luni/src/test/java/com/google/coretests/StatsStore.java - platform/libcore-snapshot - Gitiles

 /*
  * Copyright (C) 2008 The Android Open Source Project
  *
  * 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.
  */

 package com.google.coretests;


 import junit.framework.Test;

 import java.io.File;
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;


 public class StatsStore {

     static final String sysVersion = "1.0";

     static Connection conn;
     static Statement stmt;
     static PreparedStatement insertStmt, selectByNameStmt, updateStmt;
     static PreparedStatement insertDetStmt, insertEventStmt;
     static PreparedStatement selectAllStmt;

     public static long now;

     static int compareDuration(long dur, long refDur) {
         long diff = dur - refDur;
         if (diff <= 0) {
             if ((double)-diff / refDur > 0.5) return 1; // remarkably faster
             else return 0; // equivalent duration (maybe a bit faster)
         }
         else if (diff < 20) return 0; // not measurably slower: equivalent duration
         else if ((double)diff / refDur < 0.2) return 0; // just little slower: equivalent duration
         else return -1; // relevantly SLOWer
     }

     static void initStats(PerfStatCollector.Item a) {
         a.statMinDuration = a.duration;
         a.statMaxDuration = a.duration;
         a.statAvgDuration = a.duration;
         a.statCount = 1;
     }

     static void adjustStats(PerfStatCollector.Item a) {
         if (a.duration < a.statMinDuration) a.statMinDuration = a.duration;
         else
         if (a.duration > a.statMaxDuration) a.statMaxDuration = a.duration;
         a.statAvgDuration = ((a.statAvgDuration * a.statCount + a.duration) / (a.statCount + 1));
         a.statCount++;
     }

     static void adjustStatsOptimistic(PerfStatCollector.Item a) {
         adjustStats(a);
         // Could consider reducing a.statMaxDuration.
     }

