Oanh Nguyen, ken, if you read the `sticky` documentation, it says

If the sticky option is enabled and a "write" operation has been performed against the database during the current request cycle, any further "read" operations will use the "write" connection.

This is quite useful for same-request connections, but:
A) doesn’t really solve anything when it’s a different request (which is the problem that I presented)
B) every read operation is on the write connection. So, if the first thing you do is a log insert, all the rest of the read connections will be on the write table (slow), and they shouldn’t.