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MongoDbClient.java
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Tue, Jun 4, 04:18

MongoDbClient.java
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/**
* MongoDB client binding for YCSB.
*
* Submitted by Yen Pai on 5/11/2010.
*
* https://gist.github.com/000a66b8db2caf42467b#file_mongo_db.java
*
*/
package com.yahoo.ycsb.db;
import com.mongodb.*;
import com.yahoo.ycsb.ByteArrayByteIterator;
import com.yahoo.ycsb.ByteIterator;
import com.yahoo.ycsb.DB;
import com.yahoo.ycsb.DBException;
import java.util.*;
import java.util.concurrent.atomic.AtomicInteger;
/**
* MongoDB client for YCSB framework.
*
* Properties to set:
*
* mongodb.url=mongodb://localhost:27017 mongodb.database=ycsb
* mongodb.writeConcern=normal
*
* @author ypai
*/
public class MongoDbClient extends DB {
/** Used to include a field in a response. */
protected static final Integer INCLUDE = Integer.valueOf(1);
/** A singleton Mongo instance. */
private static Mongo mongo;
/** The default write concern for the test. */
private static WriteConcern writeConcern;
/** The database to access. */
private static String database;
/** Count the number of times initialized to teardown on the last {@link #cleanup()}. */
private static final AtomicInteger initCount = new AtomicInteger(0);
/**
* Initialize any state for this DB.
* Called once per DB instance; there is one DB instance per client thread.
*/
@Override
public void init() throws DBException {
initCount.incrementAndGet();
synchronized (INCLUDE) {
if (mongo != null) {
return;
}
// initialize MongoDb driver
Properties props = getProperties();
String url = props.getProperty("mongodb.url",
"mongodb://localhost:27017");
if (url.contains(",")) {
//pick one and random
String[] urls = url.split(",");
int index = new Random().nextInt(urls.length);
url = urls[index];
System.out.printf("Using Mongo URL: %s\n", url);
}
database = props.getProperty("mongodb.database", "ycsb");
String writeConcernType = props.getProperty("mongodb.writeConcern",
"safe").toLowerCase();
final String maxConnections = props.getProperty(
"mongodb.maxconnections", "10");
if ("none".equals(writeConcernType)) {
writeConcern = WriteConcern.NONE;
}
else if ("safe".equals(writeConcernType)) {
writeConcern = WriteConcern.SAFE;
}
else if ("normal".equals(writeConcernType)) {
writeConcern = WriteConcern.NORMAL;
}
else if ("fsync_safe".equals(writeConcernType)) {
writeConcern = WriteConcern.FSYNC_SAFE;
}
else if ("replicas_safe".equals(writeConcernType)) {
writeConcern = WriteConcern.REPLICAS_SAFE;
}
else {
System.err
.println("ERROR: Invalid writeConcern: '"
+ writeConcernType
+ "'. "
+ "Must be [ none | safe | normal | fsync_safe | replicas_safe ]");
System.exit(1);
}
try {
// strip out prefix since Java driver doesn't currently support
// standard connection format URL yet
// http://www.mongodb.org/display/DOCS/Connections
if (url.startsWith("mongodb://")) {
url = url.substring(10);
}
// need to append db to url.
url += "/" + database;
System.out.println("new database url = " + url);
MongoOptions options = new MongoOptions();
options.connectionsPerHost = Integer.parseInt(maxConnections);
mongo = new Mongo(new DBAddress(url), options);
System.out.println("mongo connection created with " + url);
}
catch (Exception e1) {
System.err
.println("Could not initialize MongoDB connection pool for Loader: "
+ e1.toString());
e1.printStackTrace();
return;
}
}
}
/**
* Cleanup any state for this DB.
* Called once per DB instance; there is one DB instance per client thread.
*/
@Override
public void cleanup() throws DBException {
if (initCount.decrementAndGet() <= 0) {
try {
mongo.close();
}
catch (Exception e1) {
System.err.println("Could not close MongoDB connection pool: "
+ e1.toString());
e1.printStackTrace();
return;
}
}
}
/**
* Delete a record from the database.
*
* @param table The name of the table
* @param key The record key of the record to delete.
* @return Zero on success, a non-zero error code on error. See this class's description for a discussion of error codes.
*/
@Override
public int delete(String table, String key) {
com.mongodb.DB db = null;
try {
db = mongo.getDB(database);
db.requestStart();
DBCollection collection = db.getCollection(table);
DBObject q = new BasicDBObject().append("_id", key);
WriteResult res = collection.remove(q, writeConcern);
return res.getN() == 1 ? 0 : 1;
}
catch (Exception e) {
System.err.println(e.toString());
return 1;
}
finally {
if (db != null) {
db.requestDone();
}
}
}
/**
* Insert a record in the database. Any field/value pairs in the specified values HashMap will be written into the record with the specified
* record key.
*
* @param table The name of the table
* @param key The record key of the record to insert.
* @param values A HashMap of field/value pairs to insert in the record
* @return Zero on success, a non-zero error code on error. See this class's description for a discussion of error codes.
