Changes with ResultSet caused the send_databases and send_tables
functions to always return false. Also changed send_database to
return void since it shouldn't be able to fail anymore.
get_shard_target had become little bloated with the recent changes so
some routing cases were moved to their own functions. Also removed
some code that was not needed.
Replaced the previous RESULTSET with the new implementation. As the new
ResultSet doesn't have a JSON streaming capability, the MaxInfo JSON
interface has been removed. This should not be a big problem as the REST
API offers the same information in a more secure and structured way.
Add support for binary protocol prepared statements for schemarouter.
This implementation doesn't yet attempt to handle all the edge cases.
Prepared statements are routed to the server that contains the affected
tables, the internal id from the server is then mapped to the session
command id that is inceremented for each prepared statement. This unique
session command id is returned to the client because internal id given
by server might be same around different servers and this way it is
possible to keep track of them and route them to the right servers when
executed.
With the removal of the old session command implementation, the code that
used it can be removed or replaced with newer constructs. As a result, the
backend protocol no longer does any session command processing.
The three buffer types, GWBUF_TYPE_SESCMD_RESPONSE,
GWBUF_TYPE_RESPONSE_END and GWBUF_TYPE_SESCMD as well as their related
macros are no longer used and can be removed.
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.
The schemarouter now also uses versioned configurations implemented by
shared pointers to configuration objects. Moved all the configuration
management into the Config class. Removed router options from
schemarouter.
Empty databases were not mapped to ServerMap because they had no tables
to map. Modified the query to also include empty databases making it
possible to also connect to empty databases through schemarouter.
Previously schemarouter only mapped databases to the servers
they were resided on. Now all the tables are also mapped to allow the
router to route queries to the right server based on the tables used in
that query.
The two operations return different types of results and need to be
treated differently in order for them to be handled correctly in 2.2.
This fixes the unexpected internal state errors that happened in all 2.2
versions due to a wrong assumption made by readwritesplit. This fix is not
necessary for newer versions as the LOAD DATA LOCAL INFILE processing is
done with a simpler, and more robust, method.
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.
Make all modules lowercase and make module loading case
insensitive. Further, make command invocation case insensitive,
as far as the module name is conserned.
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.
Cleaned up the MaxScale version of the mysql.h header by removing all
unused includes. This revealed a large amount of dependencies on these
removed includes in other files which needed to be fixed.
Also sorted all includes in changed files by type and alphabetical
order. Removed explicit revision history from modified files.
The schemarouter should always use Backend::write for communication with
the backend servers. This keeps the backends in the correct state.
This fix solves some of the random test failures in the `sharding` test.
The schemarouter can now resolve database mapping conflicts in a
deterministic manner. This will fix the problem of central databases which
are replicated shards being assigned in a non-deterministic manner.
When the current database is implicitly used in a query that also uses an
explicit database, it must be routed to the shard which has the current
database.
As cross-shard joins are not supported, the safest, and possibly the most
expected course of action to take, is to route it to the so-called default
shard. The default shard is the shard that contains the database that is
currently set as the active database with a COM_INIT_DB, a text protocol
USE <database> query or it was set at connection time.
The schemarouter info level logging treated all queries as something that
contain SQL statements. This, for somewhat obvious reasons, cannot be
expected.
As the session commands are always appended to the end of the list, the
name should reflect that action. For this reason, the function was renamed
to append_session_command.
Readwritesplit supports replacement of slave servers by storing all
executed session commands in a list. To make the copying of this list a
bit cleaner, an overload for a list of session commands was added. This
will allow relatively smooth addition of server replacement to all router
modules that use the Backend class.
The states are now internal to the Backend class. This simplifies the use
of the class by moving the burder of state tracking to the class
itself.
Refactored the way the schemarouter uses the Backend class.
Also fixed a memory leak in the schemarouter when `ignore_databases_regex`
was used..
Using the same implementation of the Backend and SessionCommand classes in
both schemarouter and readwritesplit will prevent duplication of code.
This commit only splits the generic parts of the class to a Backend class
which the schemarouter then extends. The session commands for both routers
are similar so they require no special handling.
The default database can now be manipulated with a set of functions
exposed by the maxscale/protocol/mysql.h header. This removes the need to
handle the structures themselves in the modules and is a step towards
moving the dcb->data contents inside the session.
The server internal session id may be larger than 4 bytes (MariaDB uses 8)
but only 4 are sent in the handshake. The full value can be queried
from the server, but this query is not supported by MaxScale yet. In any
case, both the protocol and MXS_SESSION now have 64 bit counters. Only the
low 32 bits are sent in the handshake, similar to server.