     static void use1(PerfStatCollector.Item a) {
         Test test;
         int pos;
         PreparedStatement selectStmt = selectByNameStmt;
         try {
             try {
                 insertStmt.setString(1, a.test.toString());
                 insertStmt.execute();
             } catch (SQLException e) {}
             selectStmt.setString(1, a.test.toString());
             ResultSet row = selectStmt.executeQuery();
             row.first();
             pos = 1;
             a.id = row.getInt(pos); pos++;
             a.bestRes = row.getInt(pos); pos++;
             a.lastBestAt = row.getLong(pos); pos++;
             a.lastRes = row.getInt(pos); pos++;
             a.lastDuration = row.getLong(pos); pos++;
             a.statCount = row.getInt(pos); pos++;
             a.statAvgDuration = row.getDouble(pos); pos++;
             a.statMinDuration = row.getLong(pos); pos++;
             a.statMaxDuration = row.getLong(pos); pos++;
             if (a.res == 0) {
                 if (a.bestRes == 100) {
                     a.bestRes = 0; a.lastBestAt = now;
                     a.histRelevance = 0; // Good from scratch.
                     a.isTransition = false;
                     initStats(a);
                 } else if (a.bestRes != 0) {
                     a.bestRes = 0; a.lastBestAt = now;
                     a.histRelevance = 4; // "Good" for the first time:
                     a.isTransition = true; // was bad before.
                     initStats(a);
                 } else if (a.lastRes != 0) {
                     a.bestRes = 0; a.lastBestAt = now;
                     a.histRelevance = 3; // "good" again:
                     a.isTransition = true; // was bad in between.
                     adjustStats(a);
                 } else {
                     // res == lastRes == bestRes == 0:
                     int cmp = compareDuration(a.duration, a.statMinDuration);
                     if (cmp >= 0) {
                         a.bestRes = 0; a.lastBestAt = now;
                         if (cmp > 0) {
                             a.histRelevance = 2; // "Fast"er than ever before.
                             a.isTransition = true;
                             adjustStatsOptimistic(a);
                         } else if (compareDuration(a.duration, a.lastDuration) > 0) {
                             // As fast as best but faster than last run:
                             a.histRelevance = 1; // "fast" again.
                             a.isTransition = true;
                             adjustStatsOptimistic(a);
                         } else {
                             a.histRelevance = 0; // Equivalent Duration:
                             a.isTransition = false; // usual good case.
                             adjustStats(a);
                         }
                     } else {
                         if (compareDuration(a.duration, a.lastDuration) < 0) {
                             a.histRelevance = -2; // "SLOW"!!!
                             a.isTransition = true;
                             adjustStats(a);
                         } else {
                             a.histRelevance = -2; // Still "SLOW"!!!
                             a.isTransition = false; // (But NO transition!)
                             adjustStats(a);
                         }
                     }
                 }
             } else if (a.bestRes == 0) {
                 if (a.lastRes == 0) {
                     a.histRelevance = -4; // "VBAD"!!!
                     a.isTransition = true;
                 } else {
                     a.histRelevance = -4; // Still "VBAD"!!!
                     a.isTransition = false; // (But NO transition!)
                 }
                 // DON'T adjust statistics: they should reflect good runs, only.
             } else if (a.bestRes == 100) {
                 a.bestRes = -3; // Just mark as NOT good.
                 a.histRelevance = -3; // Bad (initial run).
                 a.isTransition = true;
                 initStats(a);
             } else {
                 a.histRelevance = 0; // Still Failure or Error:
                 a.isTransition = false; // usual bad case.
                 adjustStats(a);
             }
             pos = 1;
             updateStmt.setInt(pos, a.bestRes); pos++;
             updateStmt.setLong(pos, a.lastBestAt); pos++;
             updateStmt.setInt(pos, a.res); pos++;
             updateStmt.setLong(pos, a.duration); pos++;
             updateStmt.setInt(pos, a.statCount); pos++;
             updateStmt.setDouble(pos, a.statAvgDuration); pos++;
             updateStmt.setLong(pos, a.statMinDuration); pos++;
             updateStmt.setLong(pos, a.statMaxDuration); pos++;
             updateStmt.setInt(pos, a.id); pos++;
             updateStmt.execute();
             pos = 1;
             insertDetStmt.setInt(pos, a.id); pos++;
             insertDetStmt.setLong(pos, now); pos++;
             insertDetStmt.setInt(pos, a.statCount); pos++;
             insertDetStmt.setInt(pos, a.res); pos++;
             insertDetStmt.setLong(pos, a.duration); pos++;
             insertDetStmt.execute();
             if (a.isTransition) {
                 pos = 1;
                 insertEventStmt.setInt(pos, a.id); pos++;
                 insertEventStmt.setLong(pos, now); pos++;
                 insertEventStmt.setInt(pos, a.histRelevance); pos++;
                 insertEventStmt.setInt(pos, a.res); pos++;
                 insertEventStmt.setLong(pos, a.duration); pos++;
                 insertEventStmt.execute();
             }
         }
         catch (SQLException e) {
             int x = 0;
         }
     }

 //    static void use2(PerfStatCollector.Item a) {
 //    }

     static void execOrIgnore(String sql) {
         try { stmt.execute(sql); }
         catch (SQLException e) {}
     }

