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我正在嘗試在Java程序中使用SQL數據庫。我製作了一張寬度爲7列，行數爲250萬的表格（我需要構建的下一個表格大約需要2億行）。我有兩個問題：構建SQL表的速度太慢（大約每分鐘2000行），並且搜索數據庫太慢（如果可能，我需要在一秒鐘內找到超過1億行，目前需要一分鐘）。我曾嘗試創建一個csv文件並導入它，但I can't get it to work。Java SQL優化
我在我的電腦上使用xampp和phpMyAdmin（i5 + 6gb ram）。我有三個測試方法：createTable（），writeSQL（）和searchSQL（）。
CREATETABLE：
public static void createTable() {
String driverName = "org.gjt.mm.mysql.Driver";
Connection connection = null;
try {
Class.forName(driverName);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String serverName = "localhost";
String mydatabase = "PokerRanks4";
String url = "jdbc:mysql://" + serverName + "/" + mydatabase;
String username = "root";
String password = "";
try {
connection = DriverManager.getConnection(url, username, password);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
///////////////
String table = "CREATE TABLE ranks(deckForm bigint(10) NOT NULL,rank0 int(2) NOT NULL,rank1 int(2) NOT NULL,rank2 int(2) NOT NULL,rank3 int(2) NOT NULL,rank4 int(2) NOT NULL,rank5 int(2) NOT NULL,PRIMARY KEY (deckForm),UNIQUE id (deckForm),KEY id_2 (deckForm))";
try {
Statement st = connection.createStatement();
st.executeUpdate(table);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
///////////////
try {
connection.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
writeSQL（）：
public static void writeSQL() {
String driverName = "org.gjt.mm.mysql.Driver";
Connection connection = null;
try {
Class.forName(driverName);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String serverName = "localhost";
String mydatabase = "PokerRanks4";
String url = "jdbc:mysql://" + serverName + "/" + mydatabase;
String username = "root";
String password = "";
try {
connection = DriverManager.getConnection(url, username, password);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
/////////////// Prepared Statement with Batch
PreparedStatement statement = null;
String sql = "INSERT INTO ranks VALUES (? ,0, 0, 0, 0, 0, 0)";
long start = System.currentTimeMillis();
try {
statement = connection.prepareStatement(sql);
for (int i = 0; i < 100; i++) {
for (int j = 0; j < 100; j++) {
statement.setLong(1, (i*100 + j));
statement.addBatch();
}
System.out.println(i);
statement.executeBatch();
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (statement != null) {
try {
statement.close();
} catch (SQLException e) {
} // nothing we can do
}
if (connection != null) {
try {
connection.close();
} catch (SQLException e) {
} // nothing we can do
}
}
System.out.println("Total Time: " + (System.currentTimeMillis() - start)/1000);
///////////////
}
searchSQL（）：
public static void searchSQL() {
String driverName = "org.gjt.mm.mysql.Driver";
Connection connection = null;
try {
Class.forName(driverName);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String serverName = "localhost";
String mydatabase = "PokerRanks2";
String url = "jdbc:mysql://" + serverName + "/" + mydatabase;
String username = "root";
String password = "";
try {
connection = DriverManager.getConnection(url, username, password);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
/////////////// Option 1, Prepared Statement
ResultSet rs = null;
PreparedStatement pstmt = null;
String query = "SELECT rank0, rank1, rank2, rank3, rank4, rank5 FROM ranks WHERE deckForm = ?";
long start = System.currentTimeMillis();
try {
pstmt = connection.prepareStatement(query);
for (int i = 0; i < 100000; i++) {
pstmt.setLong(1, 1423354957);
rs = pstmt.executeQuery();
while (rs.next()) {
int[] arr = {rs.getInt(1), rs.getInt(2), rs.getInt(3), rs.getInt(4), rs.getInt(5), rs.getInt(6)};
}
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("Total Time: " + (System.currentTimeMillis() - start)/1000);
///////////////
/*
/////////////// Option 2
Statement st = null;
long start = System.currentTimeMillis();
try {
st = connection.createStatement();
ResultSet rs = null;
long deckForm = 1012213456;
for (int i = 0; i < 100000; i++) {
rs = st.executeQuery("SELECT rank0, rank1, rank2, rank3, rank4, rank5 FROM ranks WHERE deckForm = " + deckForm);
while (rs.next()) {
int[] arr = {rs.getInt(1), rs.getInt(2), rs.getInt(3), rs.getInt(4), rs.getInt(5), rs.getInt(6)};
}
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("Total Time: " + (System.currentTimeMillis() - start)/1000);
///////////////
*/
try {
connection.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
對不起這是這麼長時間。我嘗試了所有我能想到的方法來讓這個更快，但我無法弄清楚。有什麼建議麼？
哪個RDBMS？哪個版本？你的桌子上是否有任何索引？查詢優化器告訴你關於'select'語句的是什麼？ – 2012-06-07 22:39:47