With this variables set to true, if $VAR is used as a value in the
configuration file, then `$VAR` will be replaced with the value of
the environment variable VAR.
When binary data was processed, it was possible that the values were
misinterpreted as OK packets which caused debug assertions to trigger.
In addition to this, readwritesplit did not handle the case when all
packets were routed individually.
If multiple queries that only generate OK packets were executed, the
result returned by the server would consist of a chain of OK packets. This
special case needs to be handled by the modutil_count_signal_packets.
The current implementation is very ugly as it simulates a result with at
least one resultset in it. A better implementation would hide it behind a
simple boolean return value and an internal state object.
A multi-statements can return multiple resultsets in one response. To
accommodate for this, both the readwritesplit and modutil code must be
altered.
By ignoring complete resultsets in readwritesplit, the code can deduce
whether a result is complete or not.
The original offset needs to be separately tracked to assert that an OK
packet is not the first packet in the buffer. The functional offset into
the buffer is modified to reduce the need to iterate over buffers that
have already been processed.
Returning the results of a query as a set of packets is currently more
efficient. This is mainly due to the fact that each individual packet for
single packet routing is allocated from the heap which causes a
significant loss in performance.
Took the new capability into use in readwritesplit and modified the
reply_is_complete function to work with non-contiguous results.
The GLIBC backtrace functionality doesn't generate file names and line
numbers in the generated stacktrace. This can to be done manually by
executing a set of system commands.
Conceptually doing non-signal-safe operations in a signal handler is very
wrong but as stacktraces are only printed when something has gone horribly
wrong, there is no real need to worry about making things worse.
As a safeguard for fatal errors while the stacktrace is being generated,
it is first dumped into the standard error output of the process. This
will function even if malloc is corrupted.
The GWBUF shared buffer and its data is now allocated in one
chunk so that the data directly follows the shared buffer.
That way, creating a GWBUF will involve 2 and not 3 calls to
malloc and freeing one will involve 2 and not 3 calls to free.
Inlined the getter/setter type functions that are often used. Profiling
shows that inlining the RWBackend get/set functions for the reply state
manipulation reduces the relative cost of the function to acceptable
levels. Inlining the Backend state function did not have as large an
effect but it appears contribute a slight performance boost.
KILL commands are now sent to the backends in an asynchronous manner. As
the LocalClient class is used to connect to the servers, this will cause
an extra connection to be created on top of the original connections
created by the session.
If the user does not have the permissions to execute the KILL, the error
message is currently lost. This could be solved by adding a "result
handler" into the LocalClient class which is called with the result.
The total timeout for the retrying of interrupted queries can now be
configured with the `query_retry_timeout` parameter. It controls the total
timeout in seconds that the query can take.
The actual connection, read and write timeouts of the connector aren't a
good configuration value to use for abstracted queries as the time that it
takes to execute a query can be composed of both connections, reads and
writes. This is caused by the usage of MYSQL_OPT_RECONNECT that hides the
fact that the connector reconnects to the server when a query is
attempted.
The new `query_retries` parameter controls how many times an interrupted
query is retried. This retrying of interrupted queries will reduce the
rate of false positives that MaxScale monitors detect.
The stack traces weren't logged as the LOG_ALERT priority wasn't enabled
by default. As an alert is intended to be something that must leave a
trace somewhere, and as such, it must not be possible to disable it. For
this reason, it is acceptable to always log the message if the priority is
LOG_ALERT.
Added the -rdynamic linker flag so that all symbols are exported when
linking MaxScale.
As the stack trace is printed in a signal handler, the first attempt
should be to print the stack trace to the standard output. This way the
output is printed before an attempt to use malloc is made when it is
logged to the logfile.
If a module command returns a json object, it will always be
returned to the caller, irrespective of whether the command
itself succeeded or not.
Otherwise, if the command failed and if the module command has
set an error message, that error message will be returned as a
json object containing the error message.
Since the module command interface was expanded to include a JSON output
parameter, there is no longer a need for an output DCB. As the JSON can be
printed by both maxadmin and the REST API, this allows the removal of
explicit output formatting in module commands.
The `script_timeout` and `journal_max_age` parameters weren't handled in
the monitor alteration code.
Also added missing documentation to maxadmin help output for
`alter monitor`.
If a script variable resolves to an empty string, the replacement attempt
will fail with an out-of-memory error. The following realloc call will
fail as it requires a positive value for the new size.
The CHILDREN parameter expands to a list of server IPs and ports that are
direct descendants of the server that initiated the event.
Also added a note that the variables can expand to empty strings if
nothing matches the criteria of the variable.
The scripts now replace the PARENT variable with the IP and port of the
server that is the direct parent node of the server that initiated the
event. For master-slave clusters, this will be the master IP if the server
that triggered the event is a slave.
If the executed subprocess prefixes its output with either `error:`,
`warning:` or `info:`, the message will be logged on the appropriate
level. If no prefix is provided, the message is logged on the notice
level.
When the subprocess outputs a line, the message should be logged
immediately. This allows automated timestamps for the output of the
executed subprocess.
By moving the initialization into Worker::run, all threads, including the
main thread, are properly initialized. This was not noticed before as
qc_sqlite initialized the main thread in the process initialization
callback.
The enums exposed by the connector are not intended to be used by the
users of the library. The fact that the protocol, and other, modules used
it was in violation of how the library is intended to be used.
Adding an internal mapping into MaxScale also removes some of the
dependencies that the core has on the connector.
Cleaned up the MaxScale version of the mysql.h header by removing all
unused includes. This revealed a large amount of dependencies on these
removed includes in other files which needed to be fixed.
Also sorted all includes in changed files by type and alphabetical
order. Removed explicit revision history from modified files.
