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/**
* Copyright (C) 2014 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include "mongo/db/repl/optime.h"
namespace mongo {
class BSONObj;
class OperationContext;
namespace repl {
struct BatchBoundaries {
BatchBoundaries(const OpTime s, const OpTime e) : start(s), end(e) {}
const OpTime start;
const OpTime end;
};
enum class DurableRequirement {
None, // Does not require any durability of the write.
Strong, // Requires journal or checkpoint write.
};
/**
* Helper functions for maintaining a single document in the local.replset.minvalid collection.
*
* When a member reaches its minValid optime it is in a consistent state. Thus, minValid is
* set as the last step in initial sync. At the beginning of initial sync, doingInitialSync
* is appended onto minValid to indicate that initial sync was started but has not yet
* completed.
*
* The document is also updated during "normal" sync. The optime of the last op in each batch is
* used to set minValid, along with a "begin" field to demark the start and the fact that a batch
* is active. When the batch is done the "begin" field is removed to indicate that we are in a
* consistent state when the batch has been fully applied.
*
* Example of all fields:
* { _id:...,
* doingInitialSync: true // initial sync is active
* ts:..., t:... // end-OpTime
* begin: {ts:..., t:...} // a batch is currently being applied, and not consistent
* }
*/
/**
* The initial sync flag is used to durably record that initial sync has not completed.
*
* These operations wait for durable writes (which will block on journaling/checkpointing).
*/
void clearInitialSyncFlag(OperationContext* txn);
void setInitialSyncFlag(OperationContext* txn);
/**
* Returns true if the initial sync flag is set (and presumed active).
*/
bool getInitialSyncFlag();
/**
* Returns the bounds of the current apply batch, if active. If start is null/missing, and
* end is equal to the last oplog entry then we are in a consistent state and ready for reads.
*/
BatchBoundaries getMinValid(OperationContext* txn);
/**
* The minValid value is the earliest (minimum) Timestamp that must be applied in order to
* consider the dataset consistent.
*
* This is called when a batch finishes.
*
* Wait for durable writes (which will block on journaling/checkpointing) when specified.
*
*/
void setMinValid(OperationContext* ctx, const OpTime& endOpTime, const DurableRequirement durReq);
/**
* The bounds indicate an apply is active and we are not in a consistent state to allow reads
* or transition from a non-visible state to primary/secondary.
*/
void setMinValid(OperationContext* ctx, const BatchBoundaries& boundaries);
}
}
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