The readwritesplit now sends COM_PING queries to backend servers that have
been idle for too long. The option is configured with the
`connection_keepalive` parameter.
It is now possible to specify what information the caller is interested
in. With this the cost for collecting information during the query parsing
that nobody is interested in can be avoided.
The match data needs to be unique for each thread, so for the time
being it is created whenever it is needed. A more performant (although
possibly to a negigible amount) solution would be to have a separate
match data for each thread, but that will have to wait for 2.2.
When MaxScale is being started and the users are loaded, the MySQL
authenticator should not load the database users for internal services
abstracted as servers.
The loading of users at startup for internal services is avoided because
the startup is done in a single thread context and the internal services
have not yet been started.
The delayed loading of users will cause the authentication to fail when
the first client connect. This triggers the reloading of the users and the
second attempt at authentication will succeed. All of this is hidden from
the end user.
If a server points to a local MaxScale listener, the permission checks for
that server are skipped. This allows permission checks to be used with a
mix of external servers and internal services.
The static module capabilities are now used to query the capabilities of
filters and routers. The new RCAP_TYPE_NOAUTH capability is also taken
into use. These changes removes the need for the `is_internal_service`
function.
The static capabilities declared in getCapabilities allows certain
capabilities to be queried before instances are created. The intended use
of this capability is to remove the need for the `is_internal_service`
function.
The filter now checks what types of parameters it has been given and
only accepts the old style (match, server) XOR new style (match01,
target01 etc).
Adds support for special targets ->master and ->slave.
Code cleanup.
- Selects are picked out using custom parsing, so if a statement is
anything else but a SELECT, the cache will never cause the statement
to be parsed.
- The setting of of the cache parameter `selects` is taken into account.
If it is `assume_cacheable` then the statement will also not be parsed
even if it is a SELECT.
The server state information should be persisted even if a controlled
shutdown is done. This will allow the monitor to retain the server state
information across a restart.
The MySQL monitor stores the server states in a backup file which can be
used to restore the state of the servers even if MaxScale is stoppen in an
uncontrolled fashion.
The hintrouter is now in principle capable of routing requests
to the master or to some slave (in a round robin fashion) based
upon hints set by some earlier filter.
Note that as the router is completely oblivious of transaction
boundaries, using it with transactions and autocommit being off
will not make anyone happy.
Recognizing transaction boundaries using regexes and then pinning
the server until transaction commit would be needed.
The original approach was made for RocksDB where it is beneficial
to keep keys of stuff related to each other close to each other.
However, as RocksDB is no longer the primary focus, it just causes
additional cost to dig out the table names.
The key is a 64-bit integer, but crc32 only gives us a 32-bit one.
We create an other 32-bit value by running crc32 over the same SQL,
using the first crc value as adler.
I think that further reduces the chance for clashes:
uint32_t crc0 = crc32(0, Z_NULL, 0);
uint32_t crc1;
uint32_t crc2;
crc1 = crc32(crc0, "codding", 7) => 1774765869
crc2 = crc32(crc1, "codding", 7) => 1409592046
crc1 = crc32(crc0, "gnu", 3) => 1774765869
crc2 = crc32(crc1, "gnu", 3) => 1213798908
Note that the first value is the same, but the second is not.
When a standalone master server is detected, it should receive the stale
status to prevent it from losing the master status if another server is
started and allow_cluster_recovery is enabled.
The json_stringn function should be used instead of the json_string to
allow null characters as well as non-null terminated strings to be
embedded in the JSON values.
The CDC example Python programs now decode the data as UTF-8 instead of
ASCII.
Move most of the functions under the filter or session-classes.
Class definitions moved to a header file. General cleanup. Some features
are still incoming.
The filter now accepts (in addition to the old "match" and "server")
parameters of the form "matchN" and "serverN", where N is a decimal
number with two digits, i.e 01, 02, 03 .. 20. When routing queries,
the regural expressions will be tested one by one, and the servers
from the first match will be added as hints. Also, a single "server"-
setting may contain multiple servers separated by ','. The server
names are not verified to be actual servers, this is up to the user.
Transaction boundaries can now be detected using regexes.
All else being equal, it gives a 10% performance improvement
compared to qc-based detection.
In a subsequent change, mysql_client.c will be modified to use
qc_get_trx_type_mask() instead of qc_get_type_mask().
Currently the use of regex matching is turned on using an
environment variable. That will change.
The process and thread initialization/finalization of the query
classifier plugins is handled using the process and thread
initialization/finalization functions in the module object.
However, the top-level query classifier will also need to perform
process and thread initialization when transaction boundaries are
detected using regular expressions.
The connector plugin directory can now be controlled with the
`connector_plugindir` argument and configuration option. This should allow
the connector to use the system plugins if the versions are binary
compatible.
Replaced calls to mysql_options to mysql_optionsv as the former is
deprecated in Connector-C 3.0 and the latter is supported in Connector-C
2.3.
The core now provides a simple function to close a session. This removes
the need for the modules to directly call the API entry points when the
session should be closed. It is also in line with the style that other
objects, namely the DCBs, use. This makes the new session_close very
similar to dcb_close.
The client protocol module can resolve whether a password was used based
on the information the authenticators gather before authentication is
done. It uses the authentication token length as the basis on which it
makes the decision.
The users were deleted before each individual server was queried. This
caused authentication to fail if the authentication data was loaded from
multiple servers.
The client connection and the server listener sockets used largely similar
code. Combining them allows for simpler protocol code.
Cleaned up parts of the DCB listener creation and moved the parsing of the
network binding configuration to a higher level.