*/
@Override
public int insert(String table, String key,
HashMap<String, ByteIterator> values) {
com.mongodb.DB db = null;
try {
db = mongo.getDB(database);
db.requestStart();
DBCollection collection = db.getCollection(table);
DBObject r = new BasicDBObject().append("_id", key);
for (String k : values.keySet()) {
r.put(k, values.get(k).toArray());
}
WriteResult res = collection.insert(r, writeConcern);
return res.getError() == null ? 0 : 1;
}
catch (Exception e) {
e.printStackTrace();
return 1;
}
finally {
if (db != null) {
db.requestDone();
}
}
}
/**
* Read a record from the database. Each field/value pair from the result will be stored in a HashMap.
*
* @param table The name of the table
* @param key The record key of the record to read.
* @param fields The list of fields to read, or null for all of them
* @param result A HashMap of field/value pairs for the result
* @return Zero on success, a non-zero error code on error or "not found".
*/
@Override
@SuppressWarnings("unchecked")
public int read(String table, String key, Set<String> fields,
HashMap<String, ByteIterator> result) {
com.mongodb.DB db = null;
try {
db = mongo.getDB(database);
db.requestStart();
DBCollection collection = db.getCollection(table);
DBObject q = new BasicDBObject().append("_id", key);
DBObject fieldsToReturn = new BasicDBObject();
DBObject queryResult = null;
if (fields != null) {
Iterator<String> iter = fields.iterator();
while (iter.hasNext()) {
fieldsToReturn.put(iter.next(), INCLUDE);
}
queryResult = collection.findOne(q, fieldsToReturn);
}
else {
queryResult = collection.findOne(q);
}
if (queryResult != null) {
result.putAll(queryResult.toMap());
}
return queryResult != null ? 0 : 1;
}
catch (Exception e) {
System.err.println(e.toString());
return 1;
}
finally {
if (db != null) {
db.requestDone();
}
}
}
/**
* Update a record in the database. Any field/value pairs in the specified values HashMap will be written into the record with the specified
* record key, overwriting any existing values with the same field name.
*
* @param table The name of the table
* @param key The record key of the record to write.
* @param values A HashMap of field/value pairs to update in the record
* @return Zero on success, a non-zero error code on error. See this class's description for a discussion of error codes.
*/
@Override
public int update(String table, String key,
HashMap<String, ByteIterator> values) {
com.mongodb.DB db = null;
try {
db = mongo.getDB(database);
db.requestStart();
DBCollection collection = db.getCollection(table);
DBObject q = new BasicDBObject().append("_id", key);
DBObject u = new BasicDBObject();
DBObject fieldsToSet = new BasicDBObject();
Iterator<String> keys = values.keySet().iterator();
while (keys.hasNext()) {
String tmpKey = keys.next();
fieldsToSet.put(tmpKey, values.get(tmpKey).toArray());
}
u.put("$set", fieldsToSet);
WriteResult res = collection.update(q, u, false, false,
writeConcern);
return res.getN() == 1 ? 0 : 1;
}
catch (Exception e) {
System.err.println(e.toString());
return 1;
}
finally {
if (db != null) {
db.requestDone();
}
}
}
/**
* Perform a range scan for a set of records in the database. Each field/value pair from the result will be stored in a HashMap.
*
* @param table The name of the table
* @param startkey The record key of the first record to read.
* @param recordcount The number of records to read
* @param fields The list of fields to read, or null for all of them
* @param result A Vector of HashMaps, where each HashMap is a set field/value pairs for one record
* @return Zero on success, a non-zero error code on error. See this class's description for a discussion of error codes.
*/
@Override
public int scan(String table, String startkey, int recordcount,
Set<String> fields, Vector<HashMap<String, ByteIterator>> result) {
com.mongodb.DB db = null;
try {
db = mongo.getDB(database);
db.requestStart();
DBCollection collection = db.getCollection(table);
// { "_id":{"$gte":startKey, "$lte":{"appId":key+"\uFFFF"}} }
DBObject scanRange = new BasicDBObject().append("$gte", startkey);
DBObject q = new BasicDBObject().append("_id", scanRange);
DBCursor cursor = collection.find(q).limit(recordcount);
while (cursor.hasNext()) {
// toMap() returns a Map, but result.add() expects a
// Map<String,String>. Hence, the suppress warnings.
HashMap<String, ByteIterator> resultMap = new HashMap<String, ByteIterator>();
DBObject obj = cursor.next();
fillMap(resultMap, obj);
result.add(resultMap);
}
return 0;
}
catch (Exception e) {
System.err.println(e.toString());
return 1;
}
finally {
if (db != null) {
db.requestDone();
}
}
}
/**
* TODO - Finish
*
* @param resultMap
* @param obj
*/
@SuppressWarnings("unchecked")
protected void fillMap(HashMap<String, ByteIterator> resultMap, DBObject obj) {
Map<String, Object> objMap = obj.toMap();
for (Map.Entry<String, Object> entry : objMap.entrySet()) {
if (entry.getValue() instanceof byte[]) {
resultMap.put(entry.getKey(), new ByteArrayByteIterator(
(byte[]) entry.getValue()));
}
}
}
}

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