有没有办法加快我的 MySQL 执行时间？
Is there a way to speed up my MySQL execution time?
更新：我删除了重复的连接，将时间减少到 18 秒。其他改进也将不胜感激！
我觉得我有一些巨大的疏忽导致它花费的时间比我在数据库中的极少数项目花费的时间长得多。现在，我的数据库中只有大约 85 个实体，但是 运行 宁我的 Java 程序需要 51 秒。对于 40 个实体，花了 35 秒，很明显我做错了什么。该数据库最终将包含数百万个实体，这将需要数天才能完成一个 运行。谁能告诉我应该做什么优化？请注意，在 MySQL 尤其是 Java MySQL 实施方面，我完全是个初学者，所以请放轻松。
问题代码如下：
public static void SQL() {
int handleqty = -1;
String url = "jdbc:mysql://MYURL:3306/MYDB";
String username = "username";
String password = "password";
try{
Connection conn1 = DriverManager.getConnection(url, username, password);
for(Entry<String, String> entry: passToSQL.entrySet()) {
//System.out.println(entry);
String cardinfo = entry.getValue();
String Handle = cardinfo.split(",")[0];
String Title = cardinfo.split(",")[1];
String Vendor = cardinfo.split(",")[2];
String Tags = cardinfo.split(",")[3];
String Published = cardinfo.split(",")[4];
String Option1Name = cardinfo.split(",")[5];
String Option1Value = cardinfo.split(",")[6];
int VariantGrams = Integer.parseInt(cardinfo.split(",")[7]);
String VariantInventoryTracker = cardinfo.split(",")[8];
String VariantInventoryQty = cardinfo.split(",")[9];
String VariantInventoryPolicy = cardinfo.split(",")[10];
String VariantFufillmentService = cardinfo.split(",")[11];
float VariantPrice = Float.parseFloat(cardinfo.split(",")[12]);
String VariantRequiresShipping = cardinfo.split(",")[13];
String VariantTaxable = cardinfo.split(",")[14];
String ImgSrcfront = cardinfo.split(",")[15];
String ImgSrcback = cardinfo.split(",")[16];
String GiftCard = cardinfo.split(",")[17];
String Status = cardinfo.split(",")[18];
String Description = cardinfo.split(",")[19];
String checkexists = "SELECT EXISTS(SELECT 1 FROM MasterCardRecord WHERE Handle = ? LIMIT 1)";
PreparedStatement statement1 = conn1.prepareStatement(checkexists);
statement1.setString(1, Handle);
ResultSet exists = statement1.executeQuery();
exists.next();
//System.out.println(exists.getString(1));
boolean handleexists = false;
if(exists.getString(1).equals("1")) {
handleexists = true;
//REMOVED: Connection conn2 = DriverManager.getConnection(url, username, password);
String sql2 = "SELECT `Variant Inventory Qty` FROM MasterCardRecord WHERE Handle = ? LIMIT 1";
PreparedStatement getqty = conn1.prepareStatement(sql2);
getqty.setString(1, Handle);
ResultSet handleqtyrs = getqty.executeQuery();
handleqtyrs.next();
handleqty = handleqtyrs.getInt(1);
}
if(exists.getString(1).equals("0")) {
handleexists = false;
}
statement1.close();
// REMOVED: conn1.close();
//NEW CODE --------------------------------------------------------------------------------
if (handleexists == true) {
//REMOVED: Connection connInvUpdate= DriverManager.getConnection(url, username, password);
String InvUpdate = "INSERT INTO InventoryUpdate (Handle, `Variant Inventory Qty`) VALUES (?,?) ON DUPLICATE KEY UPDATE `Variant Inventory Qty` = ?";
PreparedStatement InvStatement = conn1.prepareStatement(InvUpdate);
InvStatement.setString(1,Handle);
InvStatement.setInt(2, handleqty + 1);
InvStatement.setInt(3, handleqty + 1);
int updatedInv = InvStatement.executeUpdate();
//REMOVED: connInvUpdate.close();
InvStatement.close();
}
//-----------------------------------------------------------------------------------------
if(handleexists == false) {
// Handle doesnt exist within database
//REMOVED: Connection conn3 = DriverManager.getConnection(url, username, password);
String sql = "INSERT INTO MasterCardRecord (Handle, Title, Vendor, Tags, Published, Option1Name, Option1Value, VariantGrams, `Variant Inventory Tracker`, `Variant Inventory Qty`, `Variant Inventory Policy`, `Variant Fufillment Service`, `Variant Price`, `Variant Requires Shipping`, `Variant Taxable`, `Img Src(front)`, `Img Src(back)`, `Gift Card`, Status, Description) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)";
PreparedStatement statement2 = conn1.prepareStatement(sql);
statement2.setString(1, Handle);
statement2.setString(2, Title);
statement2.setString(3, Vendor);
statement2.setString(4, Tags);
statement2.setString(5, Published);
statement2.setString(6, Option1Name);
statement2.setString(7, Option1Value);
statement2.setInt(8, VariantGrams);
statement2.setString(9, VariantInventoryTracker);
statement2.setString(10, VariantInventoryQty);
statement2.setString(11, VariantInventoryPolicy);
statement2.setString(12, VariantFufillmentService);
statement2.setFloat(13, VariantPrice);
statement2.setString(14, VariantRequiresShipping);
statement2.setString(15, VariantTaxable);
statement2.setString(16, ImgSrcfront);
statement2.setString(17, ImgSrcback);
statement2.setString(18, GiftCard);
statement2.setString(19, Status);
statement2.setString(20, Description);
int rows = statement2.executeUpdate();
if (rows > 0 && showupdates == true) {
System.out.println("Item Added: " + Handle);
}
statement2.close();
//REMOVED: conn3.close();
// Put into AddNewCards as well, for export and adding ONLY those cards that dont exist yet.
