Due to the skewed accept distribution without SO_REUSEPORT, we use
round-robin assignment of workers for new client connections. This
provides better performance as work is more likely to be evenly
distributed across all threads.
Using a least-busy-worker algorithm would provide a more stable result but
this is not trivially simple to implement. For this reason, the
round-robin based approach was chosen for 2.2.
Parameters that accept whitespace-only values need to have their default
values quoted if they contain only whitespace characters. In 2.2 the
qlafilter is the only module that did not do this.
When a test is checking the status of the nodes, the output is relatively
verbose.
Also changed dropping of users to use the IF EXISTS syntax. This will
remove the errors if the users do not exist.
When a valid target was not found, no error message was logged by the
router. This would cause the "Routing the query failed. Session will be
closed." message to be logged with no explanation as to why the routing
failed.
In addition to the above-mentioned case, no message would be logged if the
target for a COM_STMT_FETCH was not in use.
If the authentication failure was due to a missing database, this extra
information can be logged. This will help cases where users are using
databases that do not exist.
If only one server is used, the amount of requests can be reduced from a
minimum of two to a minimum of one. In most cases this cuts down the
response time in half.
Also change the following defaults:
- "selects": Was "verify_cacheable", is now "assume_cacheable"
- "cached_data": Was "shared", is now "thread_specific"
Don't test failover functionality when it is not needed. The bug is only
about the extra events that appear when a master is demoted and a slave is
promoted.
Prepared statements via readwritesplit need to have their IDs mapped from
the internal representation to the backend specific one. The RWBackend
class does this in its write method but the fix in commit
e561c3995c7396cf3749ccdf6a3357d7dd32c856 caused this to be bypassed and
the base version was always used.
If a session command produces a different result on the slave than it did
on the master, a warning is logged. This warning now also logs the query
that was being executed to make investigation of the problem easier.
Backend::execute_session_command would use the overridden write method
instead of the Backend::write method that it intended to use. This caused
session commands that did not expect a response to be in a state that
expected a result.
Also fixed RWBackend::write pass the response_type value to
Backend::write.
Going the belt-and-suspenders way of both sleeping and waiting for the
moitor should make sure MaxScale has at least some time to start up, query
the servers and do a single iteration of monitoring.
If the service user does not have adequate grants to the mysql tables, the
legacy query is used. This prevents an upgrade failure when the user was
lacking the new privileges.
The user now requires SELECT privileges on the mysql.roles_mapping
table.
Currently this is a mandatory grant but it needs to be made into an
optional requirement. This allows upgrades from 2.2.9 to 2.2.10 without
needing new grants.
The cache filter walks through the resultset in order to detect
when the resultset ends. That is, it reads each packet header as
they arrive.
In case the resultset is large, the cache will have to read several
packet headers. That it does using gwbuf_copy_data(). However, as that
was done using the first received GWBUF as the starting point, it meant
that in gwbuf_copy_data() the buffer chain was walked over and over
and over again, with a significant performance hit as the result.
Now we separetely store the last buffer received, and the the starting
offset of it. That way there will be no buffer chain walking.
As this is a common problem, GWBUF could cache the offset of the tail,
thus removing the performance penalty if you read from an offset that
happens to be in the tail. However, it's better to do that as a part
of a general overhaul of GWBUF.
If the server sends a server shutdown error, it is safe for readwritesplit
to ignore it. When the TCP connection is closed, the router error handling
will discard the connection, optionally replacing it.
The function implemented redundant functionality and replacement with
modutil_get_next_MySQL_packet was planned.
When faced with a packet header spread over multiple buffers, the packet
length calculation would read past the buffer end. This is fixed by taking
modutil_get_next_MySQL_packet into use.
Identical behavior to the old function is achieved by calling
gwbuf_make_contiguous for each packet to store them in a contiguous area
of memory. This should be either removed and only done when
RCAP_TYPE_CONTIGUOUS_INPUT is requested or be made an innate feature of
statement based routing.
The test unnecessarily did an unconditional drop of the user resulting in
errors. Also prevented stopping of MaxScale if it wasn't started in the
first place.
The debug assertion introduced by commit 3d1c2b421a fails when a
COM_CHANGE_USER was executed. This was caused by the fact that the
authentication data was being interpreted as a command when it should've
been ignored.
Added a debug assertion into the reauthentication code to make sure the
current command remains the same.
