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DBWrapper.java
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Mon, May 13, 17:50

DBWrapper.java
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/**
* Copyright (c) 2010 Yahoo! Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you
* may not use this file except in compliance with the License. You
* may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied. See the License for the specific language governing
* permissions and limitations under the License. See accompanying
* LICENSE file.
*/
package com.yahoo.ycsb;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Properties;
import java.util.Set;
import java.util.Vector;
import org.apache.htrace.core.Tracer;
import org.apache.htrace.core.TraceScope;
import com.yahoo.ycsb.measurements.Measurements;
/**
* Wrapper around a "real" DB that measures latencies and counts return codes.
* Also reports latency separately between OK and failed operations.
*/
public class DBWrapper extends DB
{
private final DB _db;
private final Measurements _measurements;
private final Tracer _tracer;
private boolean reportLatencyForEachError = false;
private HashSet<String> latencyTrackedErrors = new HashSet<String>();
private static final String REPORT_LATENCY_FOR_EACH_ERROR_PROPERTY =
"reportlatencyforeacherror";
private static final String REPORT_LATENCY_FOR_EACH_ERROR_PROPERTY_DEFAULT =
"false";
private static final String LATENCY_TRACKED_ERRORS_PROPERTY =
"latencytrackederrors";
private final String SCOPE_STRING_CLEANUP;
private final String SCOPE_STRING_DELETE;
private final String SCOPE_STRING_INIT;
private final String SCOPE_STRING_INSERT;
private final String SCOPE_STRING_READ;
private final String SCOPE_STRING_SCAN;
private final String SCOPE_STRING_UPDATE;
public DBWrapper(final DB db, final Tracer tracer)
{
_db=db;
_measurements=Measurements.getMeasurements();
_tracer = tracer;
final String simple = db.getClass().getSimpleName();
SCOPE_STRING_CLEANUP = simple + "#cleanup";
SCOPE_STRING_DELETE = simple + "#delete";
SCOPE_STRING_INIT = simple + "#init";
SCOPE_STRING_INSERT = simple + "#insert";
SCOPE_STRING_READ = simple + "#read";
SCOPE_STRING_SCAN = simple + "#scan";
SCOPE_STRING_UPDATE = simple + "#update";
}
/**
* Set the properties for this DB.
*/
public void setProperties(Properties p)
{
_db.setProperties(p);
}
/**
* Get the set of properties for this DB.
*/
public Properties getProperties()
{
return _db.getProperties();
}
/**
* Initialize any state for this DB.
* Called once per DB instance; there is one DB instance per client thread.
*/
public void init() throws DBException
{
try (final TraceScope span = _tracer.newScope(SCOPE_STRING_INIT)) {
_db.init();
this.reportLatencyForEachError = Boolean.parseBoolean(getProperties().
getProperty(REPORT_LATENCY_FOR_EACH_ERROR_PROPERTY,
REPORT_LATENCY_FOR_EACH_ERROR_PROPERTY_DEFAULT));
if (!reportLatencyForEachError) {
String latencyTrackedErrors = getProperties().getProperty(
LATENCY_TRACKED_ERRORS_PROPERTY, null);
if (latencyTrackedErrors != null) {
this.latencyTrackedErrors = new HashSet<String>(Arrays.asList(
latencyTrackedErrors.split(",")));
}
}
System.err.println("DBWrapper: report latency for each error is " +
this.reportLatencyForEachError + " and specific error codes to track" +
" for latency are: " + this.latencyTrackedErrors.toString());
}
}
/**
* Cleanup any state for this DB.
* Called once per DB instance; there is one DB instance per client thread.
*/
public void cleanup() throws DBException
{
try (final TraceScope span = _tracer.newScope(SCOPE_STRING_CLEANUP)) {
long ist=_measurements.getIntendedtartTimeNs();
long st = System.nanoTime();
_db.cleanup();
long en=System.nanoTime();
measure("CLEANUP", Status.OK, ist, st, en);
}
}
/**
* 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 The result of the operation.
*/
public Status read(String table, String key, Set<String> fields,
HashMap<String,ByteIterator> result)
{
try (final TraceScope span = _tracer.newScope(SCOPE_STRING_READ)) {
long ist=_measurements.getIntendedtartTimeNs();
long st = System.nanoTime();
Status res=_db.read(table,key,fields,result);
long en=System.nanoTime();
measure("READ", res, ist, st, en);
_measurements.reportStatus("READ", res);
return res;
}
}
/**
* 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 The result of the operation.
*/
public Status scan(String table, String startkey, int recordcount,
Set<String> fields, Vector<HashMap<String,ByteIterator>> result)
{
try (final TraceScope span = _tracer.newScope(SCOPE_STRING_SCAN)) {
long ist=_measurements.getIntendedtartTimeNs();
long st = System.nanoTime();
Status res=_db.scan(table,startkey,recordcount,fields,result);
long en=System.nanoTime();
measure("SCAN", res, ist, st, en);
_measurements.reportStatus("SCAN", res);
return res;
}
}
private void measure(String op, Status result, long intendedStartTimeNanos,
long startTimeNanos, long endTimeNanos) {
String measurementName = op;
if (result != Status.OK) {
if (this.reportLatencyForEachError ||
this.latencyTrackedErrors.contains(result.getName())) {
measurementName = op + "-" + result.getName();
} else {
measurementName = op + "-FAILED";
}
}
_measurements.measure(measurementName,
(int)((endTimeNanos-startTimeNanos)/1000));
_measurements.measureIntended(measurementName,
(int)((endTimeNanos-intendedStartTimeNanos)/1000));
}
/**
* 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 The result of the operation.
*/
public Status update(String table, String key,
HashMap<String,ByteIterator> values)
{
try (final TraceScope span = _tracer.newScope(SCOPE_STRING_UPDATE)) {
long ist=_measurements.getIntendedtartTimeNs();
long st = System.nanoTime();
Status res=_db.update(table,key,values);
long en=System.nanoTime();
measure("UPDATE", res, ist, st, en);
_measurements.reportStatus("UPDATE", res);
return res;
}
}
/**
* 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 The result of the operation.
*/
public Status insert(String table, String key,
HashMap<String,ByteIterator> values)
{
try (final TraceScope span = _tracer.newScope(SCOPE_STRING_INSERT)) {
long ist=_measurements.getIntendedtartTimeNs();
long st = System.nanoTime();
Status res=_db.insert(table,key,values);
long en=System.nanoTime();
measure("INSERT", res, ist, st, en);
_measurements.reportStatus("INSERT", res);
return res;
}
}
/**
* Delete a record from the database.
*
* @param table The name of the table
* @param key The record key of the record to delete.
* @return The result of the operation.
*/
public Status delete(String table, String key)
{
try (final TraceScope span = _tracer.newScope(SCOPE_STRING_DELETE)) {
long ist=_measurements.getIntendedtartTimeNs();
long st = System.nanoTime();
Status res=_db.delete(table,key);
long en=System.nanoTime();
measure("DELETE", res, ist, st, en);
_measurements.reportStatus("DELETE", res);
return res;
}
}
}

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