The query throttling functionality was broken by the move to the per
thread rule system. One way to fix this is to move the session specific
throttling information into the client session itself. This allows for a
simpler system with no direct dependencies on the rules or users
themselves.
The modulecmd functionality allows the avrorouter to easily control the
conversion process with one command. The conversion can now be started and
stopped by the user.
This also fixes a bug where the conversion would stop if there were no
binlog files present when the service was started.
MXS-1009. This commit adds a gwbuf_free after maxinfo_execute() to
free a buffer with an sql-query after it has been processed. Also,
the parse tree in maxinfo_execute_query() is now freed. The tree_free-
function was renamed to maxinfo_tree_free, since it is now globally
available.
This commit has additional changes (in relation to the 1.4.4 branch)
to remove errors caused by differences in the html and sql-sides of
MaxInfo.
Storage is now abstract with StorageReal (that uses an actual
storage module) derived from it. This to prepare for a stackable
case where LRU behaviour is implemented in front of the actual
physcal storage.
The per thread cache is implemented so that there is one single
thread cache per thread.
This uses shared_ptr, which is available in different places
depending on which GCC version is default on the target platform.
So, before this is merged to develop, that needs to be sorted out.
A simple cache is one that does not transparently use multiple
storages in the background. That will be the case when a separate
cache per thread is used. Both CacheST and CacheMT are now derived
from CacheSimple.
A fair amount of what used to be in Cache has now been moved to
CacheSimple. What remains is what surely is common for all cache
types.
The service header in include/maxscale/ contains the public part of the
service API. These functions can be safely used by the modules.
The internal header located in service/core/maxscale/ is used by the core
to initialize MaxScale at startup or to provide other services in a more
controlled way (the config_runtime, for example).
The listeners aren't really destroyed and are only stopped. Further
changes are required so that they won't be started again once they have
been destroyed.
Now the basic structure is in place:
- cachefilter.cc is the MaxScale filter interface.
- Cache is the actual cache class that will also handle LRU issues.
- SessionCache (sessioncache.cc) is the session specific cache class
that using Cache acts as the cache for a particular session.
If an item is stale, then one SessionCache will update it.
- StorageFactory is the component that is capable of loading a module
providing storage facilities.
- Storage is the actual key/value store.
The storage module is abstracted with StorageFactory that is capable
of creating Storage instances. The latter contains the data and
provides the behaviour for using the actual storage implementation,
which sits behing a C API, conveniently.
The server test used the wrong name.
MySQL users test loaded multiple modules in one function call and wasn't
appropriate for an internal test suite test as it requires a working
installation.
The cache filter didn't set the library paths before trying to load
modules.
The binlogrouter was missing a NULL check which caused a crash.
Maxadmin now supports the runtime creation of listeners. The new 'default'
value can be used to signal values that don't need to be configured and
the default value should be used.
The config_runtime.h header contains functions that can be used to
manipulate the running configuration. Currently the header contains the
function to create, add, remove and destroy servers.
If an item cannot be put to the database, it is explicitly removed
to ensure that we cannot have the situation that a stale item is
continuously returned because the updating of the value fails for
whatever reason.
If a cached entry becomes stale, then if no extra measures are
taken then every thread hitting that item while it is being fetched
from the server will also refresh it, even though it obviously is
sufficient that one does it.
Now the knowledge that the item is being refreshed is recorded,
so that all other clients are simply returned the stale item. That
way, we'll hit the server once per stale item.
The rules and users are stored in thread-local pointers which removes the
need to hold global locks. This allows greater scalability but causes a
slightly larger memory footprint. Usually the increase in memory
consumption is trivial compared to the benefits in scaling.
Using a per-thread rule and user list allows changes to be applied
immediately without locking on the instance level.
The updating of the rules uses the new functinality described in the
debugcmd.h header. The module registers two functions at startup; one for
reloading rules and one for printing them. These custom functions can be
seen in the `maxadmin list functions` output.
The packet was generated with the wrong number of elements due to usage of
sizeof on an integer where the correct type was an uint8_t.
This only fixes the malformed packets but does not fix the root cause of
the problem. The affected rows and last insert ID are length encoded
integers which should be handled. The current code treats them as one byte
fields.
Since it's a cache, we do not need to retain the data from one
MaxScale invocation to the next. Consequently, we can turn off
write ahead logging completely if we simply wipe the RocksDB
database at each startup. In addition, the location of the
cache directory can now be specified explicitly, so it can be
placed, for instance, on a RAM disk.
The prepared statements were router according to the real type instead of
being router to the master. This was caused by the change in the route
target function.
This commit adds a free() to null_auth_free_client_data, which plugs
the memory leak in maxinfo.
Also, this commit fixes some segfaults when multiple threads are
running status_row() or variable_row(). The functions use
statically allocated index variables, which often go out-of-bounds
in concurrent use. This fix changes the indexes to thread-specific
variables, with allocating and deallocating. This does seem to slow
the functions down somewhat.
