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GreatSQL提供了对服务器端预处理语句(Prepared Statements)的支持。预处理语句可以利用了高效的客户机/服务器二进制协议。使用带有参数值占位符的预处理语句有以下好处:
本文编写Java程序,执行常规SQL语句和预处理语句,对比性能差异,量化预处理语句的性能提升。
通过Java程序进行DML操作,每次DML的数量是10万条,每50条一个提交批次。对比执行预处理语句和普通SQL语句,通过执行时间长短,判断执行的性能。
testInsertPerformance
对比 INSERT 性能;testUpdatePerformance
对比 UPDATE 性能;testSelectPerformance
对比 SELECT 性能;testDeletePerformance
对比 DELETE 性能;greatsql> CREATE DATABASE IF NOT EXISTS testdb1;
greatsql> USE testdb1;
greatsql> CREATE TABLE IF NOT EXISTS test_table (
id INT AUTO_INCREMENT PRIMARY KEY,
col1 INT,
col2 VARCHAR(100),
col3 DATETIME
);
Java程序比较容易使用预处理SQL语句,主要有两点:
useServerPrepStmts=true;
conn.prepareStatement
进行预处理;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.sql.Timestamp;
import java.util.Date;
public class SqlPerformanceTest {
private static final String URL = "jdbc:mysql://192.168.134.208:3307/testdb1?useServerPrepStmts=true";
private static final String USER = "testuser";
private static final String PASSWORD = "testpass";
private static final int NUM_ITERATIONS = 100000;
private static final int BATCH_SIZE = 50;
public static void main(String[] args) {
try (Connection conn = DriverManager.getConnection(URL, USER, PASSWORD)) {
// 清空测试表
clearTable(conn);
// 测试 INSERT 操作
testInsertPerformance(conn);
// 测试 UPDATE 操作
testUpdatePerformance(conn);
// 测试 SELECT 操作
testSelectPerformance(conn);
// 测试 DELETE 操作
testDeletePerformance(conn);
} catch (Exception e) {
e.printStackTrace();
}
}
private static void clearTable(Connection conn) throws Exception {
try (Statement stmt = conn.createStatement()) {
stmt.execute("TRUNCATE TABLE test_table");
}
}
private static void testInsertPerformance(Connection conn) throws Exception {
long startTime, endTime;
// 清空测试表
clearTable(conn);
// 普通 SQL 语句
startTime = System.nanoTime();
conn.setAutoCommit(false); // 关闭自动提交
try (Statement stmt = conn.createStatement()) {
for (int i = 1; i <= NUM_ITERATIONS; i++) {
stmt.executeUpdate("INSERT INTO test_table (id, col1, col2, col3) VALUES ("+ i + "," + i + ", 'value" + i + "', '" + new Timestamp(new Date().getTime()) + "')");
if (i % BATCH_SIZE == 0) {
conn.commit(); // 每50条记录提交一次事务
}
}
conn.commit(); // 提交剩余的记录
} finally {
conn.setAutoCommit(true); // 恢复自动提交
}
endTime = System.nanoTime();
System.out.println("INSERT - Statement: " + (endTime - startTime) / 1000000.0 + " ms");
// 清空测试表
clearTable(conn);
// 预处理 SQL 语句
startTime = System.nanoTime();
conn.setAutoCommit(false); // 关闭自动提交
try (PreparedStatement pstmt = conn.prepareStatement("INSERT INTO test_table (id,col1, col2, col3) VALUES (?, ?, ?, ?)")) {
for (int i = 1; i <= NUM_ITERATIONS; i++) {
pstmt.setInt(1, i);
pstmt.setInt(2, i);
pstmt.setString(3, "value" + i);
pstmt.setTimestamp(4, new Timestamp(new Date().getTime()));
pstmt.executeUpdate();
if (i % BATCH_SIZE == 0) {
conn.commit(); // 每50条记录提交一次事务
}
}
conn.commit(); // 提交剩余的记录
} finally {
conn.setAutoCommit(true); // 恢复自动提交
}
endTime = System.nanoTime();
System.out.println("INSERT - PreparedStatement: " + (endTime - startTime) / 1000000.0 + " ms");
}
private static void testUpdatePerformance(Connection conn) throws Exception {
long startTime, endTime;
// 普通 SQL 语句
startTime = System.nanoTime();
conn.setAutoCommit(false); // 关闭自动提交
for (int i = 1; i <= NUM_ITERATIONS; i++) {
try (Statement stmt = conn.createStatement()) {
stmt.executeUpdate("UPDATE test_table SET col1 = " + i + ", col2 = 'value" + i + "', col3 = '" + new Timestamp(new Date().getTime()) + "' WHERE id = " + i);
if (i % BATCH_SIZE == 0) {
conn.commit(); // 每50条记录提交一次事务
}
}
}
conn.commit(); // 提交剩余的记录
endTime = System.nanoTime();
