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/**
* Copyright (C) 2015 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
namespace mongo {
/**
* UPGRADE HISTORY
*
* The enum below documents the version changes to *both* the config server data layout
* and the versioning protocol between clients (i.e. the set of calls between mongos and
* mongod).
*
* Friendly notice:
*
* EVERY CHANGE EITHER IN CONFIG LAYOUT AND IN S/D PROTOCOL MUST BE RECORDED HERE BY AN INCREASE
* IN THE VERSION AND BY TAKING THE FOLLOWING STEPS. (IF YOU DON'T UNDERSTAND THESE STEPS, YOU
* SHOULD PROBABLY NOT BE UPGRADING THE VERSIONS BY YOURSELF.)
*
* + A new entry in the UpgradeHistory enum is created
* + The CURRENT_CONFIG_VERSION below is incremented to that version
* + There should be a determination if the MIN_COMPATIBLE_CONFIG_VERSION should be increased or
* not. This means determining if, by introducing the changes to layout and/or protocol, the
* new mongos/d can co-exist in a cluster with the old ones.
* + If layout changes are involved, there should be a corresponding layout upgrade routine. See
* for instance config_upgrade_vX_to_vY.cpp.
* + Again, if a layout change occurs, the base upgrade method, config_upgrade_v0_to_vX.cpp must
* be upgraded. This means that all new clusters will start at the newest versions.
*
*/
enum UpgradeHistory {
/**
* The empty version, reported when there is no config server data
*/
UpgradeHistory_EmptyVersion = 0,
/**
* The unreported version older mongoses used before config.version collection existed
*
* If there is a config.shards/databases/collections collection but no config.version
* collection, version 1 is assumed
*/
UpgradeHistory_UnreportedVersion = 1,
/**
* NOTE: We skip version 2 here since it is very old and we shouldn't see it in the wild.
*
* Do not skip upgrade versions in the future.
*/
/**
* Base version used by pre-2.4 mongoses with no collection epochs.
*/
UpgradeHistory_NoEpochVersion = 3,
/**
* Version upgrade which added collection epochs to all sharded collections and
* chunks.
*
* Also:
* + Version document in config.version now of the form:
* { minVersion : X, currentVersion : Y, clusterId : OID(...) }
* + Mongos pings include a "mongoVersion" field indicating the mongos version
* + Mongos pings include a "configVersion" field indicating the current config version
* + Mongos explicitly ignores any collection with a "primary" field
*/
UpgradeHistory_MandatoryEpochVersion = 4,
/**
* Version upgrade with the following changes:
*
* + Dropping a collection from mongos now waits for the chunks to be removed from the
* config server before contacting each shard. Because of this, mongos should be
* upgraded first before mongod or never drop collections during upgrade.
*/
UpgradeHistory_DummyBumpPre2_6 = 5,
/**
* Version upgrade with the following changes:
*
* + "_secondaryThrottle" field for config.settings now accepts write concern
* specifications.
* + config.locks { ts: 1 } index is no longer unique.
*/
UpgradeHistory_DummyBumpPre2_8 = 6, // Note: 2.8 is also known as 3.0.
};
// Earliest version we're compatible with
const int MIN_COMPATIBLE_CONFIG_VERSION = UpgradeHistory_DummyBumpPre2_6;
// Latest version we know how to communicate with
const int CURRENT_CONFIG_VERSION = UpgradeHistory_DummyBumpPre2_8;
} // namespace mongo
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