Connection AddNewCardConn = DriverManager.getConnection(url, username, password);
String AddNewCardSQL = "INSERT INTO AddNewCards (Handle, Title, Vendor, Tags, Published, Option1Name, Option1Value, VariantGrams, `Variant Inventory Tracker`, `Variant Inventory Qty`, `Variant Inventory Policy`, `Variant Fufillment Service`, `Variant Price`, `Variant Requires Shipping`, `Variant Taxable`, `Img Src(front)`, `Img Src(back)`, `Gift Card`, Status, Description) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)";
PreparedStatement AddNewCardStatement = conn1.prepareStatement(AddNewCardSQL);
AddNewCardStatement.setString(1, Handle);
AddNewCardStatement.setString(2, Title);
AddNewCardStatement.setString(3, Vendor);
AddNewCardStatement.setString(4, Tags);
AddNewCardStatement.setString(5, Published);
AddNewCardStatement.setString(6, Option1Name);
AddNewCardStatement.setString(7, Option1Value);
AddNewCardStatement.setInt(8, VariantGrams);
AddNewCardStatement.setString(9, VariantInventoryTracker);
AddNewCardStatement.setString(10, VariantInventoryQty);
AddNewCardStatement.setString(11, VariantInventoryPolicy);
AddNewCardStatement.setString(12, VariantFufillmentService);
AddNewCardStatement.setFloat(13, VariantPrice);
AddNewCardStatement.setString(14, VariantRequiresShipping);
AddNewCardStatement.setString(15, VariantTaxable);
AddNewCardStatement.setString(16, ImgSrcfront);
AddNewCardStatement.setString(17, ImgSrcback);
AddNewCardStatement.setString(18, GiftCard);
AddNewCardStatement.setString(19, Status);
AddNewCardStatement.setString(20, Description);
int AddCardRows = AddNewCardStatement.executeUpdate();
AddNewCardStatement.close();
//REMOVED: AddNewCardConn.close();
}
if (handleexists == true) {
// Handle DOES exist within database
//REMOVED: Connection conn3 = DriverManager.getConnection(url, username, password);
String sql = "UPDATE MasterCardRecord SET `Variant Inventory Qty` = ? WHERE Handle = ?";
PreparedStatement statement2 = conn3.prepareStatement(sql);
statement2.setInt(1,handleqty + 1);
statement2.setString(2, Handle);
int rows = statement2.executeUpdate();
if (rows > 0 && showupdates == true) {
System.out.println("Inventory of: " + Handle + "has been updated from " + handleqty + " to %d".formatted(handleqty + 1));
}
statement2.close();
//REMOVED: conn3.close();
}
}
}
catch(Exception e){
System.out.println("Database connection failed!\n" + e);
}
}
//ADDED:
conn1.close();
}
此代码的目的是从 CSV 文件收集的地图中获取一些数据，然后遍历该地图并将数据输入 3 个不同的 tables。
- MasterCardRecord：这个 table 包含每张卡及其总数量和其他值
- AddNewCards：此 table 仅包含新卡片的信息，以允许将新卡片导入到另一个网站中
- 库存更新：此 table 包含数据库中已有卡片的句柄和数量，以便快速更新这些卡片的数量
我试图弄清楚这个问题，但如果需要更多信息，这里是完整代码的 pastebin：https://pastebin.com/TQ54f6gB
数据库结构图片：
- https://i.imgur.com/YJKHEz7.png
- https://i.imgur.com/OmIYSh0.png
- https://i.imgur.com/iqbWHbc.png
- https://i.imgur.com/tv2gKMP.png
应要求，照片的文字格式如下：
CREATE TABLE `AddNewCards` (
`Handle` varchar(255) NOT NULL,
`Title` varchar(255) NOT NULL,
`Vendor` varchar(45) DEFAULT 'the10thinningva.com',
`Tags` varchar(255) DEFAULT NULL,
`Published` varchar(5) DEFAULT 'FALSE',
`Option1Name` varchar(45) DEFAULT 'Title',
`Option1Value` varchar(45) DEFAULT 'Default Title',
`VariantGrams` decimal(4,0) DEFAULT '45',
`Variant Inventory Tracker` varchar(45) DEFAULT 'shopify',
`Variant Inventory Qty` int DEFAULT '1',
`Variant Inventory Policy` varchar(45) DEFAULT 'deny',
`Variant Fufillment Service` varchar(45) DEFAULT 'manual',
`Variant Price` decimal(5,2) NOT NULL,
`Variant Requires Shipping` varchar(5) DEFAULT 'TRUE',
`Variant Taxable` varchar(5) DEFAULT 'TRUE',
