The routers no longer need to track the number of errors each DCB
receives. This is now done by the protocol modules.
The type of the DCB no longer needs to be checked in the handleError
implementation as the function is only called when a backend DCB fails.
Refactored common code into a reusable function. Now all of the backend
error handling uses the same function.
Moved responsibility of the DCB error handling tracking to the backend
protocol. The routers no longer need to manage the
`dcb->dcb_errhandle_called` variable of the failed DCB.
Removed calls to handleError with client DCBs as parameters. All of the
routers close the DCB given to handleError if it is a client DCB. The only
time the error handler would be called is when the routeQuery function
fails. The handleError call is redundant as the router already knows that
the session should be closed when it returns from routeQuery.
If one queried in MySQL MaxInfo 'show sessions' or 'show clients',
MaxScale would go in an endless loop and finally crash when memory
ran out. The reason is the rather confusing callback-based dcb-
iterating code. Adding one line fixes the issue, although the iteration
is still rather awkward with calling dcb_foreach for every session/
client.
The Avro C API fails to write bytes of size zero. A workaround is to write
a single zero byte for each NULL field of type bytes.
Also added an option to configure the Avro block size in case very large
records are written.
The rotations of binlogs weren't detected as the file names weren't
compared.
Moved the indexing of the binlogs to the end of the binlog
processing. This way the files can be flushed multiple times before they
are indexed.
The old DATETIME format wasn't processed properly which caused a
corruption of following events.
A BLOB type value could be non-NULL but still have no data. In this case,
the value should be stored as a null Avro value.
Using the class RouterSession and the template Router, a router
module can be defined. The way they are intended to be used are
as follows:
class MyRouterSession : public maxscale::RouterSession
{
...
};
class MyRouter : public maxscale::Router<MyRouter, MyRouterSession>
{
...
}
...
extern "C" MXS_MODULE* MXS_CREATE_MODULE()
{
static MXS_MODULE module =
{
...
&MyRouter::s_object,
...
};
return &module;
}
When MaxScale is started, it will attempt to create the PID directory. If
the directory does not exist and MaxScale is able to create it, MaxScale
will successfully start whereas it previously failed to do so.
If MaxScale lacks the permissions to create the directory, an error
message is printed to the user explaining the reason why MaxScale fails to
start.
The resultset of SELECTs that use functions whose result will
always vary or whose result depend upon the user executing the
query should not be cached. The list of functions is the same
as that specified for the query cache of MariaDB:
https://mariadb.com/kb/en/mariadb/query-cache/
If user or system variables are used in a SELECT statement, then
the result will not be cached. That ensures that the wrong result
will not be returned.
If all but one server in a cluster fail and `failover` is enabled for
mysqlmon, the last server would be used as if it were a master. With this
change, the restrictions on failover also require that the last server is
not configured as a slave.
This change will prevent unintended failovers from happening when network
connectivity is bad. It also allows external actors to clear the slave
configuration from the last remaining server to signal MaxScale that the
server can be used as a master.
