Make sure to close the builder's _updates and optional _existings
readers before they are destroyed.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
If reader.fill_buffer() fails, we will not call `maybe_pause` and the
reader will be destroyed, so make sure to close it.
Otherwise, the reader is std:move'ed to `maybe_pause` that either
paused using register_inactive_read or further std::move'ed to _reader,
in both cases it doesn't need to be closed. `with_closeable`
can safely try to close the moved-from reader and do nothing in this
case, as the f_m_r::impl was already moved away.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Close the _closing_gate to wait on background
close of dropped queries, and close all remaining queriers.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Make sure to close the dropped querier before it's destroyed.
The operation is moved to the background so not to penelize
the common path.
A following patch will add a querier_cache::close() method
that will close _closing_gate to wait on the querier close
(among other things it needs to wait on :)).
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
In preparation to closing the querier in the background
before dropping it.
With that, stats need not be passed as a parameter,
but rather the _stats member can be used directly.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Make sure to close the querier and subsequently its reader before
destroying it (unless it was moved).
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Depening on the variant _reader contents, either close
the reader or unregister the inactive reader and close it.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Instead of calling a lambda function for each index
simply iterate over all indices and use co_await / co_return
in the inner loop.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Make sure to close the unregistered inactive_read
before it's destroyed, if the unregistered reader_opt
is engaged.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
"forward" the unregister to the other semaphore
in case on_internal_error throws rather than aborting.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Close readers in the background:
- evicted based on ttl, or
- those that weren't admitted by register_inactive_read
- those that are destoryed in clear_inactive_reads.
Use a gate for waiting on these background closes in stop().
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
enqueue_waiter before evicting readers and start a loop in the
background to dequeue and close inactive_readers until
either the _wait_list is empty or there are no more inactive_readers
to evict.
We admit the read synchronously only if the wait_list is empty
and the semaphore has_available_units to statisfy admission.
We need to enqueue the reader before starting to evict readers
to make sure any evicted resources are assigned to the
waiter at the head of the queue and not "stolen"
in case we yield and some other caller grabs them.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
In addition to clear_inactive_reads, that's currently called when
the database object is destroyed, introduce a stop() method that will:
1. wait on all background closes of inactive_reads.
2. close all present inactive_reads and waits on their close.
3. signal waiters on the wait_list via broken() with a proper
exception indicating that the semaphore was closed.
In addition, assert in the semaphore's destructor
that it has no remaining inactive reads.
Stop must be called from whoever owns the r_c_s.
Mainly, from database::stop.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Rather than explcitily generating it by all callers
and then not using the argument at all.
Prepare for providing a different exception_ptr
from a stop() path to be introduced in the next patch.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Currently unregister_inactive_read for other shards is moved
to the background with nothing keep the respective
reader_concurrency_semaphore around.
This change runs the loop in parallel_for_each
so that we don't have to serially wait on all of them
but rather they can run in parallel on all shards, but
all are waited on via the returned future<>.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Currently only if the reader_meta is in the saved state
we unregister its inactive_read, yet it is possible
that it will hold an inactive_read also in the lookup state.
To cover all cases, rather than testing the reader_state,
unregister if the inactive_read_handle is engaged.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
As it can't throw. This is needed to simplify the following
patch that will always close the reader in read_page.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
return reader lifecycle policy's destroy_reader future
so it can be waited on by caller (multishard_combining_reader::close).
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Move the logic in ~foreign_reader to close()
to wait on the read_ahead future and close the underlying
reader on the remote shard. Still call close in the background
in ~foreign_reader if destroyed without closing to keep the current
behavior, but warn about it, until it's proved to be unneeded.
Also, added on_iternal_error in close if _read_ahead_future
is engaged but _reader is not, since this must never happen
and we wait on the _read_ahead_future without the _reader.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
These will be called by merging_reader::close via
mutation_fragment_merger::close in the following patches.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Such that the holder, that is responsible for closing the
read_context before destroying it, holds it uniquely.
cache_flat_mutation_reader may be constructed either
with a read_context&, where it knows that the read_context
is owned externally, by the caller, or it could
be constructed with a std::unique_ptr<read_context> in
which case it assumes ownership of the read_context
and it is now responsible for closing it.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