`Img Src(front)` varchar(255) DEFAULT NULL,
`Img Src(back)` varchar(255) DEFAULT NULL,
`Gift Card` varchar(5) DEFAULT 'FALSE',
`Status` varchar(45) DEFAULT 'active',
`Description` varchar(255) DEFAULT NULL,
PRIMARY KEY (`Handle`),
UNIQUE KEY `handle_UNIQUE` (`Handle`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
CREATE TABLE `InventoryUpdate` (
`Handle` varchar(255) NOT NULL,
`Variant Inventory Qty` int NOT NULL,
PRIMARY KEY (`Handle`),
UNIQUE KEY `Handle_UNIQUE` (`Handle`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
CREATE TABLE `MasterCardRecord` (
`Handle` varchar(255) NOT NULL,
`Title` varchar(255) NOT NULL,
`Vendor` varchar(45) DEFAULT 'the10thinningva.com',
`Tags` varchar(255) DEFAULT NULL,
`Published` varchar(5) DEFAULT 'FALSE',
`Option1Name` varchar(45) DEFAULT 'Title',
`Option1Value` varchar(45) DEFAULT 'Default Title',
`VariantGrams` decimal(4,0) DEFAULT '45',
`Variant Inventory Tracker` varchar(45) DEFAULT 'shopify',
`Variant Inventory Qty` int DEFAULT '1',
`Variant Inventory Policy` varchar(45) DEFAULT 'deny',
`Variant Fufillment Service` varchar(45) DEFAULT 'manual',
`Variant Price` decimal(5,2) NOT NULL,
`Variant Requires Shipping` varchar(5) DEFAULT 'TRUE',
`Variant Taxable` varchar(5) DEFAULT 'TRUE',
`Img Src(front)` varchar(255) DEFAULT NULL,
`Img Src(back)` varchar(255) DEFAULT NULL,
`Gift Card` varchar(5) DEFAULT 'FALSE',
`Status` varchar(45) DEFAULT 'active',
`Description` varchar(255) DEFAULT NULL,
PRIMARY KEY (`Handle`),
UNIQUE KEY `handle_UNIQUE` (`Handle`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
条目示例如下：
'1989-fleer-#nno-california-angels-team-stickers-(one-logo)', '1989 Fleer #NNO California Angels Team Stickers (One Logo)', 'websitelink.com', 'collectable', 'TRUE', 'Title', 'Default Title', '45', 'shopify', '12', 'deny', 'manual', '2.00', 'TRUE', 'TRUE', 'https://linktoajpg_front.jpg', 'https://linktoajpg_back.jpg', 'FALSE', 'active', '1989 Fleer #NNO California Angels Team Stickers (One Logo)'
尝试使用一个连接，打开很多连接会消耗资源，请参阅此post stack post，至少关闭打开的连接。
也尝试将您的代码分成功能，例如更新、检索、添加必须有自己的功能。
编辑：
public static void SQL() {
int handleqty = -1;
String url = "jdbc:mysql://MYURL:3306/MYDB";
String username = "username";
String password = "password";
try{
Connection conn1 = DriverManager.getConnection(url, username, password);
String cardinfo = "";
String Handle = "";
String Title = "";
String Vendor = "";
String Tags = "";
String Published = "";
String Option1Name = "";
String Option1Value = "";
int VariantGrams = "";
String VariantInventoryTracker = "";
String VariantInventoryQty = "";
String VariantInventoryPolicy = "";
String VariantFufillmentService = "";
float VariantPrice = "";
String VariantRequiresShipping = "";
String VariantTaxable = "";
String ImgSrcfront = "";
String ImgSrcback = "";
String GiftCard = "";
String Status = "";
String Description = "";
for(Entry<String, String> entry: passToSQL.entrySet()) {
//System.out.println(entry);
cardinfo = entry.getValue();
Handle = cardinfo.split(",")[0];
Title = cardinfo.split(",")[1];
Vendor = cardinfo.split(",")[2];
Tags = cardinfo.split(",")[3];
Published = cardinfo.split(",")[4];
Option1Name = cardinfo.split(",")[5];
Option1Value = cardinfo.split(",")[6];
VariantGrams = Integer.parseInt(cardinfo.split(",")[7]);
VariantInventoryTracker = cardinfo.split(",")[8];
VariantInventoryQty = cardinfo.split(",")[9];
VariantInventoryPolicy = cardinfo.split(",")[10];
VariantFufillmentService = cardinfo.split(",")[11];
VariantPrice = Float.parseFloat(cardinfo.split(",")[12]);
VariantRequiresShipping = cardinfo.split(",")[13];
