6a62aca3a9
Will be used to synchronize long-running tablet operations with topology coordinator. It blocks barriers like erm_ptr, but refreshes if change is irrelevant, so behaves as if the erm_ptr's scope was narrowed down to a single tablet.
60 lines
1.9 KiB
C++
60 lines
1.9 KiB
C++
/*
|
|
* Copyright (C) 2023-present ScyllaDB
|
|
*/
|
|
|
|
/*
|
|
* SPDX-License-Identifier: AGPL-3.0-or-later
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include "replica/database.hh"
|
|
#include "locator/tablets.hh"
|
|
#include "locator/abstract_replication_strategy.hh"
|
|
|
|
namespace locator {
|
|
|
|
/// A holder for table's effective_replication_map which
|
|
/// automatically switches to the latest one as long as it
|
|
/// does not affect the tablet associated with this guard.
|
|
///
|
|
/// This is useful for tracking long-running operations in
|
|
/// the context of a single tablet which we don't want to
|
|
/// block topology barriers for other tablets, only barriers for
|
|
/// this tablet.
|
|
class tablet_metadata_guard {
|
|
lw_shared_ptr<replica::table> _table;
|
|
global_tablet_id _tablet;
|
|
effective_replication_map_ptr _erm;
|
|
std::optional<tablet_transition_stage> _stage;
|
|
seastar::abort_source _abort_source;
|
|
optimized_optional<seastar::abort_source::subscription> _callback;
|
|
private:
|
|
void subscribe();
|
|
void check() noexcept;
|
|
public:
|
|
tablet_metadata_guard(replica::table& table, global_tablet_id tablet);
|
|
|
|
/// Returns an abort_source which is signaled when effective_replication_map changes
|
|
/// in a way which is relevant for the tablet associated with this guard.
|
|
/// When this happens, the guard stops refreshing the effective_replication_map,
|
|
/// which will block topology coordinator barriers until the guard is destroyed.
|
|
///
|
|
/// The abort_source is valid as long as this instance is alive.
|
|
seastar::abort_source& get_abort_source() {
|
|
return _abort_source;
|
|
}
|
|
|
|
locator::token_metadata_ptr get_token_metadata() {
|
|
return _erm->get_token_metadata_ptr();
|
|
}
|
|
|
|
/// Returns tablet_map for the table of the tablet associated with this guard.
|
|
/// The result is valid until the next deferring point.
|
|
const locator::tablet_map& get_tablet_map() {
|
|
return get_token_metadata()->tablets().get_tablet_map(_tablet.table);
|
|
}
|
|
};
|
|
|
|
} // namespace locator
|