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.
It is now impossible to create two listeners for a service that
would listen on the same port/socket (as before), but the error
message is now sensible and provides detailed information to the
user.
Previously, if the list contained servers that were not monitored by
the monitor yet were valid servers, an error value would be returned
and the monitor failed to start.
With this update, the non-monitored servers are simply ignored when
forming the final list.
Also, added printing of the list to diagnostics.
Now the users will be reloaded at most once during each
USERS_REFRESH_TIME period. Earlier they could be reloaded at
at most USERS_REFRESH_MAX_PER_TIME times, which in practice meant
that with repeated unauthorized login attempts they were reloaded
N times in rapid succession, without the situation being likely to
change in between.
The error regarding the refresh rate having been exceeded
error: [RWSplit] Refresh rate limit exceeded ...
has been turned into a warning. Further, the warning will be
logged at most once per refresh period that currently is 30s.
The MariaDB Connector-C headers that are built by MaxScale must be
included before any system headers.
Fixed code that explicitly included the <mysql.h> header to use the
<maxscale/protocol/mysql.h> wrapper instead.
"servers_no_promotion" is a comma-separated list of servers
which cannot be chosen when selecting a new master during failover
(auto or manual), or when automatically selecting a new master
for switchover (currently disabled).
The servers in the list are redirected normally and can be promoted
by switchover when manually selecting a new master.
If the API versions do not match, MaxScale will treat this as an
error. The API versioning would allow backwards compatible changes but the
functionality to handle that is not implemented in MaxScale.
Updated API versions based on changes done to module APIs in 2.2.
With the flag --debug=enable-statement-logging it is now possible
to instruct MaxScale to log all SQL statements it sends to the
servers.
The format of the logged string looks like:
notice : SQL(127.0.0.1): 0, "SELECT ..."
First the fixed string "SQL", followed by the server address in
parenthesis followed by the actual return value of mysql_query(),
followed by the statement itself.
The "SQL" string makes the lines easy to grep for and having the
return value before the statement makes it easier to spot since
the length of the return value string does not wary much, but the
length of the statements do wary a lot.
* MXS-199: Support Causal Read in Read Write Splitting
* move most causal read logic into rwsplit router and get server type from monitor
* misc fix: remove new line
* refactor, move config to right place, replace ltrim with gwbuf_consume
* refacter a little for previous commit
* fix code style
In some cases you might want to use a specific address/interface
when connecting to a server instead of the default one. With the
global parameter 'local_address' it can now be specified which
address to use.
Now detects some erroneous situations before starting switchover.
Switchover can be activated without specifying current master.
In this case, the cluster master server is selected.
All modules now have an 8-bit range for capability flags. Currently only
the client side authenticator and protocol capability bits are loaded due
to the fact that backend versions of these modules don't relate to a
particular service.
The new parameter allows ignoring of master servers that are external to
the monitor configuration. This allows sub-trees of the actual replication
tree to be used as fully fledged replication trees.
The state of the monitored servers is only persisted if the states of the
servers have changed. This removes the unnecessary disk IO caused by the
writing on the monitor journal.
The new `ssl_verify_peer_certificate` parameter controls whether the peer
certificate is verified. This allows self-signed certificates to be
properly used with MaxScale.
Only used in conjunction with queued connections, which are not
enabled anyway. Once that comes on the table again, better to use
some standard data structures.
This builds on commit 1287b0e595a5f99026f66df7eeaef091b8ffc774 and cleans
up the original code. This fixes a bug introduced in the aforementioned
commit and cleans up the code.
This commit introduces maxscale::future, maxscale::packaged_task
and maxscale::thread that are modeled after C++11 std::future,
std::packaged_task and std::thread as described here:
http://en.cppreference.com/w/cpp/thread
The standard classes rely upon rvalue references (and move
constructors) introduced by C++11. As the C++ compilers we must use
are pre-C++11 that feature is obviously not present. The absence of
rvalue references is circumvented by implementing regular copy
constructors and assignment operators as if the arguments were rvalue
references.
In practice the above means that when one of these objects are copied,
the state is _moved_ rendering the copied object in default initialized
state. Some care is needed to ensure that unintended copying does not
occur.