VariantTaxable = cardinfo.split(",")[14];
ImgSrcfront = cardinfo.split(",")[15];
ImgSrcback = cardinfo.split(",")[16];
GiftCard = cardinfo.split(",")[17];
Status = cardinfo.split(",")[18];
Description = cardinfo.split(",")[19];
String checkexists = "SELECT EXISTS(SELECT 1 FROM MasterCardRecord WHERE Handle = ? LIMIT 1)";
PreparedStatement statement1 = conn1.prepareStatement(checkexists);
statement1.setString(1, Handle);
ResultSet exists = statement1.executeQuery();
exists.next();
//System.out.println(exists.getString(1));
boolean handleexists = false;
if(exists.getString(1).equals("1")) {
handleexists = true;
//REMOVED: Connection conn2 = DriverManager.getConnection(url, username, password);
String sql2 = "SELECT `Variant Inventory Qty` FROM MasterCardRecord WHERE Handle = ? LIMIT 1";
PreparedStatement getqty = conn1.prepareStatement(sql2);
getqty.setString(1, Handle);
ResultSet handleqtyrs = getqty.executeQuery();
handleqtyrs.next();
handleqty = handleqtyrs.getInt(1);
}
if(exists.getString(1).equals("0")) {
handleexists = false;
}
statement1.close();
// REMOVED: conn1.close();
//NEW CODE --------------------------------------------------------------------------------
if (handleexists == true) {
//REMOVED: Connection connInvUpdate= DriverManager.getConnection(url, username, password);
String InvUpdate = "INSERT INTO InventoryUpdate (Handle, `Variant Inventory Qty`) VALUES (?,?) ON DUPLICATE KEY UPDATE `Variant Inventory Qty` = ?";
PreparedStatement InvStatement = conn1.prepareStatement(InvUpdate);
InvStatement.setString(1,Handle);
InvStatement.setInt(2, handleqty + 1);
InvStatement.setInt(3, handleqty + 1);
int updatedInv = InvStatement.executeUpdate();
//REMOVED: connInvUpdate.close();
InvStatement.close();
}
//-----------------------------------------------------------------------------------------
if(handleexists == false) {
// Handle doesnt exist within database
//REMOVED: Connection conn3 = DriverManager.getConnection(url, username, password);
String sql = "INSERT INTO MasterCardRecord (Handle, Title, Vendor, Tags, Published, Option1Name, Option1Value, VariantGrams, `Variant Inventory Tracker`, `Variant Inventory Qty`, `Variant Inventory Policy`, `Variant Fufillment Service`, `Variant Price`, `Variant Requires Shipping`, `Variant Taxable`, `Img Src(front)`, `Img Src(back)`, `Gift Card`, Status, Description) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)";
PreparedStatement statement2 = conn1.prepareStatement(sql);
statement2.setString(1, Handle);
statement2.setString(2, Title);
statement2.setString(3, Vendor);
statement2.setString(4, Tags);
statement2.setString(5, Published);
statement2.setString(6, Option1Name);
statement2.setString(7, Option1Value);
statement2.setInt(8, VariantGrams);
statement2.setString(9, VariantInventoryTracker);
statement2.setString(10, VariantInventoryQty);
statement2.setString(11, VariantInventoryPolicy);
statement2.setString(12, VariantFufillmentService);
statement2.setFloat(13, VariantPrice);
statement2.setString(14, VariantRequiresShipping);
statement2.setString(15, VariantTaxable);
statement2.setString(16, ImgSrcfront);
statement2.setString(17, ImgSrcback);
statement2.setString(18, GiftCard);
statement2.setString(19, Status);
statement2.setString(20, Description);
int rows = statement2.executeUpdate();
if (rows > 0 && showupdates == true) {
System.out.println("Item Added: " + Handle);
}
statement2.close();
//REMOVED: conn3.close();
// Put into AddNewCards as well, for export and adding ONLY those cards that dont exist yet.
