When a command that changes the session state is executed on all servers and
a slave server goes down, an error message was sent to the client even though
one wasn't expected. These appeared as odd connection errors on the client side.
When a query is being routed to the slave, it is not necessary to assert that
the master server's state is still master. It is possible that the master server
changes states while the query is being routed but that doesn't affect the query
being currently routed.
The master DCB was checked for NULL-ness but the proper way is to check if
the backend reference is closed. This will fix a debug assertion in addition
to possibly preventing crashes.
The FindMariaDBConnector.cmake file now checks if the found library actually is
the MariaDB Connector-C library. If the found library is not the MariaDB
Connector-C, it will be built from source.
When the shard maps are being updated they are set into a stale state. This
means that one client connection is updating the shard maps and the information
in the shard map is not the most recent. This does mean that the information
is valid and authentication should succeed even if the shard map is stale.
The include directories previously used by MaxScale were from the embedded
library. All parts of MaxScale apart from the query classifier now use
the client libraries.
Since maxscale-common is linked to the connector-c library
and no longer to the MySql embedded library, mysql_library_init
does not need any parameters.
There can be any sort of library behind qc_init. Hence the arguments
cannot be hardwired to be like the embedded library wants them.
Eventually it might make sense to allow passing arguments from
maxscale.cnf.
Now, qc_mysqlembedded is linked against MySQL's embedded library,
and MaxScale itself against Connector-C.
So, in order to build MaxScale, Connector-C must be installed.
This has been tested with Connector-C 2.2.1.
The build variable MYSQLCLIENT_LIBRARIES is no longer used.
The query_classifier library is now only a wrapper that loads an
actual query classifier implementation. Currently it is hardwired
to load qc_mysqlembedded, which implements the query classifier
API using MySQL embedded.
This will be changed, so that the library to load is specified
when qc_init() is called. That will then allow the query classifier
to be specified in the config file.
Currently there seems to be a conflict between the mysql_library_end()
call made in qc_mysqlembedded and the mysql_library_end() call made in
gateway.c. The reason is that they both finalize a shared library.
For the time being mysql_library_end() is not called in gateway.c.
This problem is likely to go away by switching from the client
library to the connector-c library.
Now, qc_mysqlembedded is linked against MySQL's embedded library,
and MaxScale itself against Connector-C.
So, in order to build MaxScale, Connector-C must be installed.
This has been tested with Connector-C 2.2.1.
The build variable MYSQLCLIENT_LIBRARIES is no longer used.
The query_classifier library is now only a wrapper that loads an
actual query classifier implementation. Currently it is hardwired
to load qc_mysqlembedded, which implements the query classifier
API using MySQL embedded.
This will be changed, so that the library to load is specified
when qc_init() is called. That will then allow the query classifier
to be specified in the config file.
Currently there seems to be a conflict between the mysql_library_end()
call made in qc_mysqlembedded and the mysql_library_end() call made in
gateway.c. The reason is that they both finalize a shared library.
For the time being mysql_library_end() is not called in gateway.c.
This problem is likely to go away by switching from the client
library to the connector-c library.
Earlier the same (or almost the same) code was duplicated in
several places.
A conflicting declaration was also removed. There was no
implementation for that declaration.
If a password is gived as an argument, that password is shown to other users.
Changed it so that the password is copied locally and the argument cleared.
When a slave server fails to execute a session command, the log message printed
the command that was being executed as if the ERR packet was a COM_QUERY packet.
This caused corrupt strings to be printed into the error logs.
In blr_slave_callback the bits of slave->cstate are reset and
set as one transaction. Earlier they were reset in one and
set in another, leading to a situation where slave->cstate did
not contain a sensible value for a short period of time.
Further, it is now explicitly checked in blr_distribute_binlog_record
that slave->cstate indeed contains a meaningful value.
A debug assertion in the readwritesplit would always fail when the master DCB
was NULL. This was caused by the fact that the debug assertion assumes that the
pointer that is passed to it is a valid pointer.
The polling statistics collection used atomic_add to increment values. This
is not an optimal way to update statistical values. Moved to per thread
values which are summed up when they are read.
Moved the functions used to gather polling statistics to their own file and
created a specific data type for statistics.
Currently not used, but the existing query_classifier will be
changed into being just a wrapper around a dynamically loaded
query classifier plugin, i.e. qc_mysqlembedded.
Added a query classifier plugin interface using which plugins
export their functionality. Cleaned up header slightly as well.
This is the first step in the process of making the loading of
the query classifier truly dynamic.
The THREAD type was not used everywhere and pthread_t was used instead.
The thread creation function also returned the address of a stack allocated
value which isn't guaranteed to be usable.
The master DCB was used without checking if it was still open. It was possible
that the master DCB was closed and processed before the client had fully
processed all queries which caused it to fail at a debug assertion.
The fix to this is to use the client's DCB to get access to the shared session
authentication data as it is protected by additional locks.
