The previous main routing worker is now run in a separate thread.
Next step is to treat all routing workers in an identical fashion.
MainWorker is not yet used for anything, but in a subsequent change
the old housekeeper functionality will be moved in top of MainWorker.
First step in the introduction of a MainWorker. When finished, all
routing workers will run in separate threads (currently one runs in
the main thread), and the main worker run in the main thread.
Housekeeper will disappear and to the extent housekeeping tasks are
needed (where applicable they will be changed into delayed calls)
they will be run by the main worker.
Most of the ones still remaining outside are special cases.
Also, removed locking from status manipulation functions as it
has not been required for quite some time.
The process of appending to a std::string always includes a size check in
case the internal storage needs to expand. Given that we know a
canonicalized version of a query string is never larger than the original
string and that we pre-allocate enough memory to cope with the worst-case
scenario, the extra logic in std::string::push_back is unnecessary and an
extra cost. Writing directly into the string avoids this cost and improves
the performance.
Switched from default character type functions to ones that use lookup
tables. Eliminated the internal state and replaced with in-place iteration
of the query. Added code to allow single-lookup detection of normal
characters.
The log message should now contain enough information to more easily debug
any configuration issues that result from updating the main config file
after runtime changes have been done.
Also fixed the theoretical race condition in detection of persisted
configuration files by only checking for their existence once.
All global parameters are now handled by the runtime configuration
modification code. The parameters that are trivial to update can now be
updated at runtime. All other global parameters cause a new error message
to be returned stating that the parameter in question cannot be modified
at runtime.
Also updated the list of modifiable parameters in MaxCtrl. This list
should not be stored in MaxCtrl and should be created by MaxScale at
runtime.
The old behavior is to not start MaxScale if any listeners fail to
bind. This behavior is convenient when there are conflicts with other
applications so it should remain. This change prevents the internal
service restarts from functioning which might have already been broken.
The "restarting" of services after a failure to bind to an interface is
somewhat questionable. Almost no transient errors are expected at startup
with the exception of running out of sockets. This should probably be the
only case when the internal service restart is done and in other cases it
causes more harm than good.
Since we know the worst-case size of a canonical statement is the size of
the query string, we can reduce the number of memory allocations to one in
the get_canonical function.
