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/* Copyright (C) 2003 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
//
// ndbapi_example3.cpp: Error handling and transaction retries
//
// Execute ndbapi_example1 to create the table "MYTABLENAME"
// before executing this program.
//
// There are many ways to program using the NDB API. In this example
// we execute two inserts in the same transaction using
// NdbConnection::Ndbexecute(NoCommit).
//
// Transaction failing is handled by re-executing the transaction
// in case of non-permanent transaction errors.
// Application errors (i.e. errors at points marked with APIERROR)
// should be handled by the application programmer.
#include <NdbApi.hpp>
// Used for cout
#include <iostream>
// Used for sleep (use your own version of sleep)
#include <unistd.h>
#define TIME_TO_SLEEP_BETWEEN_TRANSACTION_RETRIES 1
//
// APIERROR prints an NdbError object
//
#define APIERROR(error) \
{ std::cout << "API ERROR: " << error.code << " " << error.message \
<< std::endl \
<< " " << "Status: " << error.status \
<< ", Classification: " << error.classification << std::endl\
<< " " << "File: " << __FILE__ \
<< " (Line: " << __LINE__ << ")" << std::endl \
; \
}
//
// CONERROR prints all error info regarding an NdbConnection
//
#define CONERROR(ndbConnection) \
{ NdbError error = ndbConnection->getNdbError(); \
std::cout << "CON ERROR: " << error.code << " " << error.message \
<< std::endl \
<< " " << "Status: " << error.status \
<< ", Classification: " << error.classification << std::endl \
<< " " << "File: " << __FILE__ \
<< " (Line: " << __LINE__ << ")" << std::endl \
; \
printTransactionError(ndbConnection); \
}
void printTransactionError(NdbConnection *ndbConnection) {
const NdbOperation *ndbOp = NULL;
int i=0;
/****************************************************************
* Print NdbError object of every operations in the transaction *
****************************************************************/
while ((ndbOp = ndbConnection->getNextCompletedOperation(ndbOp)) != NULL) {
NdbError error = ndbOp->getNdbError();
std::cout << " OPERATION " << i+1 << ": "
<< error.code << " " << error.message << std::endl
<< " Status: " << error.status
<< ", Classification: " << error.classification << std::endl;
i++;
}
}
//
// Example insert
// @param myNdb Ndb object representing NDB Cluster
// @param myConnection NdbConnection used for transaction
// @param error NdbError object returned in case of errors
// @return -1 in case of failures, 0 otherwise
//
int insert(int transactionId, NdbConnection* myConnection) {
NdbOperation *myOperation; // For other operations
myOperation = myConnection->getNdbOperation("MYTABLENAME");
if (myOperation == NULL) return -1;
if (myOperation->insertTuple() ||
myOperation->equal("ATTR1", transactionId) ||
myOperation->setValue("ATTR2", transactionId)) {
APIERROR(myOperation->getNdbError());
exit(-1);
}
return myConnection->execute(NoCommit);
}
//
// Execute function which re-executes (tries 10 times) the transaction
// if there are temporary errors (e.g. the NDB Cluster is overloaded).
// @return -1 failure, 1 success
//
int executeInsertTransaction(int transactionId, Ndb* myNdb) {
int result = 0; // No result yet
int noOfRetriesLeft = 10;
NdbConnection *myConnection; // For other transactions
NdbError ndberror;
while (noOfRetriesLeft > 0 && !result) {
/*********************************
* Start and execute transaction *
*********************************/
myConnection = myNdb->startTransaction();
if (myConnection == NULL) {
APIERROR(myNdb->getNdbError());
ndberror = myNdb->getNdbError();
result = -1; // Failure
} else if (insert(transactionId, myConnection) ||
insert(10000+transactionId, myConnection) ||
myConnection->execute(Commit)) {
CONERROR(myConnection);
ndberror = myConnection->getNdbError();
result = -1; // Failure
} else {
result = 1; // Success
}
/**********************************
* If failure, then analyze error *
**********************************/
if (result == -1) {
switch (ndberror.status) {
case NdbError::Success:
break;
case NdbError::TemporaryError:
std::cout << "Retrying transaction..." << std::endl;
sleep(TIME_TO_SLEEP_BETWEEN_TRANSACTION_RETRIES);
--noOfRetriesLeft;
result = 0; // No completed transaction yet
break;
case NdbError::UnknownResult:
case NdbError::PermanentError:
std::cout << "No retry of transaction..." << std::endl;
result = -1; // Permanent failure
break;
}
}
/*********************
* Close transaction *
*********************/
if (myConnection != NULL) {
myNdb->closeTransaction(myConnection);
}
}
if (result != 1) exit(-1);
return result;
}
int main()
{
Ndb* myNdb = new Ndb( "TEST_DB_1" ); // Object representing the database
/*******************************************
* Initialize NDB and wait until its ready *
*******************************************/
if (myNdb->init() == -1) {
APIERROR(myNdb->getNdbError());
exit(-1);
}
if (myNdb->waitUntilReady(30) != 0) {
std::cout << "NDB was not ready within 30 secs." << std::endl;
exit(-1);
}
/************************************
* Execute some insert transactions *
************************************/
for (int i = 10000; i < 20000; i++) {
executeInsertTransaction(i, myNdb);
}
delete myNdb;
}
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