How does all that changeset-stuff work out with Trac-Bzr?

We are using bzr and trac for quite a long time now and all in all we are quite happy, however the performance could be somewhat better. Therefore, I decided to migrate our trac to a different machine and to tweak the configuration a little at the same time:

First of all, I want to use postgresql instead of sqlite - I have this almost working and I hope this yields some speed-up.

Secondly, as far as I can remember, one problem of Trac-Bzr is that there is no real post-commit-hook for bazaar, so it is not possible to use "trac-admin $ENV changeset added ..." to notify trac about a new changeset. Instead it is necessary to list the repository in "repository_sync_per_request" possibly slowing down trac.

I also wanted to tackle the latter one and I wanted to use the "post_change_branch_tip"-hook of bazaar for that purpose, however the only thing trac-admin told me when adding a change set was:

NoSuchChangeset: No changeset 6 in the repository

Hm, I already set "repository_sync_per_request" to an empty value but still all the revisions were properly shown in trac. So, I tried to figure out where all that changeset-information is stored in the trac-db, however I failed - I have no clue how trac actually uses that information about a new changeset.

So, I'd like to know:

- How does the information about new changesets make its way into trac for Trac-Bzr (when I browse the source code in trac the most current information is shown, it does not seem to matter if "repository_sync_per_request" is empty or not)?

- Does it at all make sense to go for "trac-admin $ENV changeset added ..." in combination with Trac-Bzr? I thought this might speed up the whole thing significantly, but I have my doubts now.

Thank you!

Best regards,
Fabian