The std::shared_ptr type was used instead of std::tr1::shared_ptr. A NULL
pointer was also implicitly cast into a Backend pointer which caused
compilation problems on some platforms with the tr1 version of shared_ptr.
The SERVER_REF and DCB members of the Backend class are now
private. Access to the stored SERVER_REF is provided with the backend()
function. No accompanying setter function is provided as the backend
server should not change during the lifetime of the session.
The creation of the internal DCB is hidden behind the connect()
function. It simplifies the process of connecting to a server by removing
the need to manually do the bookkeeping of the server reference connection
counts. Access to the DCB is provided by the dcb() function.
The closing of the backend is done with the close() function which
contains the code that was previously in closeSession. If the backend
isn't closed when the destructor is called, it will be done
automatically. This should prevent connection leakage.
The pending command queues and the methods used to write them are now also
internal to the backends. They are simple wrappers around dcb->func.write
and the interfaces provided by the Buffer class. The mapping command queue
is still public. It needs to be combined with the generic command queue.
The schemarouter now uses shared pointers. This removes the need to copy
the class.
Following changes move the member variables inside the Backend class.
The functions that handle Backend classes are now methods of the class
itself.
Prefix all member variables with `m_` to distinct them from other
variables.
Changed the backend_ref_t struct into a Backend class. Replaced static
arrays with lists. Altered functions to make the code compile.
Further refactoring is needed, a part of the functions should be moved
into this new class.
Configuration errors can be resolved before the instance is created. This
avoids the unnecessary throws that were generated when an error occured.
As the configuration is stored in the router, the router sessions can use
a pointer to it instead of copying it locally. This should avoid some
unnecessary copying if more complex configuration parameters are added.
The use of a pointer instead of a reference conveys the message that the
lifetime of the object being pointed can, and most likely will, exceed the
lifetime of the function.
Also shuffled the member variables and internal functions around and
removed unneeded function declarations.
Cleaned up the headers, removed unused structures. Changed some members to
strings instead of char arrays. Switch to router templates should now be
easier.
The sharding implementation now uses a class to abstract the details of
the shard. This allows for different design where each session makes a
copy of the global shard map which is then used for the duration of the
session. In addition to making the desing a bit clearer to understand, it
also removes lock competition between threads.
Due to the change to C++, the main entry points need to be wrapped in the
exception-safety macros. The next step in the refactoring will be to use
the router template. This will remove the need to manually define them.
The schemarouter now uses the new session commands. It uses a standard
library container to manage the execution and storage of session commands.
The session command history is disabled until a more complete refactoring
can be done.
The binlogrouter error handling closed the DCB twice. This was caused by
the change in the way the DCB error handling is done.
The protocol modules now also call the error handling routine even if the
router session is NULL. This enables the binlogrouter to manage
authentication failures correctly instead of trying to reconnect again.
General code cleanup. Routing error detection now more robust.
Remove some unused code. Debug messages now use "unique_name" when
referring to servers.
Supports hint types:
-master
-slave
-named server
-all
A default action, which is performed when no hint exists or on error,
can be set. The different actions are analogous to the hint types.
A maximum connection number for slaves can be set. If more slaves are
configured for the service, the filter will rotate slaves for new sessions.
Within a session with multiple slaves, the "route_to_slave"-hint will
also rotate among the slave backends.
The readwritesplit now sends COM_PING queries to backend servers that have
been idle for too long. The option is configured with the
`connection_keepalive` parameter.
The static module capabilities are now used to query the capabilities of
filters and routers. The new RCAP_TYPE_NOAUTH capability is also taken
into use. These changes removes the need for the `is_internal_service`
function.
The static capabilities declared in getCapabilities allows certain
capabilities to be queried before instances are created. The intended use
of this capability is to remove the need for the `is_internal_service`
function.
The hintrouter is now in principle capable of routing requests
to the master or to some slave (in a round robin fashion) based
upon hints set by some earlier filter.
Note that as the router is completely oblivious of transaction
boundaries, using it with transactions and autocommit being off
will not make anyone happy.
Recognizing transaction boundaries using regexes and then pinning
the server until transaction commit would be needed.
Both the listeners and servers now support IPv6 addresses.
The namedserverfilter does not yet use the new structures and needs to be
fixed in a following commit.
The authenticators should have a similar way to print diagnostic
information as filter and routers do. This allows the authenticators to
print the users in their own format.
In the future, all the diagnostic entry points should be changed so that
they return a structure that contains the information in a standard
form. This information can then be formatted in different ways by other
modules.
