The `global` parameter causes the time window defined by the `time`
parameter to be applied at the instance level instead of the session
level. This means that a write from one connection will cause all other
connections to use the master for a certain period of time.
Using a configurable time window for consistency is not good as it is not
absolute and cannot adjust to how servers behave.
One example that demonstrates this is when a slave is normally lagging
behind by less than a second but some event causes the lag to spike up to
several seconds. In this case the configured time window would no longer
guarantee consistency.
Another reason to avoid a "static" time window is the fact taht it
prevents load balancing in the cases where slaves catch up to the master
within time window. This happens when time is configured to a higher value
to avoid inconsistencies at all costs.
Added a test case that verified the feature works.
Since the user authentication stores a SHA2-512 hash of the password on
disk, caching the hash results in memory speeds up the authentication
process significantly. Storing the password on disk in plain-text form
would also speed it up but this would be quite insecure.
The number of sessions wasn't always incremented but it was always
decremented. This happened primarily when authentication failed. By making
the management of the counters a part of the object lifecycle, this
problem goes away.
Requiring contiguous buffers removes the need to use mxs::Buffer which
also removes the need to check for buffer boundaries.
Converted all the functions used by get_canonical into `static inline` so
that the compiler knows it can inline them. A few of them weren't `static`
which made the calls to the functions unnecessarily expensive.
The backslash was added instead of assigned. Since the value stored at
that position is always a null byte, assignment and addition would result
in the same outcome.
Since most of the time users run MaxScale as the maxscale user, we can
change the ownership of the file when it is being created. This prevents
the need to manually set the permissions after the file is created.
If the user creating the file is root, the ownership change will work but
on the other hand if the user simply has write permission into MaxScale's
files, the ownership change will likely cause an error. This will still be
an improvement as the user will know the file ownership needs to be
changed.
The number of sessions wasn't always incremented but it was always
decremented. This happened primarily when authentication failed. By making
the management of the counters a part of the object lifecycle, this
problem goes away.
Requiring contiguous buffers removes the need to use mxs::Buffer which
also removes the need to check for buffer boundaries.
Converted all the functions used by get_canonical into `static inline` so
that the compiler knows it can inline them. A few of them weren't `static`
which made the calls to the functions unnecessarily expensive.
The backslash was added instead of assigned. Since the value stored at
that position is always a null byte, assignment and addition would result
in the same outcome.
The client count was incremented before authentication was complete, and
should be decremented if it fails. Otherwise service connection limit can
be easily reached.
By printing the stacktrace in one log message, it prevents it from
interleaving with other messages. This happens on busy systems and makes
crash analysis harder.
RENAME TABLE is now fully supported and works as expected. With the fix to
table versioning, the new table name will receive the latest version
number.
The table versions are now stored in memory and are only resolved on
startup. This simplifies things and removes the need to know where the
data is stored as that information is not available to the Rpl class.
This adds preliminary support for renaming tables. There is still a
problem where the table version will always be set to 1 on a rename. This
should not be done and the version should be set to the largest value that
ever was for that table.
When lazy_connect is enabled and the first query is `SET autocommit=0`, a
master connection can be created. If it is, then the m_current_master
pointer must also be updated.
Also fixed the case where a failure to connect to one slave would cause
the connection attempts to stop too early.
TIMESTAMP2, DATETIME2 and TIME2 values with decimal parts are now
correctly converted into their string forms. Previously the decimal part
was ignored but most of the code required to extract it was in place.
The unsigned integers that would previously be interpreted as negative
values are now correctly converted into their corresponding avro
values. Due to a limitation in the Avro file format, 64-bit unsigned
integers cannot be represented in their unsigned form.
Since both the signed and unsigned versions of a 32-bit integer cannot fit
into a single Avro int, the type for these was changed to long. This is a
backwards incompatible change which means files generated with older
versions will not convert unsigned values correctly.
The unsignedness of a column is now retained in the Column type as well as
the JSON schema. This allows correct conversion of unsigned integer types
which will be done in a later commit.
