"
Hinted handoff should not overpower regular flows like READs, WRITEs or
background activities like memtable flushes or compactions.
In order to achieve this put its sending in the STEAMING CPU scheduling
group and its commitlog object into the STREAMING I/O scheduling group.
Fixes#3817
"
* 'hinted_handoff_scheduling_groups-v2' of https://github.com/vladzcloudius/scylla:
db::hints::manager: use "streaming" I/O scheduling class for reads
commitlog::read_log_file(): set the a read I/O priority class explicitly
db::hints::manager: add hints sender to the "streaming" CPU scheduling group
When messaging_service is started we may immediately receive a mutation
from another node (e.g. in the MV update context). If hinted handoff is not
ready to store hints at that point we may fail some of MV updates.
We are going to resolve this by start()ing hints::managers before we
start messaging_service and blocking hints replaying until all relevant
objects are initialized.
Refs #3828
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
Hinting is allowed after "started" before "stopping".
Hints that attempted to be stored outside this time frame are going to
be dropped.
Refs #3828
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
Introduce a multi-bit state field. In this patch it replaces the _stopping
boolean. We are going to add more states in the following patches.
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
The space_watchdog enables or disables hints for the managers
associated with a particular device. We encapsulate this decision
inside the hints::managers by introducing the update_backlog()
function.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
A db::hints::resource_manager manages the resources for one or two
db::hints::managers. Each of these can be using the same or different
devices. The db::hints::space_watchdog periodically checks whether
each manager is within their resource allocation, and if not disables
it.
The watchdog iterates over the managers and accounts for the total
size they are using. This is wrong, since it can account in the same
variable the size consumed by managers using different devices.
We fix this while taking advantage of the fact that on_timer is now
called in the context of a seastar::thread, instead of using future
combinators.
Fixes#3821
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Registering a manager for a new device used
std::unordered_map::emplace(), which may not insert the specified
value if one with the same key has already been added. This could
happen if both managers were using the same device and the fiber
deferred in-between adding them.
Found during code reading. Could cause hints to not be disabled for an
overloaded manager.
Fixes#3822
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Disable the copy and move ctors and assignment operators for both the
hints::manager and the hints::resource_manager.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Make sure that read I/O in the context of HH sending do not overpower I/O
in the context of queries, memtable flushes or compactions.
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
Instead of unfreezing a mutation from the commitlog and then freezing
it again to send, just keep the read frozen mutation.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Instead of using find_column_family() and repeatedly asking for
column_family::schema(), use database::find_schema() instead.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
The moving operation changes a node's token to a new token. It is
supported only when a node has one token. The legacy moving operation is
useful in the early days before the vnode is introduced where a node has
only one token. I don't think it is useful anymore.
In the future, we might support adjusting the number of vnodes to reblance
the token range each node owns.
Removing it simplifies the cluster operation logic and code.
Fixes#3475
Message-Id: <144d3bea4140eda550770b866ec30e961933401d.1533111227.git.asias@scylladb.com>
Require a timeout parameter for storage_proxy::mutate_begin() and
all its callers (all the way to thrift and cql modification_statement
and batch_statement).
This should fix spurious debug-mode test failures, where overcommit
and general debug slowness result in the default timeouts being
exceeded. Since the tests use infinite timeouts, they should not
time out any more.
Tests: unit (release), with an extra patch that aborts
when a non-infinite timeout is detected.
Message-Id: <20180707204424.17116-1-avi@scylladb.com>
Rebalance hints segments that need to be sent among all present shards.
Ensure that after rebalancing the difference between the number of segments
of any two shards is not greater than 1.
Try to minimize the amount of "file rename" operations in order to achieve the needed result.
Note: "Resharding" is a particular case of rebalancing.
Tests: dtest: hintedhandoff_additional_test.py:TestHintedHandoff.hintedhandoff_rebalance_test
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
Reserving 10% of space for hints managers makes sense if the device
is shared with other components (like /data or /commitlog).
But, if hints directory is mounted on a dedicated storage, it makes
sense to reserve much more - 90% was chosen as a sane limit.
Whether storage is 'dedicated' or not is based on a simple check
if given hints directory is a mount point.
Fixes#3516
Signed-off-by: Piotr Sarna <sarna@scylladb.com>
Instead of having one static space limit for all directories,
space_watchdog now keeps a per-device limit, shared among
hints managers residing on the same disks.
References #3516
Signed-off-by: Piotr Sarna <sarna@scylladb.com>
In order to make space_watchdog device-aware, device_id field
is added to hints manager. It's an equivalent of stat.st_dev
and it identifies the disk that contains manager's root directory.
Signed-off-by: Piotr Sarna <sarna@scylladb.com>
In order to distinguish which directories reside on which devices,
get_device_id function is added to resource manager.
Signed-off-by: Piotr Sarna <sarna@scylladb.com>
Previously max_shard_disk_space_size was unconditionally initialized
with the capacity of hints_directory. But, it's likely that
hints_directory doesn't exist at all if hinted handoff is not enabled,
which results in Scylla failing to boot.
So, max_shard_disk_space_size is now initialized with the capacity
of hints_for_views directory, which is always present.
This commit also moves max_shard_disk_space_size to the .cc file
where it belongs - resource_manager.cc.
Tests: unit (release)
Message-Id: <9f7b86b6452af328c05c5c6c55bfad3382e12445.1528977363.git.sarna@scylladb.com>
Now that more than one instance of hints manager can be present
at the same time, registering metrics is moved out of the constructor
to prevent 'registering metrics twice' errors.
Constants related to managing resources are moved to newly created
resource_manager class. Later, this class will be used to manage
(potentially shared) resources of hints managers.
When node is decommissioned/removed it will drain all its hints and all
remote nodes that have hints to it will drain their hints to this node.
What "drain" means? - The node that "drains" hints to a specific
destination will ignore failures and will continue sending hints till the end
of the current segment, erase it and move to the next one till there are
no more segments left.
After all hints are drained the corresponding hints directory is removed.
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
Returning a future with an exception from end_point_manager::stop()
is practically useless because the best the caller can do is to log
it and continue as if it didn't happen because it has other things
to shut down.
Therefore in order to simplify the caller we will log the exception
if it happens and will always return a non-exceptional future.
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
"
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>
