We upgraded to 7.0.0010 in mid-2011 from 6.2.0030. Generally speaking everything has been behaving as it should but in November, the publish started to hiccup for no apparent reason.
This was very quickly traced to our not having enough database connections configured – we were told that we’ve had the same number configured almost since we installed T4 back in 2004 but that v7 needs significantly more.
We increased from 20 to 200 and all is well once again.
The top tip? Make sure T4 / your infrastructure support people check the number of database connections allocated is appropriate for your install.