Git repository indexing slowly

In a huge Git repository with more than 1100 tags and 1100 branches, the indexing is very slow and there's not much we can do to improve it.

We tried to follow this document as much as we can:
http://confluence.atlassian.com/display/FISHEYE/Tuning+FishEye

• Increased memory heap to -Xmx2048m, without success;
• We're using ssh:// protocol.
• We can't exclude paths on Git repositories.
• We tried to use the flag --Xdisable-head-detection so it will not determine branch heads in DVCS.
  We also tried to use the flag --Xdisable-tags so it will not record tags on commits in DVCS.
  These flags would make no Git tag information available in FE.
  These flags helped a little: from 30 mins dealy to 7 or 12 mins after using the startup params, but still not there yet.
• We tried increasing the polling interval, but it didn't help.

The development team suggested to open this improvement request, as we cannot do much here at the moment beyond what has already been tried and suggested.

This is a core git indexing issue in Fisheye which will need more investigation.