When MaxScale is started, it will attempt to create the PID directory. If
the directory does not exist and MaxScale is able to create it, MaxScale
will successfully start whereas it previously failed to do so.
If MaxScale lacks the permissions to create the directory, an error
message is printed to the user explaining the reason why MaxScale fails to
start.
The resultset of SELECTs that use functions whose result will
always vary or whose result depend upon the user executing the
query should not be cached. The list of functions is the same
as that specified for the query cache of MariaDB:
https://mariadb.com/kb/en/mariadb/query-cache/
If user or system variables are used in a SELECT statement, then
the result will not be cached. That ensures that the wrong result
will not be returned.
If all but one server in a cluster fail and `failover` is enabled for
mysqlmon, the last server would be used as if it were a master. With this
change, the restrictions on failover also require that the last server is
not configured as a slave.
This change will prevent unintended failovers from happening when network
connectivity is bad. It also allows external actors to clear the slave
configuration from the last remaining server to signal MaxScale that the
server can be used as a master.
maxrows returns empty resultset instead of OK.
The response with coulmndefs is sent then an EOF without flags is added.
Limitations: in case of MULTI_RESULT sets only the first one coulmndefs
is sent with EOF
As before, the cache will be used if there is no ongoing transaction
(includes autocommit being on), or if there is an explicitly read-
only transaction.
In addition, the cache will be used and populated during any other
transaction as long as only pure read statements are executed. After
first non-read statement, the use of the cache is disabled.
The autocommit state is now included in the result returned
from session_trx_is_active(), so it need not be checked separately.
This is preparatory work for MXS-1136 that will change the approach
so that the cache is used and populated in a non readonly transaction
*until* the first non-read statement is encountered.
The thread id is copied to a local variable to avoid having
__tls_get_addr from unnecessarily being called over and over
again. Together that used to amount to some 1% of the execution
time.
Altered the function to assert that the DCB is a backend DCB in addition
to the existing assertions for non-NULL backend reference on function
return.
Move the fetching of the backend reference after the type of the DCB is
inspected in handleError. This removes the need to handle the case where
the returned bref is NULL and the DCB is a client DCB.
They are not particularly useful, they surely are not used
and impose a small cost for every event extracted from the
poll sets.
This commit only removes the maxadmin commands, subsequent
commits will remove the actual code.
These fixes prevent loops turning into eternal loops when
optimizations have been turned on.
The right remedy is to remove the internal locks from hashtable
and use external locks instead.
Due to the changes in the threading model, the DCB write code can be
simplified by a great amount.
Since only one thread can write to a DCB, it's safe to assume that no new
data is added to the write queue of a DCB while it is being drained. This
removes the need for the code that tracks whether a concurrent DCB write
attempt was made.
Because the high and low water callbacks weren't used by any module, it is
safe to remove them. They offer no real benefits over the drain callback.
The highwater and lowwater callbacks were never registered for the client
DCBs in the binlogrouter.
The DCB hangup callbacks were never called by the core and were replaced
with fake hangup events in an earlier version.
Maxavro now supports reading records with the zlib deflate
algorithm.
With this change, each data block is read into memory in one IO
operation. This allows the library to decompress the data block if
necessary.
The avrorouter does not yet use compression when writing the records.
The `failover_recovery` option allows failed servers to rejoin the
cluster. This should make using MaxScale with two node clusters easier.
One use case for this is when the replication-manager promotes the last
node in the cluster as the master. When this is done, the slave
configuration is cleared and the read-only mode is disabled. Since the
failover requires that the server is not configured as a slave and that it
is not in read-only mode, it is safe to use `failover_recovery` with
replication-manager.
maxbinlogcheck with new -T $pos option can find the BEGIN of
transaction where $pos belongs to and then replace all events in
between with IGNORABLE events
