"
Additional extension points.
* Allows wrapping commitlog file io (including hinted handoff).
* Allows system schema modification on boot, allowing extensions
to inject extensions into hardcoded schemas.
Note: to make commitlog file extensions work, we need to both
enforce we can be notified on segment delete, and thus need to
fix the old issue of hard ::unlink call in segment destructor.
Segment delete is therefore moved to a batch routine, run at
intervals/flush. Replay segments and hints are also deleted via
the commitlog object, ensuring an extension is notified (metadata).
Configurable listeneres are now allowed to inject configuration
object into the main config. I.e. a local object can, either
by becoming a "configurable" or manually, add references to
self-describing values that will be parsed from the scylla.yaml
file, effectively extending it.
All these wonderful abstractions courtesy of encryption of course.
But super generalized!
"
* 'calle/commitlog_ext' of github.com:scylladb/seastar-dev:
db::extensions: Allow extensions to modify (system) schemas
db::commitlog: Add commitlog/hints file io extension
db::commitlog: Do segment delete async + force replay delete go via CL
main/init: Change configurable callbacks and calls to allow adding opts
util::config_file: Add "add" config item overload
Refs #2858
Push segement files to be deleted to a pending list, and process at
intervals or flush-requests (or shutdown). Note that we do _not_
indescrimenately do deletes in non-anchored tasks, because we need
to guarantee that finshed segments are fully deleted and gone on CL
shutdown, not to be mistaken for replayables.
Also make sure we delete segments replayed via commitlog call,
so IFF we add metadata processing for CL, we can clear it out.
At the moment, various different subsystems use their different
ideas of what a timeout_clock is. This makes it a bit harder to pass
timeouts between them because although most are actually a lowres_clock,
that is not guaranteed to be the case. As a matter of fact, the timeout
for restricted reads is expressed as nanoseconds, which is not a valid
duration in the lowres_clock.
As a first step towards fixing this, we'll consolidate all of the
existing timeout_clocks in one, now called db::timeout_clock. Other
things that tend to be expressed in terms of that clock--like the fact
that the maximum time_point means no timeout and a semaphore that
wait()s with that resolution are also moved to the common header.
In the upcoming patch we will fix the restricted reader timeouts to
be expressed in terms of the new timeout_clock.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
compiler: gcc (GCC) 6.3.1 20161221 (Red Hat 6.3.1-1)
Problems introduced in f6a461c7a4
and 37b19ae6ba, respectively.
They both fail to compile due to use of method in lambda without
explicit mention of this. Some of failure is fixed by not using
auto in lambda parameter.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20171218222144.12297-1-raphaelsc@scylladb.com>
