write_conflict_exception.h

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// write_conflict_exception.h

#pragma once

#include <exception>

#include "mongo/base/string_data.h"
#include "mongo/db/curop.h"
#include "mongo/util/assert_util.h"

namespace mongo {

class WriteConflictException final : public DBException {
public:
    WriteConflictException();

    static void logAndBackoff(int attempt, StringData operation, StringData ns);

    static AtomicBool trace;

private:
    void defineOnlyInFinalSubclassToPreventSlicing() final {}
};

template <typename F>
auto writeConflictRetry(OperationContext* opCtx, StringData opStr, StringData ns, F&& f) {
    invariant(opCtx);
    invariant(opCtx->lockState());
    invariant(opCtx->recoveryUnit());

    if (opCtx->lockState()->inAWriteUnitOfWork()) {
        return f();
    }

    int attempts = 0;
    while (true) {
        try {
            return f();
        } catch (WriteConflictException const&) {
            ++CurOp::get(opCtx)->debug().writeConflicts;
            WriteConflictException::logAndBackoff(attempts, opStr, ns);
            ++attempts;
            opCtx->recoveryUnit()->abandonSnapshot();
        }
    }
}

}  // namespace mongo