- Move docs from buffer.c to buffer.h
- Arguments made const-correct.
gwbuf_length
gwbuf_count
gwbuf_copy_data
- Boolean return values changes from int to bool.
gwbuf_add_property
- Meaningless returnvalue changed from int to void.
gwbuf_add_hint
- Unused function removed.
gwbuf_clone_transform
gwbuf_trim
gwbuf_clone cloned only the first buffer of a chain of buffers,
which never can be the desired outcome, while gwbuf_clone_all
cloned all buffers.
Now, gwbuf_clone behaves the way gwbuf_clone_all used to behave
and gwbuf_clone_all has been removed.
The DECIMAL value type is now properly handled in Avrorouter. It is
processed into an Avro double value when before it was ignored and
replaced with a zero integer.
Previously, server status changes from MaxAdmin would be set immediately
as long as the server lock could be acquired. This meant that it might take
several seconds until the next monitor pass is executed. Usually, this was
fine but in some situations we would want the monitor to run immediately
after the change (MXS-740 and Galera). This patch changes the logic of
setting and clearing status bits to a delayed mode: changes are first applied
to a "status_pending"-variable, and only once the monitor runs will the
setting be applied. To reduce the delay, the monitor now has a flag
which is checked during sleep (between short 0.1s naps). If set, the
sleep is cut short.
If a server is not monitored, the status bits are set directly.
There is a small possibility of a race condition: If a monitor is stopped or
destroyed before the pending change is applied, the change is forgotten.
The configuration processing requires that all parameters for monitors
exist before they are used. This is wrong if we are aiming for a modular
system but is a necessary evil for the time being.
The source and destination strings for snprintf must not overlap. A simple
check for the address of the source and destination should solve the case
where they are the same. Behavior is undefined if the pointers aren't the
same but the memory overlaps.
If no message is logged, it will be very hard to figure out where some
configurations are coming from. For this reason, it's good to log a
message whenever a persistent configuration change is taken into use.
The memory barrier is not needed here. Declaring poll_msg as volatile
should help with preveting some unwanted optimizations. Most likely
even that is unnecessary.
This came up when testing maxadmin "show servers", which is
surprisingly slow compared to the other commands. This change does
not help because the slowness is caused by the polling loop sleeping.
In a more busy environment the command would probably complete faster.
This should be looked at later.
With the addition of filter capabilities, the tee filter should work with
all sorts of routers that require at most the RCAP_TYPE_CONTIGUOUS_INPUT
capability.
Due to a recent discovery of the server's capability to process multiple
requests, the filter can safely send data from one service to another
without waiting for the earlier replies.
This also fixes a minor problem with the cloning of DCBs where the backend
DCBs could end up in the wrong thread's pool.
MXS-1060. In MaxAdmin, running "list services" will now list the
backends of each service. When running "show services", the backend
names are now printed (previously just the addresses and protocols).
When the listeners were created twice, MaxScale would crash when the users
were loaded. This is caused by the fact that the DCB for the listener is
NULL for failed listeners.
MXS-873 To prevent monitors and MaxAdmin from interfering with each other,
changes to the server status flags now happen under a lock. To avoid
interfering with monitor logic, the monitors now acquire locks to all
of their servers at the start of the monitor loop and release them
before sleeping.
A destroyed monitor should not have any servers added to it. This allows
the servers that once were monitored by a destroyed monitor to be added to
new monitors.
Adding a server to multiple monitors is forbidden. This should be detected
and reported to the end user.
The information provided by the config_runtime system to the client isn't
as detailed as it could be. Some sort of an error message stack should be
added so that client facing interfaces could properly report the reason
for the failure. Currently the only way to detect the reason of the
failure is to parse the log files.
All changes made to the configuration should be traceable. This makes the
process of understanding the life-cycle of a specific MaxScale
installation easier.
Aligning the statistics object indices to cache line size reduces the CPU
overhead of gathering the statistics. This allows the statistics to more
accurately measure the polling system without the measurement affecting
the outcome.
C++ header files have the .hh-suffix to distinguish them from C
header files, but also to allow a C++ header file (e.g. xyz.hh) for
an existing C header file (e.g. xyz.h).
- cpp.hh : Basic C++ stuff. Introduces the namespace "maxscale"
and its synonym "mxs".
- filter.[hh|cc]: Template class Filter and companion class FilterSession
to be used when implementing filters in C++.
- spinlock.h : Wrapper and lock guard class for SPINLOCK.
Router and filter instances cannot be destroyed before all worker
threads have exited. Otherwise there is a risk that data gets deleted
while someone might still be accessing it. Further, since all router
and filter instances are created by the main-thread it is better that
they are deleted by that thread as well (and not by whichever thread
happens to execute service_shutdown()). That will reduce the risk that
some unknown assumptions are violated.
Listeners are added to the list multiple times due to how DCBs are removed
from the list. This requires that an additional check is made so that we
are sure a DCB will not be added to the list twice.
There was no real need to have two separate functions for getting the
stored buffer and the target server. Combining them into one allows it to
be handled in a nicer way.
Statements can now be stored in the session object. This enables the
retrieval of these statements at a later time. These will be used by
readwritesplit to reroute failed reads to backup slaves.
This commit introduces safe session references that can be handled without
holding locks. This allows the safe searching of sessions with the unique
ID of the session.
Remove the use of raw pointers passed as strings. Change the comments of
the argument types and add more details to the parsing function
documentation.
When the client connections were listed, the DCB state was not
inspected. Only DCBs in the polling state should be printed as they are
guaranteed to be in a valid state.
Maxadmin can now create and destroy monitors. The created monitors are not
started as they would be useless without added servers and configuration
parameters.
When the monitor credentials were being written with snprintf, the source
and destination overlapped.
The serialization didn't add a 'type=monitor' line into the configuration.
The statistics of the polling system no longer match the implementation it
measures. Modified the statistics to better represent the new system by
calculating the number of epoll events each thread receives.
The polling system now has a concept of messages. This can be used to send
a synchronous message to the polling system which waits for all threads to
process the message before returning.
Currently this is used to flush unused DCBs when server persistent
statistics are reported.
Making the lists of persistent DCBs thread specific is both a bug fix and
a performance enhancement. There was a small window where a non-owner
thread could receive events for a DCB. By partitioning the DCBs into
thread specific lists, this is avoided by removing the possibility of DCBs
moving between threads.
When an epoll error occurs for a listener, the errno variable must be
stored in another variable while the listener is removed from all of the
epoll instances.
The `thread.next` pointer refers to active DCBs in the current thread's
list and the `memdata.next` pointer refers to DCBs about to be freed. The
latter was mixed up with the former due to some changes in the naming.
The code prevented scaling by imposing global spinlocks for the DCBs and
SESSIONs. Removing this list means that a thread-local list must be taken
into use to replace it.
The dcb_foreach allows a function to be mapped to all DCBs in
MaxScale. This allows the list of DCBs to be iterated in a safe manner
without having to worry about internal locking of the DCB mechanism.
