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// write_conflict_exception.h
/**
* 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 <exception>
#include "mongo/util/assert_util.h"
#define MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN \
do { \
int wcr__Attempts = 0; \
do { \
try
#define MONGO_WRITE_CONFLICT_RETRY_LOOP_END(PTXN, OPSTR, NSSTR) \
catch (const ::mongo::WriteConflictException& wce) { \
const OperationContext* ptxn = (PTXN); \
++CurOp::get(ptxn)->debug().writeConflicts; \
wce.logAndBackoff(wcr__Attempts, (OPSTR), (NSSTR)); \
++wcr__Attempts; \
ptxn->recoveryUnit()->abandonSnapshot(); \
continue; \
} \
break; \
} \
while (true) \
; \
} \
while (false) \
;
namespace mongo {
/**
* This is thrown if during a write, two or more operations conflict with each other.
* For example if two operations get the same version of a document, and then both try to
* modify that document, this exception will get thrown by one of them.
*/
class WriteConflictException : public DBException {
public:
WriteConflictException();
/**
* Will log a message if sensible and will do an exponential backoff to make sure
* we don't hammer the same doc over and over.
* @param attempt - what attempt is this, 1 based
* @param operation - e.g. "update"
*/
static void logAndBackoff(int attempt, StringData operation, StringData ns);
/**
* If true, will call printStackTrace on every WriteConflictException created.
* Can be set via setParameter named traceWriteConflictExceptions.
*/
static std::atomic<bool> trace; // NOLINT
};
}
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