//-----> remove thisConnection AddNewCardConn = DriverManager.getConnection(url, username, password);
String AddNewCardSQL = "INSERT INTO AddNewCards (Handle, Title, Vendor, Tags, Published, Option1Name, Option1Value, VariantGrams, `Variant Inventory Tracker`, `Variant Inventory Qty`, `Variant Inventory Policy`, `Variant Fufillment Service`, `Variant Price`, `Variant Requires Shipping`, `Variant Taxable`, `Img Src(front)`, `Img Src(back)`, `Gift Card`, Status, Description) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)";
PreparedStatement AddNewCardStatement = conn1.prepareStatement(AddNewCardSQL);
AddNewCardStatement.setString(1, Handle);
AddNewCardStatement.setString(2, Title);
AddNewCardStatement.setString(3, Vendor);
AddNewCardStatement.setString(4, Tags);
AddNewCardStatement.setString(5, Published);
AddNewCardStatement.setString(6, Option1Name);
AddNewCardStatement.setString(7, Option1Value);
AddNewCardStatement.setInt(8, VariantGrams);
AddNewCardStatement.setString(9, VariantInventoryTracker);
AddNewCardStatement.setString(10, VariantInventoryQty);
AddNewCardStatement.setString(11, VariantInventoryPolicy);
AddNewCardStatement.setString(12, VariantFufillmentService);
AddNewCardStatement.setFloat(13, VariantPrice);
AddNewCardStatement.setString(14, VariantRequiresShipping);
AddNewCardStatement.setString(15, VariantTaxable);
AddNewCardStatement.setString(16, ImgSrcfront);
AddNewCardStatement.setString(17, ImgSrcback);
AddNewCardStatement.setString(18, GiftCard);
AddNewCardStatement.setString(19, Status);
AddNewCardStatement.setString(20, Description);
int AddCardRows = AddNewCardStatement.executeUpdate();
AddNewCardStatement.close();
//REMOVED: AddNewCardConn.close();
}
if (handleexists == true) {
// Handle DOES exist within database
//REMOVED: Connection conn3 = DriverManager.getConnection(url, username, password);
String sql = "UPDATE MasterCardRecord SET `Variant Inventory Qty` = ? WHERE Handle = ?";
PreparedStatement statement2 = conn3.prepareStatement(sql);
statement2.setInt(1,handleqty + 1);
statement2.setString(2, Handle);
int rows = statement2.executeUpdate();
if (rows > 0 && showupdates == true) {
System.out.println("Inventory of: " + Handle + "has been updated from " + handleqty + " to %d".formatted(handleqty + 1));
}
statement2.close();
//REMOVED: conn3.close();
}
}
}
catch(Exception e){
System.out.println("Database connection failed!\n" + e);
}
}
//ADDED:
conn1.close();
}
PRIMARY KEY(HANDLE) 在 HANDLE 上提供了唯一索引，因此删除
UNIQUE KEY `handle_UNIQUE` (`Handle`)
正在看
SELECT EXISTS(SELECT 1 FROM MasterCardRecord WHERE Handle = ? LIMIT 1)
去掉LIMIT 1。 EXISTS 成功后停止。
正在看
SELECT `Variant Inventory Qty` FROM MasterCardRecord WHERE Handle = ? LIMIT 1
这可以作为存在性检查。也就是看能不能去掉之前的query
没有 ORDER BY 的 LIMIT 会导致得到一些随机结果。如果您不能有多行，那么 LIMIT 会产生误导；如果您关心获得的行中的哪一行，请考虑添加 ORDER BY.
