我一直在對(duì)各種語(yǔ)言的MySQL執(zhí)行性能進(jìn)行一些測(cè)試，以衡量它們的整體執(zhí)行時(shí)間，結(jié)果對(duì)我來(lái)說(shuō)似乎完全不對(duì)勁。測(cè)試的主要目標(biāo)是查看從數(shù)據(jù)庫(kù)表中提取數(shù)據(jù)列表，將該數(shù)據(jù)轉(zhuǎn)儲(chǔ)到對(duì)象數(shù)組中，然后將該數(shù)據(jù)輸出到屏幕上需要多少秒。根據(jù)我得到的數(shù)字，我唯一的假設(shè)是，我一定是在Java和Kotlin中做了一些完全錯(cuò)誤的事情，否則根據(jù)結(jié)果，它們的表現(xiàn)要慢得多。這雖然沒(méi)有意義，因?yàn)樗鼈兌际蔷幾g語(yǔ)言，所以它們的性能應(yīng)該很容易比較，如果不是PHP的性能?，F(xiàn)在我假設(shè)下面的代碼中有一些東西導(dǎo)致執(zhí)行時(shí)間比PHP慢得多，并且很好奇是否有人對(duì)可能發(fā)生的事情有任何輸入，或者Java mysql連接器只是比PHP中的PDO連接器慢得多？PHP： 0.21993803977966Kotlin： 0.783954305爪哇： 0.716218516Java Code Long startTime = System.nanoTime(); Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3321/database?user=root&password=pass"); Statement stmt = conn.createStatement(); StringBuilder stringBuilder = new StringBuilder(); ArrayList<Entity> contacts = new ArrayList<Entity>(); ResultSet rs = stmt.executeQuery( "SELECT * FROM contacts" ); while( rs.next() ){ contacts.add( new Entity( rs.getString("firstname"), rs.getString("lastname") ) ); } for( int i = 0; i < 5; i++ ){ contacts.forEach( contact -> stringBuilder.append("huzzah ").append(contact.getFirstName()).append(" ").append(contact.getLastName()).append("\n\r")); } Long endTime = System.nanoTime(); System.out.print( stringBuilder.toString() ); Long elapsedTime = ( endTime - startTime ); double seconds = (double) elapsedTime / 1_000_000_000.0; System.out.println( "Total Execution Time: " + seconds );網(wǎng)絡(luò)工序代碼<?php$starttime = microtime(true);include_once "entity.php";$dbh = new PDO('mysql:host=127.0.0.1;port=3321;dbname=database', "root", "pass");$query = $dbh->prepare("SELECT * FROM contacts");$query->execute();/** @var Entity[] $entities */$entities = [];while( $row = $query->fetch(PDO::FETCH_ASSOC)){ $entities[] = new Entity( $row['firstname'], $row['lastname']);}$buffer = "";for( $i = 0; $i < 5; $i++ ){ foreach ($entities as $entity) { $buffer .= "huzzah {$entity->getFirstName()} {$entity->getLastName()}\n\r"; }}
2 回答
ibeautiful
TA貢獻(xiàn)1993條經(jīng)驗(yàn) 獲得超6個(gè)贊
在Java中連接比PHP慢得多，所以我在數(shù)據(jù)庫(kù)連接之后指定了開(kāi)始時(shí)間。然而，這并不是故事的全部。編譯器也沒(méi)有像@Thomas建議的那樣優(yōu)化代碼。我創(chuàng)建了該項(xiàng)目的導(dǎo)出JAR并進(jìn)行了一些修改。新時(shí)代更加合理，將Java的執(zhí)行時(shí)間減少到0.228579051
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3321/database?user=root&password=password");
Long startTime = System.nanoTime();
Statement stmt = conn.createStatement();
StringBuilder stringBuilder = new StringBuilder();
ResultSet rs = stmt.executeQuery( "SELECT * FROM contacts" );
ArrayList<Entity> contacts = new ArrayList<Entity>(rs.getRow());
while( rs.next() ){
contacts.add( new Entity( rs.getString("firstname"), rs.getString("lastname") ) );
}
for( int i = 0; i < 5; i++ ){
contacts.forEach( contact -> stringBuilder.append("huzzah ").append(contact.getFirstName()).append(" ").append(contact.getLastName()).append("\n\r"));
}
Long endTime = System.nanoTime();
System.out.print( stringBuilder.toString() );
Long elapsedTime = ( endTime - startTime );
double seconds = (double) elapsedTime / 1_000_000_000.0;
System.out.println( "Total Execution Time: " + seconds );
弒天下
TA貢獻(xiàn)1818條經(jīng)驗(yàn) 獲得超8個(gè)贊
您可以嘗試：
ResultSet rs = stmt.executeQuery( "SELECT * FROM contacts" );
ArrayList<Entity> contacts = new ArrayList<Entity>(rs.getRow());
while( rs.next() ){
contacts.add( new Entity( rs.getString("firstname"), rs.getString("lastname") ) );
}
這將在一次調(diào)用中分配所需的所有存儲(chǔ)，而不是以增量方式為每行添加存儲(chǔ)。
永遠(yuǎn)不要低估php的性能和功能。WEB 的一半是用 php 開(kāi)發(fā)的，這是有原因的。
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