Intended to be used from fatal signal handlers. As the statement will
be returned only while classification is in process, if a statement
is returned, it is an indication that the crash was caused by the
classification.
If the protocol routes a COM_QUIT packet to the backend, it must not
generate a packet when it is shutting down. This could cause unexpected
write errors if the backend server managed to close the socket before the
write was done.
By deferring the closing of a DCB until the protocol tells that it's in a
stable state, we avoid closing the connection mid-authentication. This
makes sure that all connections have reached a stable state before they
are closed which in turn prevents the connections from counting towards
aborted connects (or failed authentications like it did with the old fix).
If a DCB is expecting a response from the server, it must not be placed
into the connection pool. This prevents the case where unexpected
responses would be delivered to DCBs taken out of the connection pool.
The charset sent in the handshake is now done with the following
priorities:
* First Master server
* Last Slave server
* First Running server or Down server whose charset is known
The change is that server in the Down state to which we've successfully
connected to can also be used as the charset source. This, in addition
with an "empty" default charset, helps avoid the use of the default latin1
charset unless absolutely necessary.
The mon_ping_or_connect_to_db resets the MYSQL handle which caused the
loss of the error message. Returning a new enumeration value for
authentication errors solves this problem.
The backend didn't expect AuthSwitchRequest packets in response to the
handshake response packets. This is allowed by the protocol and appears to
happen with at least MySQL 8.0.
The Connector-C was changed to always return only the client's charset,
not the actual charset that the connection ends up using. To cope with
this, the code has to use SQL to join the default character set name to
the default collation for it which can be used to extract the numeric ID
of the charset.
The password values are now masked with asterisks. This tells whether a
password is set or not but it does not expose any information about the
password itself.
The errors that are ignored by readwritesplit are now stored as the
current close reason in the Backend. This allows the information about the
error to be retained and it can be used later in the error handler to
display the true reason why the connection was closed.
The hangup and error handlers now have unique messages. Although the
behavior in the handlers is practically the same in both cases, the cause
of the error is not the same.
If a socket error is present, it is added to the error message. If an
error is present, it should clearly show the reason why the TCP socket was
closed.
The is_fake_event boolean helps distinguish fake events from real
ones. This makes figuring out the real source of hangup events easier.
The use of a regular expression allows multiple rewrite rules to be
combined into one. This allows more versatile conversions but, given the
simple nature of regular expressions, also makes accidental changes more
likely.
Addd mxs::pcre2_substitute that is a more C++-friendly version of
mxs_pcre2_substitute to make. This makes string replacement a lot easier
to do when the source and destination are not C strings.
The gwbuf_hexdump_pretty displays the hex contents of the buffer alongside
the human-readable version of it. The text version helps identify parts of
the buffer that contain text which makes protocol data decoding easier.
Added new ssl_version value for TLSv1.3. This allows the list of accepted
protocol versions to be limited to all supported protocols. Previously
TLSv1.3 was only available with ssl_version=MAX.
Also fixed the enum value serialization to use a lowercase v. This causes
them to have the same value as the one used in the enum.
Previously when ssl_version was used with a value that is not supported on
the system, an unknown parameter error was returned. This could be
confusing and logging a proper error message should make it clear.
