Deep-copying prevents subsequent modifications done by the caller from
affecting the data that can be potentially stored in the write queue of
the backend's DCB.
It was possible that a one-second outage that caused immediate rejection
of network connections would cause all of the query retry attempts to fail
within a very short period of time. By preventing rapid reconnections,
query_retries is more effective as an error filtering mechanism.
Centos6 uses a very old version of SQLite without support for URI filenames.
PAM authenticator must use a file-based database.
Commit cherry-picked to 2.4.0 from 2.3.
If a COM_STMT_EXECUTE has no metadata in it and it has more than one
parameter, it must be routed to the same backend where the previous
COM_STMT_EXECUTE with the same ID was routed to. This prevents MDEV-19811
that is triggered by MaxScale routing the queries to different backends.
mxs::Buffer::iterator is not a random-access iterator and hence will have
linear cost. This is too costly to do on every packet with even moderately
sized resultsets.
Due to there being no distinction between a temporarily stopped worker and
a permanently stopped one, we must allow posting of messages to stopped
workers.
By always restoring the ID, we are guaranteed to only store the query in
the form that it was originally sent in. This should be changed so that
the ID that the client sends can be used as-is in the backends.
By having a separate FINISHED state and a STOPPED state, it is possible to
know at which point in the worker's lifetime an event is done. Posting of
messages before a worker is started is allowed but posting them after the
worker has stopped is not.
This fixes avrorouter related failures and all other failures that stem
from worker messages being ignored at startup.
