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.
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.
Both the listeners and servers now support IPv6 addresses.
The namedserverfilter does not yet use the new structures and needs to be
fixed in a following commit.
The resultset of SELECTs that use functions whose result will
always vary or whose result depend upon the user executing the
query should not be cached. The list of functions is the same
as that specified for the query cache of MariaDB:
https://mariadb.com/kb/en/mariadb/query-cache/
If user or system variables are used in a SELECT statement, then
the result will not be cached. That ensures that the wrong result
will not be returned.
maxrows returns empty resultset instead of OK.
The response with coulmndefs is sent then an EOF without flags is added.
Limitations: in case of MULTI_RESULT sets only the first one coulmndefs
is sent with EOF
As before, the cache will be used if there is no ongoing transaction
(includes autocommit being on), or if there is an explicitly read-
only transaction.
In addition, the cache will be used and populated during any other
transaction as long as only pure read statements are executed. After
first non-read statement, the use of the cache is disabled.
The autocommit state is now included in the result returned
from session_trx_is_active(), so it need not be checked separately.
This is preparatory work for MXS-1136 that will change the approach
so that the cache is used and populated in a non readonly transaction
*until* the first non-read statement is encountered.
NullFilter is a filter module that does nothing, except reports
capabilities as defined in the configuration file. It's purpose
is only to make it simple to benchmark the performance impact
various routing capabilities have.
Note that since getCapabilities() currently does *not* take an
instance pointer as parameter, all NullFilter instances will
report the same capabilities, the ones specified for the last
filter to have been loaded.
Removed unused spinlocks from DCBs, sessions and the MySQL protocol
structs. They were used in a context where only one thread has access to
the structure.
Removed unused member variables from DCBs.
For instance, if bob is returned an error because he does not have
the required grants, then if the error were cached, alice would
receive bob's error reply even if she has the required grants.
- snake_case
- member variables prefixed with m_
- static member variables prefixed with s_
- where prefixes are used (z,p,s), the following character
is capitalized
The firewall filter should allow COM_PING and other similar commands to
pass through as they are mainly used to check the status of the backend
server or to display statistics. The COM_PROCESS_KILL is the exception as
it affects the state of the backend server. This is better controlled with
permissions in the server than in the firewall filter.
Commands that require special grants aren't allowed to pass as they are
mainly for maintenance purposes and these should not be done through the
firewall.
Moved some typedefs to router.h and server.h, changed a few
constants to these enums. Renamed some types in config.h to
remove "Gateway".
There are still some functions in the public header which are
only used in core, but they seem to fit the theme of public functions
so were not moved.
The filter used the value of `count` for the `time` parameter.
The `options` parameter used the old-style parsing of the options and the
`match` and `exclude` parameters didn't use config_copy_string.
The filter calculated a time difference which was negative if the filter
was not configured to use time intervals.
Added more info level logging to help determine how the filter behaves.
The query operation not being a select is too strict and not very
precise. Only queries that actually modify data should trigger the adding
of routing hints.