     static void open(String jdbcDriver, String connectionURL)
     throws Exception {
 //        try {
             Class.forName(jdbcDriver).newInstance();
             conn = DriverManager.getConnection(connectionURL);
             stmt = conn.createStatement();
             String dbVersion;
             try {
                 ResultSet res = stmt.executeQuery("SELECT id FROM Version");
                 res.first();
                 dbVersion = res.getString(1);
             }
             catch (SQLException e) {
                 dbVersion = "";
             }
             if (!dbVersion.equals(sysVersion)) {
                 execOrIgnore("DROP TABLE Test_Cases;");
                 stmt.execute("CREATE TABLE Test_Cases (" +
                         "  id INTEGER PRIMARY KEY AUTOINCREMENT, " +
                         "  name VARCHAR(255) UNIQUE, " +
                         // (best_Res != 0) ==> (last_Best_At == 0) never ran good!
                         "  best_Res INTEGER, last_Best_At INTEGER, " +
                         "  last_Res INTEGER, last_Duration INTEGER, " +
                         "  stat_Cnt INTEGER, stat_Avg NUMBER(20, 2), " +
                         "  stat_Min INTEGER, stat_Max INTEGER);");
                 execOrIgnore("DROP TABLE Test_Case_Runs;");
                 stmt.execute("CREATE TABLE Test_Case_Runs (" +
                         "  test_Id INTEGER, run_At INTEGER, " +
                         "  iteration INTEGER, res INTEGER, duration INTEGER, " +
                         "  PRIMARY KEY (test_Id, run_At));");
                 execOrIgnore("DROP TABLE Test_Case_Events;");
                 stmt.execute("CREATE TABLE Test_Case_Events (" +
                         "  test_Id INTEGER, run_At INTEGER, " +
                         "  relevance INTEGER, " +
                         "  res INTEGER, duration INTEGER, " +
                         "  PRIMARY KEY (test_Id, run_At));");
 //                stmt.execute("CREATE PROCEDURE useSample (IN pName TEXT, " +
 //                        "pRes INTEGER, pDuration INTEGER, pTime INTEGER) " +
 //                        "BEGIN " +
 //                        "  INSERT OR IGNORE INTO TestCases (name)" +
 //                        "  VALUES (pName);" +
 //                        "END;");
                 execOrIgnore("DROP TABLE Version;");
                 stmt.execute("CREATE TABLE Version(id VARCHAR(31));");
                 stmt.execute("INSERT INTO Version (id) VALUES ('" + sysVersion + "');");
             }
 //            updateStmt = conn.prepareStatement("useSample(:name, :res, :duration, :time)");
     //        firstConnection.setTransactionIsolation(Connection.TRANSACTION_SERIALIZABLE);
     //        firstStmt = firstConnection.createStatement();
     //        firstStmt.execute("create table tbl1(one varchar(10), two smallint)");
             insertStmt = conn.prepareStatement("INSERT " +
                     "INTO Test_Cases (name, stat_Cnt) VALUES (?, 0);");
             selectByNameStmt = conn.prepareStatement("SELECT id, " +
                     "  IFNULL(best_Res, 100), IFNULL(last_Best_At, 0), " +
                     "  IFNULL(last_Res, 100), IFNULL(last_Duration, 0), " +
                     "  IFNULL(stat_Cnt, 0), IFNULL(stat_Avg, 0), " +
                     "  IFNULL(stat_Min, 0), IFNULL(stat_Max, 0) " +
                     "FROM Test_Cases WHERE name = ?;");
             updateStmt = conn.prepareStatement("UPDATE Test_Cases SET " +
                     "  best_Res = ?, last_Best_At = ?, " +
                     "  last_Res = ?, last_Duration = ?, " +
                     "  stat_Cnt = ?, stat_Avg = ?, " +
                     "  stat_Min = ?, stat_Max = ? " +
                     "WHERE id = ?;");
             insertDetStmt = conn.prepareStatement("INSERT " +
                     "INTO Test_Case_Runs (test_Id, run_At, iteration, res, duration) " +
                     "VALUES (?, ?, ?, ?, ?);");
             insertEventStmt = conn.prepareStatement("INSERT " +
                     "INTO Test_Case_Events (test_Id, run_At, relevance, res, duration) " +
                     "VALUES (?, ?, ?, ?, ?);");
             selectAllStmt = conn.prepareStatement("SELECT id, name, " +
                     "last_Res, stat_Cnt, " +
                     "last_Duration, stat_Avg, stat_Min, stat_Max " +
                     "FROM Test_Cases;");

             try {
 //                ResultSet res = stmt.executeQuery("PRAGMA CACHE_SIZE;");
 //                res.first();
 //                System.out.print("CACHE_SIZE = ");
 //                System.out.println(res.getString(1));
 //                stmt.execute("PRAGMA CACHE_SIZE = 5000;");
                 stmt.execute("PRAGMA SYNCHRONOUS = OFF;");
                 stmt.execute("PRAGMA temp_store = MEMORY;");
             }
             catch (SQLException e) {
                 dbVersion = "";
             }
             stmt.close();
             conn.commit();
 //        }
 //        catch (Exception e) {
 //            conn = null;
 //        }
 //        return conn != null;
     }

