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.
This is not the optimal way to do error handling but it should solve all
problems that could rise from the multi-threaded model of MaxScale.
By taking a lock at the start of handleError, we'll be able to modify the
dcb error handling flag in a thread-safe manner. This should prevent
double error handling for all DCBs.
JSON does not have a concept of streams and a common way to stream JSON is
to separate each JSON object with a newline. Adding a newline makes it
easier to parse as JSON values do not natively contain newlines.
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.
With the use_sql_variables_in=master option, readwritesplit should route
all user variable modifications and reads with user variables to the
master.
Previously, the modification of user variables was grouped into generic
system variables which caused all modifications to system variables to go
to the master only. The router requires a finer grained distiction between
normal system variable modifications and user variable modifications.
With the improvements to the query classifier, readwritesplit now properly
routes all user variable operations to the master and other system
variable modifications to all servers.
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.
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.
The hangup code was refactored into a common function which should only be
used after the server states have been updated. This will remove erroneus
connections to already failed servers.
The master reference used by the readwritesplit sessions needs to be
reassigned if slave reconnection occurs. This happens because the
reference refers to a certain place in the backend reference array
instead of the actual backend reference and those places are mixed
when the array is sorted.
The error logging is now more detailed and tells why the connection is
being closed. This should help the user figure out what is happening when
write fails and the connection is closed.
Some of the master server status checks didn't check whether the server
was actually running. The macros in server.h should always be used instead
of manually inspecting the server status.
If a readwritesplit session is active, it should never connect to a new
master. This will lead to unexpected results as the session states aren't
consistent.
If an illegal DCB close is done with a backend DCB, it will log the server
where it was connected. This allows us to know whether the DCB was
connected to a master or a slave.
Added more debug assertions to readwritesplit code. The DCBs should never
enter the DCB_STATE_DISCONNECTED.
Removed useless debug log messages. The messages usually just flood the
logs with no use to the developers.
A debug assertion failed due to a NULL buffer but a non-zero packet
length. This was caused by a missing reset of the packet length after
freeing the buffers.
Some error messages were logged at INFO level and some had conditions that
prevent the logging. Removed these restrictions that an error situation is
always logged.
If a master_failure_mode was set to error_on_write, a reconnection to the
old master would happen after the following events:
- Master server fails and the connection is closed
- The master server recovers
- A slave fails and the connection is closed
- A replacement for the slave is searched
If these events took place, the master would be taken back into use with
an inconsistent session state.
Binlog server is already configured: if there is no pending transaction
a new binlog file is created after CHANGE MASTER.
If as START SLAVE is issued replication starts as usuale.
If maxscale is restarted the replication starts using the new created
file.
While configuring binlog server for the first time, master.ini not
existent, the specified MASTER_LOG_FILE is created in the $binlogdir.
If START SLAVE command is not issued the replication can start after
restarting maxscale as the binlog file exists.
When a COM_CHANGE_USER statement was executed, the new user credentials
were copied after the authentication message was sent. This caused the
COM_CHANGE_USER to always succeed the first time as it used the current
credentials. The user credentials would always lag behind by one.
When checksum is in use and there is an error in replication stream
master connection the blr_terminate_master_replication has no effect.
MXS-961: The checksum detection calls
blr_master_delayed_connect(router); and connection is scheduled again.
The fix will break the main loop as soon as the error indicator byte is
seen and no other computation will be done (such as checksum)
The default character set should be copied from the server so that
MaxScale appears to be the same. This fixes problems where utf8mb4
couldn't be taken into use because MaxScale would always send latin1 as
the server charset.
When the readwritesplit can't locate the master server when it's checking
the list of available servers, it logs an error if the original master
reference isn't in a valid state. This error should only be logged if the
server is in use but in an unexpected state.
When the authentication string was decoded from hexadecimal to binary, it
was possible that an out of bounds read was done if the length of the data
was not an even number.
The return values of pcre2_match are now properly handled. A positive
match is a return value which is greater than or equal to zero. This fix
should give a small performance boost to as memory is no longer needlessly
allocated.
The backend reference states should be cleared when a reconnection attempt
is made. Should the creation of a new DCB succeed, the backend should no
longer be closed.
Session command responses with multiple packets could be spread across
multiple, non-contiguous buffers. If a buffer contained a complete packet
and some extra data but it wasn't contiguous, the debug assertion in
gwbuf_clone_portion would fail. With release builds, it would cause
eventual out-of-bounds memory access when the response would be sent to
the client.
When a backend causes an error and it should be sent to the client, the
backend reference was closed but the waiting results state was not
cleared. This caused a debug assertion to be hit.
The active operation counters are now closed every time a backend referece
is taken out of use. This should fix a few debug assertions that were hit
in tests.
The `detect_stale_slave` functionality used to only work when MaxScale had
the knowledge that a master server has existed and that replication was
working at some point in time. This might be a "safe" way to do it in
regards to staleness of the data but in practice it is preferrable to
always allow slave to be used for reads.
This change adds the missing functionality to the monitor by assigning
slave status to all servers which are configured as replication slaves
when no master can be found.
The new member variable that was added to the SERVER should be removed in
2.1 where the server_info offers the same functionalty without "polluting"
the SERVER type.
When a client executes commands which do not return results (for example
inserting BLOB data via the C API), readwritesplit expects a result for
each sent packet. This is a somewhat of a false assumption but it clears
itself out when the session is closed normally. If the session is closed
due to an error, the counter is not decremented.
Each sesssion should only increase the number of active operation on a
server by one operation. By checking that the session is not already
executing an operation before incrementing the active operation count the
runtime operation count will be correct.
