer>
<analyzer type="query">
<tokenizer class="solr.KeywordTokenizerFactory"/>
<filter class="solr.LowerCaseFilterFactory"/>
<filter class="solr.TrimFilterFactory"/>
<filter class="solr.RemoveDuplicatesTokenFilterFactory"/>
</analyzer>
</fieldType>

-- DOVECOT.CONF

mail_plugins = fts fts_solr

plugin {
plugin = fts fts_solr managesieve sieve

fts = solr
fts_autoindex = yes
fts_enforced = yes
fts_solr = url=http://127.0.0.1:8983/solr/dovecot/

(replace 127.0.0.1 by your solr server if you want to use an external server)
(...)

}

-- /etc/systemd/system/multi-user.target.wants/solr.service

[Unit]
Description=Solr full text search engine
After=network.target

[Service]
Type=simple
User=solr
Group=solr
PrivateTmp=yes
WorkingDirectory=/opt/solr
LimitNOFILE=65000
LimitNPROC=65000
ExecStart=/opt/solr/bin/solr start -f

[Install]
WantedBy=multi-user.target