     static void close() {
         try {
             conn.commit();
             conn.close();
             conn = null;
         }
         catch (Exception e) {
             conn = null;
         }
     }
 }
	/*
	* Copyright (C) 2008 The Android Open Source Project
	*
	* 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.
	*/

	package com.google.coretests;


	import junit.framework.Test;

	import java.io.File;
	import java.sql.Connection;
	import java.sql.DriverManager;
	import java.sql.PreparedStatement;
	import java.sql.ResultSet;
	import java.sql.SQLException;
	import java.sql.Statement;


	public class StatsStore {

	static final String sysVersion = "1.0";

	static Connection conn;
	static Statement stmt;
	static PreparedStatement insertStmt, selectByNameStmt, updateStmt;
	static PreparedStatement insertDetStmt, insertEventStmt;
	static PreparedStatement selectAllStmt;

	public static long now;

	static int compareDuration(long dur, long refDur) {
	long diff = dur - refDur;
	if (diff <= 0) {
	if ((double)-diff / refDur > 0.5) return 1; // remarkably faster
	else return 0; // equivalent duration (maybe a bit faster)
	}
	else if (diff < 20) return 0; // not measurably slower: equivalent duration
	else if ((double)diff / refDur < 0.2) return 0; // just little slower: equivalent duration
	else return -1; // relevantly SLOWer
	}

	static void initStats(PerfStatCollector.Item a) {
	a.statMinDuration = a.duration;
	a.statMaxDuration = a.duration;
	a.statAvgDuration = a.duration;
	a.statCount = 1;
	}

	static void adjustStats(PerfStatCollector.Item a) {
	if (a.duration < a.statMinDuration) a.statMinDuration = a.duration;
	else
	if (a.duration > a.statMaxDuration) a.statMaxDuration = a.duration;
	a.statAvgDuration = ((a.statAvgDuration * a.statCount + a.duration) / (a.statCount + 1));
	a.statCount++;
	}

	static void adjustStatsOptimistic(PerfStatCollector.Item a) {
	adjustStats(a);
	// Could consider reducing a.statMaxDuration.
	}