SQL 一次处理多行比从应用程序来回执行要好得多。您的 SELECT 能否获取所有相关行？更好的是，IODKU 能否同时对所有必要的行执行操作？
如果您需要更多帮助，请尝试将代码简化为一个屏幕。我不需要查看所有应用程序代码构建和检查值 -- 除非 代码中确实存在迟缓！
更新：我删除了重复的连接，将时间减少到 18 秒。其他改进也将不胜感激！
我觉得我有一些巨大的疏忽导致它花费的时间比我在数据库中的极少数项目花费的时间长得多。现在，我的数据库中只有大约 85 个实体，但是 运行 宁我的 Java 程序需要 51 秒。对于 40 个实体，花了 35 秒，很明显我做错了什么。该数据库最终将包含数百万个实体，这将需要数天才能完成一个 运行。谁能告诉我应该做什么优化？请注意，在 MySQL 尤其是 Java MySQL 实施方面，我完全是个初学者，所以请放轻松。
问题代码如下：
public static void SQL() {
int handleqty = -1;
String url = "jdbc:mysql://MYURL:3306/MYDB";
String username = "username";
String password = "password";
try{
Connection conn1 = DriverManager.getConnection(url, username, password);
for(Entry<String, String> entry: passToSQL.entrySet()) {
//System.out.println(entry);
String cardinfo = entry.getValue();
String Handle = cardinfo.split(",")[0];
String Title = cardinfo.split(",")[1];
String Vendor = cardinfo.split(",")[2];
String Tags = cardinfo.split(",")[3];
String Published = cardinfo.split(",")[4];
String Option1Name = cardinfo.split(",")[5];
String Option1Value = cardinfo.split(",")[6];
int VariantGrams = Integer.parseInt(cardinfo.split(",")[7]);
String VariantInventoryTracker = cardinfo.split(",")[8];
String VariantInventoryQty = cardinfo.split(",")[9];
String VariantInventoryPolicy = cardinfo.split(",")[10];
String VariantFufillmentService = cardinfo.split(",")[11];
float VariantPrice = Float.parseFloat(cardinfo.split(",")[12]);
String VariantRequiresShipping = cardinfo.split(",")[13];
String VariantTaxable = cardinfo.split(",")[14];
String ImgSrcfront = cardinfo.split(",")[15];
String ImgSrcback = cardinfo.split(",")[16];
String GiftCard = cardinfo.split(",")[17];
String Status = cardinfo.split(",")[18];
String Description = cardinfo.split(",")[19];
String checkexists = "SELECT EXISTS(SELECT 1 FROM MasterCardRecord WHERE Handle = ? LIMIT 1)";
PreparedStatement statement1 = conn1.prepareStatement(checkexists);
statement1.setString(1, Handle);
ResultSet exists = statement1.executeQuery();
exists.next();
//System.out.println(exists.getString(1));
boolean handleexists = false;
if(exists.getString(1).equals("1")) {
handleexists = true;
//REMOVED: Connection conn2 = DriverManager.getConnection(url, username, password);
String sql2 = "SELECT `Variant Inventory Qty` FROM MasterCardRecord WHERE Handle = ? LIMIT 1";
PreparedStatement getqty = conn1.prepareStatement(sql2);
getqty.setString(1, Handle);
ResultSet handleqtyrs = getqty.executeQuery();
handleqtyrs.next();
handleqty = handleqtyrs.getInt(1);
}
if(exists.getString(1).equals("0")) {
handleexists = false;
}
statement1.close();
// REMOVED: conn1.close();
//NEW CODE --------------------------------------------------------------------------------
if (handleexists == true) {
//REMOVED: Connection connInvUpdate= DriverManager.getConnection(url, username, password);
String InvUpdate = "INSERT INTO InventoryUpdate (Handle, `Variant Inventory Qty`) VALUES (?,?) ON DUPLICATE KEY UPDATE `Variant Inventory Qty` = ?";
PreparedStatement InvStatement = conn1.prepareStatement(InvUpdate);
InvStatement.setString(1,Handle);
InvStatement.setInt(2, handleqty + 1);
InvStatement.setInt(3, handleqty + 1);
int updatedInv = InvStatement.executeUpdate();
//REMOVED: connInvUpdate.close();
InvStatement.close();
}
//-----------------------------------------------------------------------------------------
if(handleexists == false) {
// Handle doesnt exist within database
//REMOVED: Connection conn3 = DriverManager.getConnection(url, username, password);
