The hangup and error handlers now have unique messages. Although the
behavior in the handlers is practically the same in both cases, the cause
of the error is not the same.
If a socket error is present, it is added to the error message. If an
error is present, it should clearly show the reason why the TCP socket was
closed.
The is_fake_event boolean helps distinguish fake events from real
ones. This makes figuring out the real source of hangup events easier.
The purpose of a COM_RESET_CONNECTION is to reset the connection
states. This means it should be routed to all servers, the same as all
session state modifying commands.
In CentOS8 some -devel packages are moved to PowerTools repository which
is disabled by default. install_build_depends now checks if this repo
is in the repolist then add enablerepo=PowerTools to the yum command
Installation of Docker is removed from build script because it is done
in the not very reliable way and can fail and cause build failure.
E.g. this installation causes conflict with existing Docker.
By checking whether the users have changed whenever they are reloaded, we
improve the visibility of the user reloading process. Using a checksum
allows us to easily compress the information with acceptable loss of
accuracy. Using a CAS loop prevents duplicate messages without losing any
updates even if multiple user reloads result in different outcomes.
The use of a regular expression allows multiple rewrite rules to be
combined into one. This allows more versatile conversions but, given the
simple nature of regular expressions, also makes accidental changes more
likely.
Addd mxs::pcre2_substitute that is a more C++-friendly version of
mxs_pcre2_substitute to make. This makes string replacement a lot easier
to do when the source and destination are not C strings.
When rewrite_src and rewrite_dest have different lengths, the slave must
use GTID based replication. This removes the need for one-to-one matching
between the slave's relay log and the master's binlog which gets broken
when event lengths are modified due to event rewriting.
The replication events use a redundant format that has both the length of
the event and the position of the next event. The length can be modified
so that the next event position of the previous event and the length of
the curren event can be different. This includes overlap of the events
where the next event position of an event is "inside" the current event.
The next event position must retain its original value as that allows
replication slaves to reconnect with the correct position when file and
position based replication is used. For GTID replication, the slave asks
for the coordinates from the master and uses those.
When a slave receives a heartbeat event from a master, it checks that the
binlog name matches and that the next event position in the event is not
behind the slave's relay log position. These events must be modified to
contain a fake next event position that will never be reached by the
slave. This makes sure that the simple sanity checks never fail even if
we've caused the slave's relay log to be ahead of the master's binlog.
The gwbuf_hexdump_pretty displays the hex contents of the buffer alongside
the human-readable version of it. The text version helps identify parts of
the buffer that contain text which makes protocol data decoding easier.
The parameters allow rudimentary database rewriting in the replication
stream. This is still very limited as the replacement must have the same
length as the original. In theory it could be shorter without causing
problems but making it longer is not easy.
The binlogfilter needs to read results one packet at a time but it needs
resultsets to be collected into a single buffer. This behavior is
guaranteed implicitly when the binlogrouter is used but is not present
when it is used without it. To support the use of the binlogfilter with
readconnroute, the filter must properly declare the capabilities.
causal_reads does not work with servers that update their state via
mechanisms other than the standard replication. In practice this is just
another Galera limitation.
