The connector plugin directory can now be controlled with the
`connector_plugindir` argument and configuration option. This should allow
the connector to use the system plugins if the versions are binary
compatible.
Replaced calls to mysql_options to mysql_optionsv as the former is
deprecated in Connector-C 3.0 and the latter is supported in Connector-C
2.3.
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 random number generator can be initialized when MaxScale's other
systems are being initialized. This removes the need to initialized it
when the function is used for the first time.
This header defines some general functions and maxscale main() return
values. Most of it is still public, but there were some functions
which were moved to a core header.
Moved some typedefs to router.h and server.h, changed a few
constants to these enums. Renamed some types in config.h to
remove "Gateway".
There are still some functions in the public header which are
only used in core, but they seem to fit the theme of public functions
so were not moved.
The external config.h header defined functions and structures that are
intended to be used by modules. The internal header contains functions
that are used only by the MaxScale core.
This directory is intended to be the default working directory for
relative pathname resolution. The actual implementation for
MXS_MODULE_PARAM_PATH is done at a later step.
The setting up and the initialization of the query classifier has
now been separated. The gateway explicitly sets up the query
classifier (i.e. chooses which one to use and what arguments to
provide), but the actual initialization is performed as part of
the general module initialization.
Aligning the statistics object indices to cache line size reduces the CPU
overhead of gathering the statistics. This allows the statistics to more
accurately measure the polling system without the measurement affecting
the outcome.
Router and filter instances cannot be destroyed before all worker
threads have exited. Otherwise there is a risk that data gets deleted
while someone might still be accessing it. Further, since all router
and filter instances are created by the main-thread it is better that
they are deleted by that thread as well (and not by whichever thread
happens to execute service_shutdown()). That will reduce the risk that
some unknown assumptions are violated.
The code prevented scaling by imposing global spinlocks for the DCBs and
SESSIONs. Removing this list means that a thread-local list must be taken
into use to replace it.
Because each thread has their own epoll file descriptor and only one
thread can process a DCB, it makes sense to move to a per thread zombie
queue. This removes one of the last restrictions on scalability.
The service header in include/maxscale/ contains the public part of the
service API. These functions can be safely used by the modules.
The internal header located in service/core/maxscale/ is used by the core
to initialize MaxScale at startup or to provide other services in a more
controlled way (the config_runtime, for example).
When C and C++ are mixed in a project, main() should be compiled
as C++ to ensure that all C++ static initializations are performed
properly. That may not be strictly true anymore, depending on the
used compiler and environment, but better to do that to be on the
safe side.
