MXS-1412: while discarding a result set don't buffer any data: this
avoids to store useless data.
Additionally the colum definitions buffer is used instead of the offset
value.
By processing each buffer individually, the need to iterate over the whole
resultset is removed. Profiling showed that most of the time was spent
navigating the linked list of buffers when an offset into the whole
resultset was used instead of an offset to the individual response buffer.
When a COM_CHANGE_USER was executed, it is possible that the server
responds with a AuthSwitchRequest packet instead of an OK packet. In this
case, the server sends a new scramble which must be used to create the 20
byte hash that is expected as the response.
The COM_CHANGE_USER that is sent as a part of the reset process for a
persistent connection did not expect a AuthSwitchRequest packet to be sent
as that implies that the server did not take the authentication fast
path. In this case, an error message needs to be logged stating that the
server requested a different authentication plugin than was expected.
The response handling logic did not always take the last packet for
inspection when a COM_CHANGE_USER was executed. The OK packet will always
be the last one since the COM_CHANGE_USER is the last command that was
sent.
When an unexpected response to a COM_CHANGE_USER is received, it is now
processes and discarded instead of treated as an error. This will allow
further analysis of the situation in addition to possibly solving some of
the problems that the persistent connections have.
Added extra info level logging to relevant parts of the code that deal
with the COM_CHANGE_USER reply processing. This information should allow
tracking of the response state for debugging purposes.
The response to the COM_CHANGE_USER should always be turned into a
contiguous buffer of complete packets. This guarantees that the code that
processes it functions properly.
As COM_QUIT would terminate the connection, there's no need to initiate
the session reset process. Also make sure all buffers are empty before
putting the DCB into the pool.
Added extra debug assertions for parts of the code that are related to the
COM_CHANGE_USER processing.
When a persistent connection is reused, a COM_CHANGE_USER command is
executed to reset the session state. If the reused connection was closed
before the response to the COM_CHANGE_USER was received and taken into use
by another connection, another COM_CHANGE_USER would be sent to, again,
reset the session state. Due to the fact that the first response is still
on its way, it will appear as if two responses are generated for a single
COM_CHANGE_USER.
The way to fix this is to avoid putting connections that haven't been
successfully reset into the connection pool.
When a session is being closed in a controlled manner, i.e. a COM_QUIT is
received from the client, it is possible to deduce from this fact that the
backend connections are very likely to be idle. This can be used as an
additional qualification that must be met by all connections before they
can be candidates for connection pooling.
This assumption will not hold with batched and asynchronous queries. In
this case it is possible that the COM_QUIT is received from the client
before even the first result from the backend is read. For this to work,
the protocol module would need to track the number and state of expected
responses.
If the binlog has binlog checksums enabled, the extra checksum bytes are
removed from the end of the event. The avrorouter assumes that whatever
caused the binlogs to appear in the first place already checked that the
checksums are OK.
Also removed one extra byte being added to the length of all query events.
A new option ‘slave_hostname’ allows the setting of hostname in
COM_REGISTER_SLAVE.
SHOW SLAVES HOSTS; in master server can show the hostname set in binlog
router:
MariaDB [(none)]> SHOW SLAVE HOSTS;
+-----------+-----------------------------+------+-----------+
| Server_id | Host | Port | Master_id |
+-----------+-----------------------------+------+-----------+
| 93 | maxscale-blr-1.mydomain.net | 8808 | 10124 |
+-----------+-----------------------------+------+-----------+
If a connection has not been fully established (i.e. authentication has
been completed) then it should not be considered as a connection pool
candidate.
Enabling the option hinders the use of maintenance mode with the root
master node in most use-cases.
This behavior occurs due to the fact that the maintenance mode causes a
server to be treted as if it was down. The Galera monitor waits for the
cluster to reorganize before assigning a new master node. This is correct
(but very unexpected) behavior for single instance use-cases.
The query classifier should only be used to parse text protocol
statements. The insertstream filter exploited the fact that any statements
that the filter did not expect would be classified as an unknown
commands. This led to repetitive error messages with binary protocol
statements.
When a backend is waiting for a response but no statement is stored for
the session, the buffer where the stored statement is copied is not
modified. This means that it needs to be initialized to a NULL value.
Added a test that checks that the behavior works as expected even with
persistent connections. A second test reproduces the crash by executing
parallel SET commands while slaves are blocked.
There is still a behavioral problem in readwritesplit. If a session
command is being executed and it fails on a slave, an error is sent to the
client. In this case it would not be necessary to close the session if the
master is still alive.
The asserted value can be false without it being an error. When a table is
re-mapped to a different position, there is no guarantee that the previous
value has not been reused by another table.
If a rule is defined with only an optional part, it should be of the
permission type. This type is used to signal that the rule matches if the
optional constraints are fulfilled.
Due to refactoring, the default type was changed from RT_PERMISSION to
RT_UNDEFINED.
The schemarouter can now resolve database mapping conflicts in a
deterministic manner. This will fix the problem of central databases which
are replicated shards being assigned in a non-deterministic manner.
When the current database is implicitly used in a query that also uses an
explicit database, it must be routed to the shard which has the current
database.
As cross-shard joins are not supported, the safest, and possibly the most
expected course of action to take, is to route it to the so-called default
shard. The default shard is the shard that contains the database that is
currently set as the active database with a COM_INIT_DB, a text protocol
USE <database> query or it was set at connection time.
The avrorouter failed to detect ALTER TABLE statements which caused a
regression. Extended the alter table tests to parse the JSON for more
strict validation of test results.
The multimaster node detection uses stacks to sort the node groups. The
size of this stack was always assumed to be positive but it was possible
that it dropped down to -1 causing a crash when the stack was accessed
with the index number.
The EVP_CIPHER_CTX is now created inside a wrapper function to add support
for OpenSSL 1.1. Also fixed improper use of the EVP_CIPHER_CTX internals
in binlogrouter.
There's no need to use Python 3 for the script and using it introduces
problems due to the poor availability of MySQL Connector/Python for
Python3.
ENUM, SET and DECIMAL values should have a length of -1 as the length is
meaningless for these types.
The HintParser wrongly ignored linebreaks, causing parsing faults
e.g. parsing too far or accepting invalid comments. Now, the parser
detects a line break and terminates comments unless they started with
'/*'. Also, fixed a memory leak when parsing parameter-value-combinations.
Whenever a server which is a slave of an external master is detected, it
will be assigned the slave status. This will allow the status to be used
the way it was intended to be used.
The modutil_get_SQL()-function allocates storage, while
modutil_extract_SQL() does not. The strings given by the latter
are not 0-terminated so require a length limit when matched using
regexec().
This commit changes the used function in those cases where the
sql-string is not modified nor is the pointer saved for later use.
