mariadb/ndb/examples/ndbapi_async_example/ndbapi_async.cpp
2004-09-15 14:52:39 +02:00

496 lines
12 KiB
C++

/* 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_async.cpp:
* Illustrates how to use callbacks and error handling using the asynchronous
* part of the NDBAPI.
*
* Classes and methods in NDBAPI used in this example:
*
* Ndb
* init()
* waitUntilRead()
* getDictionary()
* startTransaction()
* closeTransaction()
* sendPollNdb()
* getNdbError()
*
* NdbConnection
* getNdbOperation()
* executeAsynchPrepare()
* getNdbError()
*
* NdbDictionary::Dictionary
* getTable()
* dropTable()
* createTable()
* getNdbError()
*
* NdbDictionary::Column
* setName()
* setType()
* setLength()
* setPrimaryKey()
* setNullable()
*
* NdbDictionary::Table
* setName()
* addColumn()
*
* NdbOperation
* insertTuple()
* equal()
* setValue()
*
*/
#include <ndb_global.h>
#include <NdbApi.hpp>
#include <NdbScanFilter.hpp>
#include <iostream> // Used for cout
/**
* Helper sleep function
*/
int
milliSleep(int milliseconds){
int result = 0;
struct timespec sleeptime;
sleeptime.tv_sec = milliseconds / 1000;
sleeptime.tv_nsec = (milliseconds - (sleeptime.tv_sec * 1000)) * 1000000;
result = nanosleep(&sleeptime, NULL);
return result;
}
/**
* error printout macro
*/
#define APIERROR(error) \
{ std::cout << "Error in " << __FILE__ << ", line:" << __LINE__ << ", code:" \
<< error.code << ", msg: " << error.message << "." << std::endl; \
exit(-1); }
#ifndef DOXYGEN_SHOULD_SKIP_INTERNAL
/**
* callback struct.
* transaction : index of the transaction in transaction[] array below
* data : the data that the transaction was modifying.
* retries : counter for how many times the trans. has been retried
*/
typedef struct {
Ndb * ndb;
int transaction;
int data;
int retries;
} async_callback_t;
/**
* Structure used in "free list" to a NdbConnection
*/
typedef struct {
NdbConnection* conn;
int used;
} transaction_t;
/**
* Free list holding transactions
*/
transaction_t transaction[1024]; //1024 - max number of outstanding
//transaction in one Ndb object
#endif
/**
* prototypes
*/
/**
* Prepare and send transaction
*/
int populate(Ndb * myNdb, int data, async_callback_t * cbData);
/**
* Error handler.
*/
bool asynchErrorHandler(NdbConnection * trans, Ndb* ndb);
/**
* Exit function
*/
void asynchExitHandler(Ndb * m_ndb) ;
/**
* Helper function used in callback(...)
*/
void closeTransaction(Ndb * ndb , async_callback_t * cb);
/**
* Function to create table
*/
int create_table(Ndb * myNdb);
/**
* stat. variables
*/
int tempErrors = 0;
int permErrors = 0;
/**
* Helper function for callback(...)
*/
void
closeTransaction(Ndb * ndb , async_callback_t * cb)
{
ndb->closeTransaction(transaction[cb->transaction].conn);
transaction[cb->transaction].conn = 0;
transaction[cb->transaction].used = 0;
cb->retries++;
}
/**
* Callback executed when transaction has return from NDB
*/
static void
callback(int result, NdbConnection* trans, void* aObject)
{
async_callback_t * cbData = (async_callback_t *)aObject;
if (result<0)
{
/**
* Error: Temporary or permanent?
*/
if (asynchErrorHandler(trans, (Ndb*)cbData->ndb))
{
closeTransaction((Ndb*)cbData->ndb, cbData);
while(populate((Ndb*)cbData->ndb, cbData->data, cbData) < 0)
milliSleep(10);
}
else
{
std::cout << "Restore: Failed to restore data "
<< "due to a unrecoverable error. Exiting..." << std::endl;
delete cbData;
asynchExitHandler((Ndb*)cbData->ndb);
}
}
else
{
/**
* OK! close transaction
*/
closeTransaction((Ndb*)cbData->ndb, cbData);
delete cbData;
}
}
/**
* Create table "GARAGE"
*/
int create_table(Ndb * myNdb)
{
NdbDictionary::Table myTable;
NdbDictionary::Column myColumn;
NdbDictionary::Dictionary* myDict = myNdb->getDictionary();
/*********************************************************
* Create a table named GARAGE if it does not exist *
*********************************************************/
if (myDict->getTable("GARAGE") != NULL)
{
std::cout << "NDB already has example table: GARAGE. "
<< "Dropping it..." << std::endl;
if(myDict->dropTable("GARAGE") == -1)
{
std::cout << "Failed to drop: GARAGE." << std::endl;
exit(1);
}
}
myTable.setName("GARAGE");
/**
* Column REG_NO
*/
myColumn.setName("REG_NO");
myColumn.setType(NdbDictionary::Column::Unsigned);
myColumn.setLength(1);
myColumn.setPrimaryKey(true);
myColumn.setNullable(false);
myTable.addColumn(myColumn);
/**
* Column BRAND
*/
myColumn.setName("BRAND");
myColumn.setType(NdbDictionary::Column::Char);
myColumn.setLength(20);
myColumn.setPrimaryKey(false);
myColumn.setNullable(false);
myTable.addColumn(myColumn);
/**
* Column COLOR
*/
myColumn.setName("COLOR");
myColumn.setType(NdbDictionary::Column::Char);
myColumn.setLength(20);
myColumn.setPrimaryKey(false);
myColumn.setNullable(false);
myTable.addColumn(myColumn);
if (myDict->createTable(myTable) == -1) {
APIERROR(myDict->getNdbError());
}
return 1;
}
void asynchExitHandler(Ndb * m_ndb)
{
if (m_ndb != NULL)
delete m_ndb;
exit(-1);
}
/* returns true if is recoverable (temporary),
* false if it is an error that is permanent.