	static void use1(PerfStatCollector.Item a) {
	Test test;
	int pos;
	PreparedStatement selectStmt = selectByNameStmt;
	try {
	try {
	insertStmt.setString(1, a.test.toString());
	insertStmt.execute();
	} catch (SQLException e) {}
	selectStmt.setString(1, a.test.toString());
	ResultSet row = selectStmt.executeQuery();
	row.first();
	pos = 1;
	a.id = row.getInt(pos); pos++;
	a.bestRes = row.getInt(pos); pos++;
	a.lastBestAt = row.getLong(pos); pos++;
	a.lastRes = row.getInt(pos); pos++;
	a.lastDuration = row.getLong(pos); pos++;
	a.statCount = row.getInt(pos); pos++;
	a.statAvgDuration = row.getDouble(pos); pos++;
	a.statMinDuration = row.getLong(pos); pos++;
	a.statMaxDuration = row.getLong(pos); pos++;
	if (a.res == 0) {
	if (a.bestRes == 100) {
	a.bestRes = 0; a.lastBestAt = now;
	a.histRelevance = 0; // Good from scratch.
	a.isTransition = false;
	initStats(a);
	} else if (a.bestRes != 0) {
	a.bestRes = 0; a.lastBestAt = now;
	a.histRelevance = 4; // "Good" for the first time:
	a.isTransition = true; // was bad before.
	initStats(a);
	} else if (a.lastRes != 0) {
	a.bestRes = 0; a.lastBestAt = now;
	a.histRelevance = 3; // "good" again:
	a.isTransition = true; // was bad in between.
	adjustStats(a);
	} else {
	// res == lastRes == bestRes == 0:
	int cmp = compareDuration(a.duration, a.statMinDuration);
	if (cmp >= 0) {
	a.bestRes = 0; a.lastBestAt = now;
	if (cmp > 0) {
	a.histRelevance = 2; // "Fast"er than ever before.
	a.isTransition = true;
	adjustStatsOptimistic(a);
	} else if (compareDuration(a.duration, a.lastDuration) > 0) {
	// As fast as best but faster than last run:
	a.histRelevance = 1; // "fast" again.
	a.isTransition = true;
	adjustStatsOptimistic(a);
	} else {
	a.histRelevance = 0; // Equivalent Duration:
	a.isTransition = false; // usual good case.
	adjustStats(a);
	}
	} else {
	if (compareDuration(a.duration, a.lastDuration) < 0) {
	a.histRelevance = -2; // "SLOW"!!!
	a.isTransition = true;
	adjustStats(a);
	} else {
	a.histRelevance = -2; // Still "SLOW"!!!
	a.isTransition = false; // (But NO transition!)
	adjustStats(a);
	}
	}
	}
	} else if (a.bestRes == 0) {
	if (a.lastRes == 0) {
	a.histRelevance = -4; // "VBAD"!!!
	a.isTransition = true;
	} else {
	a.histRelevance = -4; // Still "VBAD"!!!
	a.isTransition = false; // (But NO transition!)
	}
	// DON'T adjust statistics: they should reflect good runs, only.
	} else if (a.bestRes == 100) {
	a.bestRes = -3; // Just mark as NOT good.
	a.histRelevance = -3; // Bad (initial run).
	a.isTransition = true;
	initStats(a);
	} else {
	a.histRelevance = 0; // Still Failure or Error:
	a.isTransition = false; // usual bad case.
	adjustStats(a);
	}
	pos = 1;
	updateStmt.setInt(pos, a.bestRes); pos++;
	updateStmt.setLong(pos, a.lastBestAt); pos++;
	updateStmt.setInt(pos, a.res); pos++;
	updateStmt.setLong(pos, a.duration); pos++;
	updateStmt.setInt(pos, a.statCount); pos++;
	updateStmt.setDouble(pos, a.statAvgDuration); pos++;
	updateStmt.setLong(pos, a.statMinDuration); pos++;
	updateStmt.setLong(pos, a.statMaxDuration); pos++;
	updateStmt.setInt(pos, a.id); pos++;
	updateStmt.execute();
	pos = 1;
	insertDetStmt.setInt(pos, a.id); pos++;
	insertDetStmt.setLong(pos, now); pos++;
	insertDetStmt.setInt(pos, a.statCount); pos++;
	insertDetStmt.setInt(pos, a.res); pos++;
	insertDetStmt.setLong(pos, a.duration); pos++;
	insertDetStmt.execute();
	if (a.isTransition) {
	pos = 1;
	insertEventStmt.setInt(pos, a.id); pos++;
	insertEventStmt.setLong(pos, now); pos++;
	insertEventStmt.setInt(pos, a.histRelevance); pos++;
	insertEventStmt.setInt(pos, a.res); pos++;
	insertEventStmt.setLong(pos, a.duration); pos++;
	insertEventStmt.execute();
	}
	}
	catch (SQLException e) {
	int x = 0;
	}
	}

	// static void use2(PerfStatCollector.Item a) {
	// }

	static void execOrIgnore(String sql) {
	try { stmt.execute(sql); }
	catch (SQLException e) {}
	}