String sql = "INSERT INTO MasterCardRecord (Handle, Title, Vendor, Tags, Published, Option1Name, Option1Value, VariantGrams, `Variant Inventory Tracker`, `Variant Inventory Qty`, `Variant Inventory Policy`, `Variant Fufillment Service`, `Variant Price`, `Variant Requires Shipping`, `Variant Taxable`, `Img Src(front)`, `Img Src(back)`, `Gift Card`, Status, Description) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)";
PreparedStatement statement2 = conn1.prepareStatement(sql);
statement2.setString(1, Handle);
statement2.setString(2, Title);
statement2.setString(3, Vendor);
statement2.setString(4, Tags);
statement2.setString(5, Published);
statement2.setString(6, Option1Name);
statement2.setString(7, Option1Value);
statement2.setInt(8, VariantGrams);
statement2.setString(9, VariantInventoryTracker);
statement2.setString(10, VariantInventoryQty);
statement2.setString(11, VariantInventoryPolicy);
statement2.setString(12, VariantFufillmentService);
statement2.setFloat(13, VariantPrice);
statement2.setString(14, VariantRequiresShipping);
statement2.setString(15, VariantTaxable);
statement2.setString(16, ImgSrcfront);
statement2.setString(17, ImgSrcback);
statement2.setString(18, GiftCard);
statement2.setString(19, Status);
statement2.setString(20, Description);
int rows = statement2.executeUpdate();
if (rows > 0 && showupdates == true) {
System.out.println("Item Added: " + Handle);
}
statement2.close();
//REMOVED: conn3.close();
// Put into AddNewCards as well, for export and adding ONLY those cards that dont exist yet.
Connection AddNewCardConn = DriverManager.getConnection(url, username, password);
String AddNewCardSQL = "INSERT INTO AddNewCards (Handle, Title, Vendor, Tags, Published, Option1Name, Option1Value, VariantGrams, `Variant Inventory Tracker`, `Variant Inventory Qty`, `Variant Inventory Policy`, `Variant Fufillment Service`, `Variant Price`, `Variant Requires Shipping`, `Variant Taxable`, `Img Src(front)`, `Img Src(back)`, `Gift Card`, Status, Description) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)";
PreparedStatement AddNewCardStatement = conn1.prepareStatement(AddNewCardSQL);
AddNewCardStatement.setString(1, Handle);
AddNewCardStatement.setString(2, Title);
AddNewCardStatement.setString(3, Vendor);
AddNewCardStatement.setString(4, Tags);
AddNewCardStatement.setString(5, Published);
AddNewCardStatement.setString(6, Option1Name);
AddNewCardStatement.setString(7, Option1Value);
AddNewCardStatement.setInt(8, VariantGrams);
AddNewCardStatement.setString(9, VariantInventoryTracker);
AddNewCardStatement.setString(10, VariantInventoryQty);
AddNewCardStatement.setString(11, VariantInventoryPolicy);
AddNewCardStatement.setString(12, VariantFufillmentService);
AddNewCardStatement.setFloat(13, VariantPrice);
AddNewCardStatement.setString(14, VariantRequiresShipping);
AddNewCardStatement.setString(15, VariantTaxable);
AddNewCardStatement.setString(16, ImgSrcfront);
AddNewCardStatement.setString(17, ImgSrcback);
AddNewCardStatement.setString(18, GiftCard);
AddNewCardStatement.setString(19, Status);
AddNewCardStatement.setString(20, Description);
int AddCardRows = AddNewCardStatement.executeUpdate();
AddNewCardStatement.close();
//REMOVED: AddNewCardConn.close();
}
if (handleexists == true) {
// Handle DOES exist within database
//REMOVED: Connection conn3 = DriverManager.getConnection(url, username, password);
String sql = "UPDATE MasterCardRecord SET `Variant Inventory Qty` = ? WHERE Handle = ?";
PreparedStatement statement2 = conn3.prepareStatement(sql);
statement2.setInt(1,handleqty + 1);
statement2.setString(2, Handle);
int rows = statement2.executeUpdate();
if (rows > 0 && showupdates == true) {