*/
bool asynchErrorHandler(NdbConnection * trans, Ndb* ndb)
{
NdbError error = trans->getNdbError();
switch(error.status)
{
case NdbError::Success:
return false;
break;
case NdbError::TemporaryError:
/**
* The error code indicates a temporary error.
* The application should typically retry.
* (Includes classifications: NdbError::InsufficientSpace,
* NdbError::TemporaryResourceError, NdbError::NodeRecoveryError,
* NdbError::OverloadError, NdbError::NodeShutdown
* and NdbError::TimeoutExpired.)
*
* We should sleep for a while and retry, except for insufficient space
*/
if(error.classification == NdbError::InsufficientSpace)
return false;
milliSleep(10);
tempErrors++;
return true;
break;
case NdbError::UnknownResult:
std::cout << error.message << std::endl;
return false;
break;
default:
case NdbError::PermanentError:
switch (error.code)
{
case 499:
case 250:
milliSleep(10);
return true; // SCAN errors that can be retried. Requires restart of scan.
default:
break;
}
//ERROR
std::cout << error.message << std::endl;
return false;
break;
}
return false;
}
static int nPreparedTransactions = 0;
static int MAX_RETRIES = 10;
static int parallelism = 100;
/************************************************************************
* populate()
* 1. Prepare 'parallelism' number of insert transactions.
* 2. Send transactions to NDB and wait for callbacks to execute
*/
int populate(Ndb * myNdb, int data, async_callback_t * cbData)
{
NdbOperation* myNdbOperation; // For operations
async_callback_t * cb;
int retries = 0;
int current = 0;
for(int i=0; i<1024; i++)
{
if(transaction[i].used == 0)
{
current = i;
if (cbData == 0)
{
/**
* We already have a callback
* This is an absolutely new transaction
*/
cb = new async_callback_t;
cb->retries = 0;
}
else
{
/**
* We already have a callback
*/
cb =cbData;
retries = cbData->retries;
}
/**
* Set data used by the callback
*/
cb->ndb = myNdb; //handle to Ndb object so that we can close transaction
// in the callback (alt. make myNdb global).
cb->data = data; //this is the data we want to insert
cb->transaction = current; //This is the number (id) of this transaction
transaction[current].used = 1 ; //Mark the transaction as used
break;
}
}
if(!current)
return -1;
while(retries < MAX_RETRIES)
{
transaction[current].conn = myNdb->startTransaction();
if (transaction[current].conn == NULL) {
if (asynchErrorHandler(transaction[current].conn, myNdb))
{
/**
* no transaction to close since conn == null
*/
milliSleep(10);
retries++;
continue;
}
asynchExitHandler(myNdb);
}
// Error check. If error, then maybe table GARAGE is not in database
myNdbOperation = transaction[current].conn->getNdbOperation("GARAGE");
if (myNdbOperation == NULL)
{
if (asynchErrorHandler(transaction[current].conn, myNdb))
{
myNdb->closeTransaction(transaction[current].conn);
transaction[current].conn = 0;
milliSleep(10);
retries++;
continue;
}
asynchExitHandler(myNdb);
} // if
if(myNdbOperation->insertTuple() < 0 ||
myNdbOperation->equal("REG_NO", data) < 0 ||
myNdbOperation->setValue("BRAND", "Mercedes") <0 ||
myNdbOperation->setValue("COLOR", "Blue") < 0)
{
if (asynchErrorHandler(transaction[current].conn, myNdb))
{
myNdb->closeTransaction(transaction[current].conn);
transaction[current].conn = 0;
retries++;
milliSleep(10);
continue;
}
asynchExitHandler(myNdb);
}
/*Prepare transaction (the transaction is NOT yet sent to NDB)*/
transaction[current].conn->executeAsynchPrepare(Commit,
&callback,
cb);
/**
* When we have prepared parallelism number of transactions ->
* send the transaction to ndb.
* Next time we will deal with the transactions are in the
* callback. There we will see which ones that were successful
* and which ones to retry.
*/
if (nPreparedTransactions == parallelism-1)
{
// send-poll all transactions
// close transaction is done in callback
myNdb->sendPollNdb(3000, parallelism );
nPreparedTransactions=0;
}
else
nPreparedTransactions++;
return 1;
}
std::cout << "Unable to recover from errors. Exiting..." << std::endl;
asynchExitHandler(myNdb);
return -1;
}
int main()
{
ndb_init();
Ndb* myNdb = new Ndb( "TEST_DB" ); // Object representing the database
/*******************************************
* Initialize NDB and wait until its ready *
*******************************************/
if (myNdb->init(1024) == -1) { // Set max 1024 parallel transactions
APIERROR(myNdb->getNdbError());
}
if (myNdb->waitUntilReady(30) != 0) {
std::cout << "NDB was not ready within 30 secs." << std::endl;
exit(-1);
}
create_table(myNdb);
/**
* Initialise transaction array
*/
for(int i = 0 ; i < 1024 ; i++)
{
transaction[i].used = 0;
transaction[i].conn = 0;
}
int i=0;
/**
* Do 20000 insert transactions.
*/
while(i < 20000)
{
while(populate(myNdb,i,0)<0) // <0, no space on free list. Sleep and try again.
milliSleep(10);
i++;
}
std::cout << "Number of temporary errors: " << tempErrors << std::endl;
delete myNdb;
}