The session command history is now compacted to contain only the first and
last execution of a session command. This should still allow most of the
more eccentric use-cases of user variables while keeping the session
command history smaller.
Added some convenience functions into the SessionCommand class to make the
pruning process easier.
Moved session command execution into the Backend class itself as the
session commands are defined as a related part of it. This allows all
connections to execute session commands if some are available.
Removed explicit SERVER_REF usage in the readwritesplit connection
creation code and replaced it with SRWBackend. This allows the removal of
the get_root_master_backend function which duplicated the functionality in
get_root_master.
The Backend::dcb() method gives the raw pointer to the internal DCB. This
pointer is used by at least readwritesplit to map raw DCB pointers to
backends. To prevent stale pointers from being returned, m_dcb needs to be
set to NULL after it has been closed.
From a practical perspective it makes no relevant difference
whether you have to add an entry to the config file and restart
maxscale or if you have to restart maxscale and provide a specific
command line, so better to provide just either possiblity.
More important would be to provide a way for turning this feature
on and off at runtime.
With the configuration entry
dump_last_statements=[never|on_close|on_error]
you can now specify when and if to dump the last statements
of of a session.
With the configuration entry
retain_last_statements=<unsigned>
or the debug flag '--debug=retain-last-statements=<unsigned>',
MaxScale will store the specified number of last statements
for each session. By calling
session_dump_statements(session);
MaxScale will dump the last statements as NOTICE messages.
For debugging purposes.
If a MaxScale-generated configuration defines an empty value, it is
ignored with the assumption that the next modification will cause the
problem to correct itself.
Disabling the session cache prevents errors from being generated as the
default OpenSSL configuration is to enable session caching but with an
uninitialized context ID. In addition to preventing the errors, it
prevents the possible security problems implicated by the definition a
"static" context ID.
- session_set_response() made const correct
- set_response() function added to mxs::FilterSession; calls
session_set_response().
- Cache uses set_response() for delivering the cache result
to the client.
Filter that terminate the response processing now have a mechanism
using which a response can be provided in such a way that previous
filters will see the response.
The macros MXS_SESSION_ROUTE_QUERY and MXS_SESSION_ROUTE_REPLY
are now defined in terms of functions that do the actual stuff.
Incidentally, the function session_route_reply() existed already
but was not used. Now slightly rewritten so that it does not simply
ignore misuse.
We need to copy some data from a AF_UNIX based listener dcb
to the accepted client dcb, to prevent assertion violation in
dcb_get_port(). Further, to be able to log the path in the case
of an authentication error we need to copy that as well.
The canonicalization process now strips non-executable comments from the
SQL and replaces all constants in executable comments.
Enabled the comment test and updated expected output of the select and
alter tests.
Updated tests with new expected output. Also took new function into use
and removed the old one.
Since the comment removal isn't added yet, one of the tests is expected to
fail and it is temporarily disabled.
The new canonicalization function now processes negative numbers
correctly. It uses a look-behind operation to detect whether the operation
is a negation of a number or a subtraction from another value.
The function uses a hand-written parser that picks out the values and
replaces them with question marks. This function is not yet able to
process negative values; a `-?` token will be generated for all negative
numbers.
The new function will canonicalize the query in such a way that string and
number constants cannot be distinguished which means that it won't pass
the current test cases.
Cleaned up and updated the test; the code was written with a pre-C99
standard in mind.
Added a get() method into mxs::Buffer to make it easier to use with
non-C++ functions.
Add missing listener JSON diagnostics call. Check that the
diagnostics_json function exists before calling it.
As the protocol modules don't have diagnostics functions, they aren't
called.
Replace hard-coded strings with constant parameters. This makes it
slightly cleaner.
The earlier @maxscale.cache.enabled has now been replaced with
@maxscale.cache.populate and @maxscale.cache.use that provide
for more flexibility.
With the former it is possible to control in what circumstances
the cache is populated and with the latter one when it is used.
Together they can be used for having a completely client driven
caching.
With the changes in this commit it is possible to add and remove
MaxScale specific user variables. A MaxScale specific user variable
is a user variable that is interpreted by MaxScale and that
potentially changes the behaviour of MaxScale.
MaxScale specific user variables are of the format "@maxscale.x.y"
where "@maxscale" is a mandatory prefix, x a scope identifying the
component that handles the variable and y the component specific
variable. So, a variable might be called e.g. "@maxscale.cache.enabled".
The scope "core" is reserved (although not enforced yet) to MaxScale
itself.
The idea is that although MaxScale catches these, they are passed
through to the server. The benefit of this is that we do not need to
detect e.g. "SELECT @maxscale.cache.enabled", but can let the result
be returned from the server.
The interpretation of a provided value is handled by the component that
adds the variable. In a subsequent commit, it will be possible for a
component to reject a value, which will then cause an error to be
returned to the client.
There are 3 new functions:
- session_add_variable() using which a variable is added,
- session_remove_variable() using which a variable is removed, and
- session_set_variable_value().
The two former ones are to be called by components, the last one by
the protocol that catches the "set @maxscale..." statements.
If two services referred to the same filter instance, it would
cause the filter to deleted twice at MaxScale shutdown with a
crash as the result.
Now when the services are deleted we just collect the unique
filter instances and then delete them after all services have
been deleted.
Earlier, if a service had multiple listeners you would have had
MaxScale> show dbusers MyService
User names: alice@% ...
User names: bob@% ...
That is, no indication of which listener is reporting what. With
this commit the result will be
User names (MyListener1): alice@% ...
User names (MyListener2): bob@% ...
Further, the diagnostics function of an authenticator is now expected
to write the list of users to the provided DCB, without performing any
other formatting. The formatting (printing "User names" and appending
a line-feed) is now handled by the handler for the MaxAdmin command
"show dbusers".
If local address has been specified, then all connections created
using mxs_mysql_real_connect() will use that same local address as
well.
A system test has not been created as our VMs do not have more than
one usable IP-address. Locally it has been verified to work as
expected.
The variable containing the number of workers must be updated
only after the workers have been successfully created.
Failure to do this led to crash in Worker::shutdown_all() if a
terminating signal was received after the worker initialization
had failed.
Instead of trying to figure out whether the kernel supports O_DIRECT
in conjunction with pipes, let's just use it and if it fails, try
without O_DIRECT.
Case in point, based on circumstantial evidence it seems that in a
container context, it may appear as if the kernel supports O_DIRECT
when it in reality does not. So better to use brute-force.
