The maxadmin interface to add servers to objects now allows a maximum of
11 objects to be listed. This will make it simpler to add a server to both
a monitor and a service in one command.
The object names in the dbfwfilter weren't very descriptive and were not
that easy to comprehend. The same goes for function names which had
somewhat cryptic names.
This fix allows the gap detection and the writing of an IGNORABLE event
only if master_event_state == BLR_EVENT_DONE.
Note: The hole is not being created if the event is bigger than 16MB
With the advent of qc_get_field_info, columns can now be matched.
However, there is still some undeterminism caused by the table
information not containing contextual information (exactly where
is the table used).
Further, suppose table X contains the column A and table Y contains
the column B, then given a statement like
SELECT a, b from X, Z;
we cannot know whether a is in X or Z, or b in X or Z, without being
aware of the schema, which we currently are not.
Consequently, as long as MaxScale is not aware of the schema, some
heuristics must be applied. For instance, if exactly one table is
referred to, then we can assume that columns that are not explicitly
qualified are from that table.
The rule tests are currently rather rudimentary and need to be
expanded.
When a connection to the master fails, readwritesplit should always treat
it the same way. Previously, if a connection to the master was lost but it
hadn't lost the master status, the failure would be treated like a slave
server failure.
When a server is created in server_create, it sets the port to the default
of 3306 if no explicit port is defined. The code that called this function
still expected a minimum of three arguments: name, address and port.
When a service is added or removed from a service, a supplementary
configuration file is created. This allows MaxScale to survive restars and
unexpected downtime even if runtime changes to the servers of a service
have been made.
With these changes, it is possible to start MaxScale without any servers,
create servers, add the created servers to services and monitors and
restart Maxscale without losing the runtime configuration changes.
When a server is added to a monitor, an supplementary configuration file
is generated to persist this information. This will allow dynamic
modifications to server lists which will survive restarts and unexpected
downtime.
The monitor will only add new servers to its list of monitored
servers. This prevents duplicate entries in the list and makes it safe to
persist all used servers to the supplementary configuration file instead of only the ones that are not listed in the main configuration.
Servers created at runtime can now be configured to use SSL. The
configuration is only possible if the server is not in use.
The `alter server` command in maxadmin now takes a list of `key=value`
strings. This allows the user to define multiple alter operations with one
command.
The functions allow simple operations on configuration context
objects. This makes it easier to understand what the code does and allows
reuse of the configuration processing code.
The backend references now use a common closing function so that all
variables are reset to proper states. The stored queries weren't always
freed and they would leak memory if left open.
Together with the field names, now qc_get_field_info also returns
field usage information, that is, in what context a field is used.
This allows, for instance, the cache to take action if a a particular
field is selected (SELECT a FROM ...), but not if it is used in a
GROUP BY clause (...GROUP BY a).
This caused a significant modifications of qc_mysqlembedded that
earlier did not walk the parse-tree, but instead looped over of a
list of st_select_lex instances that, the name notwithstanding,
also contain information about other things but SELECTs. The former
approach lost all contextual information, so it was not possible
to know where a particular field was used.
Now the parse tree is walked, which means that the contextual
information is known, and thus the field usage can be updated.
The checks for the server active status are now hidden behind a
macro. This allows for the conditions of the activity to change without
having to alter the code that uses it.
Now that servers use an array for the server name, name truncation can
occur. Although this is nigh impossible, a warning message is a prudent
precaution.
Server creation and allocation are now the same apart from the fact that
allocation only adds the server to the running configuration where as the
creation of a server also persist it to disk.
The server serialization should not be seen through the server.h API. This
allows the serialization method to change without actually having to
change the interfaces.
The MySQL Monitor did not reset the pointer to the root master reference
which would lead to a crash if the master was removed.
When service details were shown, it listed all servers that existed. Only
servers that haven't been removed or destroyed should be shown.
If a server were to be destroyed, it should not show up among
non-destroyed servers. Even though the servers aren't actually destroyed,
it hides unnecessary information from the user.
Previously, negative values were allowed for persistpoolmax and
persistmaxtime. Now they cause an error. Also, monitor_interval
allowed negative (or zero) values, which were then implicitly cast to
unsigned, causing unintended behaviour. Now this causes a warning
and the default value is used.
When a server is created via MaxAdmin, it will be serialized to disk. This
allows created servers to be retained through a restart of MaxScale.
Currently, all serialized objects are stored in one folder and there is no
structure in the created files. In the future, servers could be created
under a `servers` subdirectory so that it is easier to see what was
added. Whether there is a need for this will be seen.
