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.
The order of the servers in the service definition could break the
master_accept_reads functionality.
When the first server defined in the service is a slave, it will always be
picked as the first candidate for reads. The master would only be
considered as a candidate for reads if no previous candidate was
available. For this reason, the master_accept_reads only worked when the
first server in the list was the master.
The routers no longer need to track the number of errors each DCB
receives. This is now done by the protocol modules.
The type of the DCB no longer needs to be checked in the handleError
implementation as the function is only called when a backend DCB fails.
The Avro C API fails to write bytes of size zero. A workaround is to write
a single zero byte for each NULL field of type bytes.
Also added an option to configure the Avro block size in case very large
records are written.
The rotations of binlogs weren't detected as the file names weren't
compared.
Moved the indexing of the binlogs to the end of the binlog
processing. This way the files can be flushed multiple times before they
are indexed.
The old DATETIME format wasn't processed properly which caused a
corruption of following events.
A BLOB type value could be non-NULL but still have no data. In this case,
the value should be stored as a null Avro value.
