Sorry, there's no such feature.
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I recently merged a trac and redmine database in a way that may work for you..

Basically - i used the trac importer to create a redmine DB from the trac one. then the existing redmine DB was merged into this new one..

See the attached SQL queries as a base for what your going to need to to on the "to be deleted db" - after all these queries, you can export the data from the old db, and just insert them into the new one..

Aka - Pick one of your existing installs to the the final one and merge the other DB into it ...

The queries i used DO NOT COVER all circumstances - we has been using a limited set of trac features and a limited set of redmine features... You'll need to add more queries...!
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Note... all those numbers in the queries represent the MAX(id) from the corresponding table from the DB u pick as the "final one" ...

Eg all the 380's in the "//User IDs" section are because on the "final db" "SELECT MAX(id) AS max FROM users" returns 380...

Good luck - its not easy.
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A warnings : if you have anywhere references to ticket numbers, in text as opposed to db schema based link, then it will start pointing to a wrong location.

For example:

redmine a : commit comment : closes # 123
redmine b : commit comment : closes # 123

When merged, commit comments will stay intact, while one of them will have their tickets renumbered. This will cause some confusion.

If I can bring up my own related need : see ticket #3087
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This very closely relates to a forum post I made just yesterday about moving a single project from one Redmine install to another. I began looking at the DB to see what it would take, then just ran across this. I was thinking of a possible solution for this being a project export/import feature. This would be really helpful, either project based merger or full Redmine install.
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I just recently completed a plugin that will let you merge two Redmine database together. It worked for my customer, but I need to add some documentation before I can create a release of it. If you're interested, it's located at http://github.com/edavis10/redmine_merge_redmine
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I updated Eric Davis plugin to be compatible with current redmine version. Source code (until pull request is accepted) is located at https://github.com/chrodriguez/redmine_merge_redmine
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Hi all,

First of all, thanks to those who contributed the scripts!

I was just using Christian's version and I had problems with clashing project indexes, which was expected, so I updated project_id values in all the tables so that they would not clash, but then now I'm having the error below,

<pre>
PG::UniqueViolation: ERROR: duplicate key value violates unique constraint "projects_trackers_unique"
DETAIL: Key (project_id, tracker_id)=(4, 1) already exists.
: INSERT INTO "projects_trackers" ("project_id", "tracker_id") VALUES (4, 1)

Tasks: TOP => redmine:merge_redmine
(See full trace by running task with --trace)
</pre>

Apparently, tracker_id field is now unique in recent versions of Redmine, which is not the case at all in older database (as there are tracker_ids 1 to 4 for every single project_id). Am I missing something?

Some information,
Source Redmine: v1.2.0 (SQLite) # I converted SQLite to PostgreSQL as described in 2.2 of http://vault-tec.info/post/68670739052/installing-migrating-upgrading-redmine-with-ldap-on.
Destination Redmine: v2.5.2 (PostgreSQL)

Thanks in advance,

Cheers,
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For anyone who's trying to accomplish the same thing.
I updated the merge plugin to work with Redmine 3.0.

With this I was able to merge 2.3 and 2.5 into an up-to-date 3.0 database.
Simply migrate each redmine database to the latest version and run the plugins merge task.

https://github.com/leoc/redmine_merge_redmine

Thank you for all the work that you put into this!
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@Mr Arthur Andersen

Now that the version to upgraded to version 3.4.4, my question is whether or not the scripts still can work for it? Your reply will be highly appreciatedly.
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