The default ECMAScript syntax appears to be broken on CentOS 7 which
effectively prevents its use in most cases. A more reliable alternative
would be to use the bundled PCRE2 library but the basic POSIX regular
expressions seem to work.
The script generates the required .avsc files without requiring a direct
connection to the database. This makes it easier to generate schemas in
more secure installations where direct access and installing dependencies
might not be easy.
The test appears to have failed at least once when the monitor did not,
for some reason, notice that a server was down. Also adjusted the queries
to be more unique across the test cases.
This commit adds a new parameter that, when enabled, prunes the session
command history to a known length. This makes it possible to keep a
client-side pooled connection open indefinitely at the cost of making
reconnections theoretically unsafe. In practice the maximum history length
can be set to a value that encompasses a single session using the pooled
connection with no risk to session state integrity. The default history
length of 50 commands is quite likely to be adequate for the majority of
use-cases.
When the connection state is reset by executing a COM_CHANGE_USER or
COM_RESET_CONNECTION, readwritesplit does not need to store the session
command history that was executed before it. With this, pooled connections
will effectively behave like normal connections if the pooling mechanism
is smart enough to reset the connection. This also prevents unwanted
visibility into the session states of other connections.
If the routing of a session command fails due to problems with the backend
connections, a more verbose error message is logged. The added status
information in the Backend class makes tracking the original cause of the
problem a lot easier due to knowing where, when and why the connection was
closed.
If a server was not chosen as the target of a routing hint, the server
status would not be logged. By logging the server state in the message, it
is easier to figure out why a server wasn't chosen as the routing target.
Both the replication lag and the message printing state are saved in SERVER,
although the values are mostly used by readwritesplit. A log message is printed
both when a server goes over the limit and when it comes back below.
Because of concurrency issues, a message may be printed multiple times before
different threads detect the new message state.
Documentation updated to explain the change.
There is a race condition between the addition of the DCB into epoll and
the execution of the event that initiates the protocol pointer for the DCB
and sends the handshake to the client. If a hangup event would occur
before the handshake would be sent, it would be possible that the DCB
would get freed before the code that sends the handshake is executed.
By picking the worker who owns the DCB before the DCB is placed into the
owner's epoll instance, we make sure no events arrive on the DCB while the
control is transferred from the accepting worker to the owning
worker.
