Selecting pool using custom protocol over SSL

This really sounds like ID 224958, which is fixed in 10.2.0 HF2. Basically, SSL::collect is (erroneously) not holding up the connection, so a server pick is attempted before CLIENTSSL_DATA ever fires, and since there's no pool (since you're trying to specify one in CLIENTSSL_DATA), the connection fails. Also, as you've found, you can't just specify a pool earlier, because the server connection will already be established (or be in the process of getting established) by the time CLIENTSSL_DATA fires. You *might* be able to do something like specify a default pool, and then when CLIENTSSL_DATA fires do an LB::detach and then specify a new pool, but I'd do a lot of testing before putting that sort of a solution into production. Your best bet is to just upgrade. Hope this helps!