About performance impact and program size: BugJail can be used also with hardcore programs, like databases and compilers, where event based record-and-replay debuggers typically struggle. There's still significant performance hit, around "twice as slow", but it won't be orders of magnitude slower.
Also, BugJail is tested with large applications. For example one test is startup sequence of Eclipse, on 5 year old box with 32GB. The result is ~700 million rows in database, in ~30 seconds. It does consume all memory, and your workstation will scream for mercy, but it gets there :)
Direct DB query is not available in current beta, but it is partially implemented in dev version: it shows the results, but there is no navigation from the query results to CallTree, Source code view etc. So: coming, but not yet.
I hope I answered your questions at least partially? It's 7AM in the morning, after one of the hottest days in Australian history, and a surprise appearance in HN front page, so I might not be quite the sharpest tool at the moment :)