With the addition of SO_REUSEPORT support, it is no longer possible to
rely on the network stack to prevent multiple listeners from listening on
the same port. Without explicitly checking for the ports it would be
possible for two listeners from two different services to listen on the
same port in which case the service would be almost randomly chosen.
If SO_REUSEPORT is available and the kernel supports it, listeners will
now listen on separate file descriptors. This removes the need for
cross-worker communication when in normal operation which should make
MaxScale scale better.
By storing the file descriptor inside a worker-local variable, it is
possible to handle both unique file descriptors (created with
SO_REUSEPORT) and shared file descriptors with the same code. The way in
which the file descriptor is stored in the rworker_local object determines
the way the listener behaves.
The function allocated a constant-sized chunk of memory for all messages
which was excessive as well as potentially dangerous when used with large
strings.
The creation of a monitor from JSON relied on the non-JSON version for the
addition of default parameters but it proceeded to check the validity of
the parameters before it. Whenever parameters are checked, the default
parameters should be present.
If the last server was removed, the parameter would be rejected due to it
being empty. To remove the parameter, the
MonitorManager::reconfigure_monitor should be used. Also fixed the
unnecessary serialization after a failure to remove server from a monitor
and the fact that some errors were logged instead of written to the caller
of the command.
This way the state is encapsulated in the object and the required changes
are done in one place. This makes the code reusable across all functions
making it easier to implement better monitor alteration code.
Increasing counter sizes from int to long for averages.
Rename random functions to end with _co instead of _exclusive to
indicate range [close, open[, and to allow future suffixes oc, cc and oo.
When default parameters are loaded, the type and module name are
added. This helps object serialization and allows all the code to expect
that all the parameters needed to create an object are always present.
By passing strings instead of const char pointers to the task control
functions, we can safely make copies of them knowing that the contents
won't disappear.
The last server wasn't removed as the set of relationships was empty. In
addition to this, changes to relationships via the relations endpoint
wasn't reflected by the monitor parameters.
If a monitor was created at runtime, it was missing some parameters that
were assumed to be always present. In addition to that, the parameters
weren't validated against the list of common and module parameters.
Since the monitors always reconstruct the server list, the new servers can
be stored as a parameter. To make this possible, the
server_relationship_to_parameter helper function is needed.
This commit fixes the MaxCtrl test suite failures but does not fix the
failures in the REST API test suite.
Reactivating monitors shouldn't be done as it's simpler to actually
destroy and create a new one. The performance of reactivation is
insignificant compared to the possible inconsistency problems it allows.
Storing all the runtime errors makes it possible to return all of them
them via the REST API. MaxAdmin will still only show the latest error but
MaxCtrl will now show all errors if more than one error occurs.
Added an overload to execute_concurrently that takes an std::function as a
parameter and added a const version of operator* for rworker_local. Also
removed the std::move of the return value in rworker_local::values as it
can prevent RVO from taking place.
Alterations to monitors are now done with all changes present in the first
call to configure. This fixes the case where two parameters depended on
each other and one would get configured before the other.
Uncrustify always forced insertion of tabs which led to mangled formatting
of the parameters. Placing each part on a separate line seems to work
better and produce a more readable output.
The functions are now in MonitorServer. Disk space can only be checked
during specific ticks. If a server misses a tick (e.g. is down) it will
be checked after disk_space_check_interval has passed.
The rank can now only be used to define two groups of servers: primary and
secondary servers. This limits the exposure and reduces the number of
possibilities that can arise from the use of this parameter thus making it
more predictable.
The helper function makes it easier to convert enum values at runtime to
their integer representation. Also changed the configuration processing
code to use the new function.
Although the default value is the maximum value of a signed 32-bit
integer, the value is stored as a 64-bit integer. The integer type
conversion functions return 64-bit values so storing it as one makes
sense.
Currently values higher than the default are allowed but the accepted
range of input should be restricted in the future.
Given the following query:
PREPARE ps FROM 'PREPARE ps2 FROM \'SELECT 1\'';
The debug assertion is hit even though this is valid, albeit unsupported,
SQL. An optimization would be to ignore the query if the prepared
statement type is another prepared statement.