System.out.println("UPDATE - Statement: " + (endTime - startTime) / 1000000.0 + " ms");
// 预处理 SQL 语句
startTime = System.nanoTime();
conn.setAutoCommit(false); // 关闭自动提交
try (PreparedStatement pstmt = conn.prepareStatement("UPDATE test_table SET col1 = ?, col2 = ?, col3 = ? WHERE id = ?")) {
for (int i = 1; i <= NUM_ITERATIONS; i++) {
pstmt.setInt(1, i);
pstmt.setString(2, "value" + i);
pstmt.setTimestamp(3, new Timestamp(new Date().getTime()));
pstmt.setInt(4, i);
pstmt.executeUpdate();
if (i % BATCH_SIZE == 0) {
conn.commit(); // 每50条记录提交一次事务
}
}
conn.commit(); // 提交剩余的记录
} finally {
conn.setAutoCommit(true); // 恢复自动提交
}
endTime = System.nanoTime();
System.out.println("UPDATE - PreparedStatement: " + (endTime - startTime) / 1000000.0 + " ms");
}
private static void testDeletePerformance(Connection conn) throws Exception {
long startTime, endTime;
// 普通 SQL 语句
startTime = System.nanoTime();
conn.setAutoCommit(false); // 关闭自动提交
for (int i = 1; i <= NUM_ITERATIONS/2; i++) {
try (Statement stmt = conn.createStatement()) {
stmt.executeUpdate("DELETE FROM test_table WHERE id = " + i);
if (i % BATCH_SIZE == 0) {
conn.commit(); // 每50条记录提交一次事务
}
}
}
conn.commit(); // 提交剩余的记录
endTime = System.nanoTime();
System.out.println("DELETE - Statement: " + (endTime - startTime) / 1000000.0 + " ms");
// 预处理 SQL 语句
startTime = System.nanoTime();
conn.setAutoCommit(false); // 关闭自动提交
try (PreparedStatement pstmt = conn.prepareStatement("DELETE FROM test_table WHERE id = ?")){
for (int i = NUM_ITERATIONS/2+1; i <= NUM_ITERATIONS; i++) {
pstmt.setInt(1, i);
pstmt.executeUpdate();
if (i % BATCH_SIZE == 0) {
conn.commit(); // 每50条记录提交一次事务
}
}
conn.commit(); // 提交剩余的记录
} finally {
conn.setAutoCommit(true); // 恢复自动提交
}
endTime = System.nanoTime();
System.out.println("DELETE - PreparedStatement: " + (endTime - startTime) / 1000000.0 + " ms");
}
private static void testSelectPerformance(Connection conn) throws Exception {
long startTime, endTime;
// 普通 SQL 语句
startTime = System.nanoTime();
for (int i = 1; i <= NUM_ITERATIONS; i++) {
try (Statement stmt = conn.createStatement()) {
ResultSet rs = stmt.executeQuery("SELECT * FROM test_table WHERE id = " + i);
while (rs.next()) {
// 处理结果集
}
}
}
endTime = System.nanoTime();
System.out.println("SELECT - Statement: " + (endTime - startTime) / 1000000.0 + " ms");
// 预处理 SQL 语句
startTime = System.nanoTime();
try (PreparedStatement pstmt = conn.prepareStatement("SELECT * FROM test_table WHERE id = ?")) {
for (int i = 1; i <= NUM_ITERATIONS; i++) {
pstmt.setInt(1, i);
ResultSet rs = pstmt.executeQuery();
while (rs.next()) {
// 处理结果集
}
}
}
endTime = System.nanoTime();
System.out.println("SELECT - PreparedStatement: " + (endTime - startTime) / 1000000.0 + " ms");
}
}
编译Java程序
javac -cp .:mysql-connector-j-8.0.32.jar SqlPerformanceTest.java
运行Java程序
java -cp .:mysql-connector-j-8.0.32.jar SqlPerformanceTest
$ java -cp .:mysql-connector-j-8.0.32.jar SqlPerformanceTest
INSERT - Statement: 27089.435867 ms
INSERT - PreparedStatement: 24166.424328 ms
UPDATE - Statement: 32034.818767 ms
UPDATE - PreparedStatement: 29688.13851 ms
SELECT - Statement: 23330.719737 ms
SELECT - PreparedStatement: 20430.097589 ms
DELETE - Statement: 14933.753122 ms
DELETE - PreparedStatement: 13325.930952 ms
多运行Java程序,结果接近,按照其中一次进行数据统计:
操作类型 | 常规SQL语句执行时间(ms) | 预处理语句执行时间(ms) | 性能提升(%) |
---|---|---|---|
INSERT | 27089 | 24166 | 10.79 |
UPDATE | 32034 | 29688 | 7.32 |
SELECT | 23330 | 20430 | 12.43 |
DELETE | 14933 | 13325 | 10.77 |
合计 | 97386 | 87609 | 10.04 |
由于预处理语句比常规SQL语句,节省了SQL语句的解析时间,对于重复执行的SQL语句,使用预处理语句,可以明显地提高执行效率,性能提升约10%。
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