By biasing the values of all counter type scores to positive integers, the
server weights are always taken into use.
This fixes the case when weights were ignored until all score base values
were larger than zero (the mxs922_server test).
If the DCB is closed in handleError, it would be NULL in closeSession. To
only close the DCB in one place, the handleError can be reduced to writing
an error to the client and marking the failure as a fatal one.
The check for a closed session should never be needed as the core
correctly orders the calls to the module functions. The version numbering
was also not used.
Fixed the incrementation of the query counter so that it uses relaxed
atomic operations.
Replaced SPINLOCK with std::mutex where possible, leaving out the more
complex cases. The big offenders remaining are the binlogrouter and the
gateway.cc OpenSSL locks.
Removed the almost equal comparison and subsequent selection based on historical number of connections.
The effect of it was this: Select the server that has historically, weights or not, been slower. Tested this with 2.2
with maxscale on one server and mariadb:s on two servers with different network lags. The tests with historical
selects were clearly slower.
The additions into the server.h header used C++ language which caused C
programs to fail to compile. Moved the implementation of the EMAverage
class into the private Server class in the server.hh header and exposed it
via functions in the server.h header. Also temporarily moved
almost_equal_server_scores into the public server.hh as there is no
service.hh header.
See script directory for method. The script to run in the top level
MaxScale directory is called maxscale-uncrustify.sh, which uses
another script, list-src, from the same directory (so you need to set
your PATH). The uncrustify version was 0.66.
The math becomes simpler when the weight is inverted, i.e. a simple multiplication
to get the (inverse) score. Inverse weights are normalized to the range [0..1] where a lower
number is a higher weight,
The enum select_criteria_t is used to provide a std::function that takes the backends
as vector (rather than the prior pairwise compares) and returns the best backend.
Relaced router_options with configuration parameters in the createInstance
router entry point. The same needs to be done for the filter API as barely
any filters use the feature.
Some routers (binlogrouter) still support router_options but using it is
deprecated. This had to be done as their use wasn't deprecated in 2.2.
Readconnroute can now be configured at runtime. The changes to
configuration processing allow the removal of router_options now that the
parameters are parsed inside the router.
The code that selects the candidate backend always returned the root
master if the server bitmask contained the master bit. This should only be
done if the master bit is the only bit in the bitmask and when there are
other bits, the normal candidate selection code should be used.
Also added a query to the expanded test case to make sure the connection
actually works.
Up until 2.1.12, if it in the configuration file said
'router_options=slave', the master was used if there were no
slaves at session creation time.
That broke in 2.1.13 as a side-effect of MXS-1516 that checks
at routing time whether the server initially selected as master
still is the master.
Now the required server status is stored separately for each
session, so that if the master was chosen, even though we have
'router_options=slave', we can turn on the SERVER_MASTER bit.
That allows us to handle the case correctly in connection_is_valid().
The individual servers were missing a statistic that would give an
estimated query count. As there is no simple way to count queries for all
modules, counting the number of routed protocol packets is a suitable
substitute.
The use of `router_options=master,slave` was not working as expected. This
was mostly caused by the master bit checks using a bitwise AND instead of
comparing equality. In addition to this, the master would not be
considered a valid candidate if both slaves and masters were available.
If a server is removed from a service, readconnroute will not verify that
the server it is connected to is still the same root master. This fixes
the regression of MXS-1418.
A subset of the checks done at connection creation time need to be done at
query routing time. This guarantees that the connection is closed if the
server no longer qualifies as a valid candidate.
Added teset case that checks that a change in the replication topology
correctly breaks the connection.
The removal of a server from a service is intended to affect only new
sessions.
Added a test that checks that the connections are kept open even if the
server is removed from the service.
The enums exposed by the connector are not intended to be used by the
users of the library. The fact that the protocol, and other, modules used
it was in violation of how the library is intended to be used.
Adding an internal mapping into MaxScale also removes some of the
dependencies that the core has on the connector.
