f3eade2f62
Drop the AGPL license in favor of a source-available license. See the blog post [1] for details. [1] https://www.scylladb.com/2024/12/18/why-were-moving-to-a-source-available-license/
81 lines
2.8 KiB
C++
81 lines
2.8 KiB
C++
/*
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* Copyright 2021-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
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*/
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#pragma once
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#include "seastarx.hh"
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#include <seastar/core/sharded.hh>
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#include <seastar/core/abort_source.hh>
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#include <seastar/core/semaphore.hh>
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#include "data_dictionary/data_dictionary.hh"
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namespace gms {
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class gossiper;
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}
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namespace replica {
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class database;
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}
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namespace service {
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class storage_proxy;
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}
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namespace alternator {
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// expiration_service is a sharded service responsible for cleaning up expired
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// items in all tables with per-item expiration enabled. Currently, this means
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// Alternator tables with TTL configured via a UpdateTimeToLeave request.
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class expiration_service final : public seastar::peering_sharded_service<expiration_service> {
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public:
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// Object holding per-shard statistics related to the expiration service.
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// While this object is alive, these metrics are also registered to be
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// visible by the metrics REST API, with the "expiration_" prefix.
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class stats {
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public:
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stats();
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uint64_t scan_passes = 0;
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uint64_t scan_table = 0;
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uint64_t items_deleted = 0;
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uint64_t secondary_ranges_scanned = 0;
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private:
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// The metric_groups object holds this stat object's metrics registered
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// as long as the stats object is alive.
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seastar::metrics::metric_groups _metrics;
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};
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private:
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data_dictionary::database _db;
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service::storage_proxy& _proxy;
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gms::gossiper& _gossiper;
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// _end is set by start(), and resolves when the the background service
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// started by it ends. To ask the background service to end, _abort_source
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// should be triggered. stop() below uses both _abort_source and _end.
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std::optional<future<>> _end;
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abort_source _abort_source;
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// Ensures that at most 1 page of scan results at a time is processed by the TTL service
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named_semaphore _page_sem{1, named_semaphore_exception_factory{"alternator_ttl"}};
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bool shutting_down() { return _abort_source.abort_requested(); }
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stats _expiration_stats;
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public:
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// sharded_service<expiration_service>::start() creates this object on
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// all shards, so calls this constructor on each shard. Later, the
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// additional start() function should be invoked on all shards.
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expiration_service(data_dictionary::database, service::storage_proxy&, gms::gossiper&);
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future<> start();
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future<> run();
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// sharded_service<expiration_service>::stop() calls the following stop()
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// method on each shard. This stop() asks the service on this shard to
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// shut down as quickly as it can. The returned future indicates when the
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// service is no longer running.
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// stop() may be called even before start(), but may only be called once -
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// calling it twice will result in an exception.
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future<> stop();
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};
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} // namespace alternator
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