If the DCB was closed before the handshake for the LocalCliet connection
was received, the gw_decode_mysql_server_handshake would use the closed
DCB to log the connection ID. Clearing out the pointer prevents it.
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.
Given that worker.hh was public, it made sense to make routingworker.hh
public as well. This removes the need to include private headers in
modules and allows C++ constructs to be used in C++ code when previously
only the C API was available.
The LocalClient micro-client required a reference to the session that was
valid at construction time. This is the reason why the previous
implementation used dcb_foreach to first gather the targets and then
execute queries on them. By replacing this reference with pointers to the
raw data it requires, we lift the requirement of the orignating session
being alive at construction time.
Now that the LocalClient no longer holds a reference to the session, the
killing of the connection does not have to be done on the same thread that
started the process. This prevents the deadlock that occurred when
concurrect dcb_foreach calls were made.
Replaced the unused dcb_foreach_parallel with a version of dcb_foreach
that allows iteration of DCBs local to this worker. The dcb_foreach_local
is the basis upon which all DCB access outside of administrative tasks
should be built on.
This change will introduce a regression in functionality: The client will
no longer receive an error if no connections match the KILL query
criteria. This is done to avoid having to synchronize the workers after
they have performed the killing of their own connections.
The id has now been moved from mxs::Worker to mxs::RoutingWorker
and the implications are felt in many places.
The primary need for the id was to be able to access worker specfic
data, maintained outside of a routing worker, when given a worker
(the id is used to index into an array). Slightly related to that
was the need to be able to iterate over all workers. That obviously
implies some kind of collection.
That causes all sorts of issues if there is a need for being able
to create and destroy a worker at runtime. With the id removed from
mxs::Worker all those issues are gone, and its perfectly ok to create
and destory mxs::Workers as needed.
Further, while there is a need to broadcast a particular message to
all _routing_ workers, it hardly makes sense to broadcast a particular
message too _all_ workers. Consequently, only routing workers are kept
in a collection and all static member functions dealing with all
workers (e.g. broadcast) have now been moved to mxs::RoutingWorker.
Now, instead of passing the id around we instead deal directly
with the worker pointer. Later the data in all those external arrays
will be moved into mxs::[Worker|RoutingWorker] so that worker related
data is maintained in exactly one place.
A new class mxs::Worker will be introduced and mxs::RoutingWorker
will be inherited from that. mxs::Worker will basically only be a
thread with a message-loop.
Once available, all current non-worker threads (but the one
implicitly created by microhttpd) can be creating by inheriting
from that; in practice that means the housekeeping thread, all
monitor threads and possibly the logging thread.
The benefit of this arrangement is that there then will be a general
mechanism for cross thread communication without having to use any
shared data structures.
The DCB pointer in the MySQLProtocol struct doesn't appear to be updated
in all cases which causes it to be an unreliable source. As the session
itself is always available and it always has the service pointer properly
set, it should be used instead.
Also removed the dead protocol compression code and replaced the
parameters with the service capability bits.
If a shallow copy of the buffer is made, any modifications that are made
to the data after it has been queued will affect the queued query of the
LocalClient.
A copy-on-write mechanism would save the relatively expensive process of
copying the data but since the LocalClient is not often used, it is not
the most critical performance problem.
The internal header directory conflicted with in-source builds causing a
build failure. This is fixed by renaming the internal header directory to
something other than maxscale.
The renaming pointed out a few problems in a couple of source files that
appeared to include internal headers when the headers were in fact public
headers.
Fixed maxctrl in-source builds by making the copying of the sources
optional.
KILL commands are now sent to the backends in an asynchronous manner. As
the LocalClient class is used to connect to the servers, this will cause
an extra connection to be created on top of the original connections
created by the session.
If the user does not have the permissions to execute the KILL, the error
message is currently lost. This could be solved by adding a "result
handler" into the LocalClient class which is called with the result.