	static void open(String jdbcDriver, String connectionURL)
	throws Exception {
	// try {
	Class.forName(jdbcDriver).newInstance();
	conn = DriverManager.getConnection(connectionURL);
	stmt = conn.createStatement();
	String dbVersion;
	try {
	ResultSet res = stmt.executeQuery("SELECT id FROM Version");
	res.first();
	dbVersion = res.getString(1);
	}
	catch (SQLException e) {
	dbVersion = "";
	}
	if (!dbVersion.equals(sysVersion)) {
	execOrIgnore("DROP TABLE Test_Cases;");
	stmt.execute("CREATE TABLE Test_Cases (" +
	" id INTEGER PRIMARY KEY AUTOINCREMENT, " +
	" name VARCHAR(255) UNIQUE, " +
	// (best_Res != 0) ==> (last_Best_At == 0) never ran good!
	" best_Res INTEGER, last_Best_At INTEGER, " +
	" last_Res INTEGER, last_Duration INTEGER, " +
	" stat_Cnt INTEGER, stat_Avg NUMBER(20, 2), " +
	" stat_Min INTEGER, stat_Max INTEGER);");
	execOrIgnore("DROP TABLE Test_Case_Runs;");
	stmt.execute("CREATE TABLE Test_Case_Runs (" +
	" test_Id INTEGER, run_At INTEGER, " +
	" iteration INTEGER, res INTEGER, duration INTEGER, " +
	" PRIMARY KEY (test_Id, run_At));");
	execOrIgnore("DROP TABLE Test_Case_Events;");
	stmt.execute("CREATE TABLE Test_Case_Events (" +
	" test_Id INTEGER, run_At INTEGER, " +
	" relevance INTEGER, " +
	" res INTEGER, duration INTEGER, " +
	" PRIMARY KEY (test_Id, run_At));");
	// stmt.execute("CREATE PROCEDURE useSample (IN pName TEXT, " +
	// "pRes INTEGER, pDuration INTEGER, pTime INTEGER) " +
	// "BEGIN " +
	// " INSERT OR IGNORE INTO TestCases (name)" +
	// " VALUES (pName);" +
	// "END;");
	execOrIgnore("DROP TABLE Version;");
	stmt.execute("CREATE TABLE Version(id VARCHAR(31));");
	stmt.execute("INSERT INTO Version (id) VALUES ('" + sysVersion + "');");
	}
	// updateStmt = conn.prepareStatement("useSample(:name, :res, :duration, :time)");
	// firstConnection.setTransactionIsolation(Connection.TRANSACTION_SERIALIZABLE);
	// firstStmt = firstConnection.createStatement();
	// firstStmt.execute("create table tbl1(one varchar(10), two smallint)");
	insertStmt = conn.prepareStatement("INSERT " +
	"INTO Test_Cases (name, stat_Cnt) VALUES (?, 0);");
	selectByNameStmt = conn.prepareStatement("SELECT id, " +
	" IFNULL(best_Res, 100), IFNULL(last_Best_At, 0), " +
	" IFNULL(last_Res, 100), IFNULL(last_Duration, 0), " +
	" IFNULL(stat_Cnt, 0), IFNULL(stat_Avg, 0), " +
	" IFNULL(stat_Min, 0), IFNULL(stat_Max, 0) " +
	"FROM Test_Cases WHERE name = ?;");
	updateStmt = conn.prepareStatement("UPDATE Test_Cases SET " +
	" best_Res = ?, last_Best_At = ?, " +
	" last_Res = ?, last_Duration = ?, " +
	" stat_Cnt = ?, stat_Avg = ?, " +
	" stat_Min = ?, stat_Max = ? " +
	"WHERE id = ?;");
	insertDetStmt = conn.prepareStatement("INSERT " +
	"INTO Test_Case_Runs (test_Id, run_At, iteration, res, duration) " +
	"VALUES (?, ?, ?, ?, ?);");
	insertEventStmt = conn.prepareStatement("INSERT " +
	"INTO Test_Case_Events (test_Id, run_At, relevance, res, duration) " +
	"VALUES (?, ?, ?, ?, ?);");
	selectAllStmt = conn.prepareStatement("SELECT id, name, " +
	"last_Res, stat_Cnt, " +
	"last_Duration, stat_Avg, stat_Min, stat_Max " +
	"FROM Test_Cases;");

	try {
	// ResultSet res = stmt.executeQuery("PRAGMA CACHE_SIZE;");
	// res.first();
	// System.out.print("CACHE_SIZE = ");
	// System.out.println(res.getString(1));
	// stmt.execute("PRAGMA CACHE_SIZE = 5000;");
	stmt.execute("PRAGMA SYNCHRONOUS = OFF;");
	stmt.execute("PRAGMA temp_store = MEMORY;");
	}
	catch (SQLException e) {
	dbVersion = "";
	}
	stmt.close();
	conn.commit();
	// }
	// catch (Exception e) {
	// conn = null;
	// }
	// return conn != null;
	}

	static void close() {
	try {
	conn.commit();
	conn.close();
	conn = null;
	}
	catch (Exception e) {
	conn = null;
	}
	}
	}