System.out.println("Inventory of: " + Handle + "has been updated from " + handleqty + " to %d".formatted(handleqty + 1));
}
statement2.close();
//REMOVED: conn3.close();
}
}
}
catch(Exception e){
System.out.println("Database connection failed!\n" + e);
}
}
//ADDED:
conn1.close();
}
此代码的目的是从 CSV 文件收集的地图中获取一些数据，然后遍历该地图并将数据输入 3 个不同的 tables。
- MasterCardRecord：这个 table 包含每张卡及其总数量和其他值
- AddNewCards：此 table 仅包含新卡片的信息，以允许将新卡片导入到另一个网站中
- 库存更新：此 table 包含数据库中已有卡片的句柄和数量，以便快速更新这些卡片的数量
我试图弄清楚这个问题，但如果需要更多信息，这里是完整代码的 pastebin：https://pastebin.com/TQ54f6gB
数据库结构图片：
- https://i.imgur.com/YJKHEz7.png
- https://i.imgur.com/OmIYSh0.png
- https://i.imgur.com/iqbWHbc.png
- https://i.imgur.com/tv2gKMP.png
应要求，照片的文字格式如下：
CREATE TABLE `AddNewCards` (
`Handle` varchar(255) NOT NULL,
`Title` varchar(255) NOT NULL,
`Vendor` varchar(45) DEFAULT 'the10thinningva.com',
`Tags` varchar(255) DEFAULT NULL,
`Published` varchar(5) DEFAULT 'FALSE',
`Option1Name` varchar(45) DEFAULT 'Title',
`Option1Value` varchar(45) DEFAULT 'Default Title',
`VariantGrams` decimal(4,0) DEFAULT '45',
`Variant Inventory Tracker` varchar(45) DEFAULT 'shopify',
`Variant Inventory Qty` int DEFAULT '1',
`Variant Inventory Policy` varchar(45) DEFAULT 'deny',
`Variant Fufillment Service` varchar(45) DEFAULT 'manual',
`Variant Price` decimal(5,2) NOT NULL,
`Variant Requires Shipping` varchar(5) DEFAULT 'TRUE',
`Variant Taxable` varchar(5) DEFAULT 'TRUE',
`Img Src(front)` varchar(255) DEFAULT NULL,
`Img Src(back)` varchar(255) DEFAULT NULL,
`Gift Card` varchar(5) DEFAULT 'FALSE',
`Status` varchar(45) DEFAULT 'active',
`Description` varchar(255) DEFAULT NULL,
PRIMARY KEY (`Handle`),
UNIQUE KEY `handle_UNIQUE` (`Handle`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
CREATE TABLE `InventoryUpdate` (
`Handle` varchar(255) NOT NULL,
`Variant Inventory Qty` int NOT NULL,
PRIMARY KEY (`Handle`),
UNIQUE KEY `Handle_UNIQUE` (`Handle`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
CREATE TABLE `MasterCardRecord` (
`Handle` varchar(255) NOT NULL,
`Title` varchar(255) NOT NULL,
`Vendor` varchar(45) DEFAULT 'the10thinningva.com',
`Tags` varchar(255) DEFAULT NULL,
`Published` varchar(5) DEFAULT 'FALSE',
`Option1Name` varchar(45) DEFAULT 'Title',
`Option1Value` varchar(45) DEFAULT 'Default Title',
`VariantGrams` decimal(4,0) DEFAULT '45',
`Variant Inventory Tracker` varchar(45) DEFAULT 'shopify',
`Variant Inventory Qty` int DEFAULT '1',
`Variant Inventory Policy` varchar(45) DEFAULT 'deny',
`Variant Fufillment Service` varchar(45) DEFAULT 'manual',
`Variant Price` decimal(5,2) NOT NULL,
`Variant Requires Shipping` varchar(5) DEFAULT 'TRUE',
`Variant Taxable` varchar(5) DEFAULT 'TRUE',
`Img Src(front)` varchar(255) DEFAULT NULL,
`Img Src(back)` varchar(255) DEFAULT NULL,
`Gift Card` varchar(5) DEFAULT 'FALSE',
`Status` varchar(45) DEFAULT 'active',
`Description` varchar(255) DEFAULT NULL,
PRIMARY KEY (`Handle`),
UNIQUE KEY `handle_UNIQUE` (`Handle`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
条目示例如下：
'1989-fleer-#nno-california-angels-team-stickers-(one-logo)', '1989 Fleer #NNO California Angels Team Stickers (One Logo)', 'websitelink.com', 'collectable', 'TRUE', 'Title', 'Default Title', '45', 'shopify', '12', 'deny', 'manual', '2.00', 'TRUE', 'TRUE', 'https://linktoajpg_front.jpg', 'https://linktoajpg_back.jpg', 'FALSE', 'active', '1989 Fleer #NNO California Angels Team Stickers (One Logo)'
尝试使用一个连接，打开很多连接会消耗资源，请参阅此post stack post，至少关闭打开的连接。
也尝试将您的代码分成功能，例如更新、检索、添加必须有自己的功能。
编辑：
public static void SQL() {
int handleqty = -1;
String url = "jdbc:mysql://MYURL:3306/MYDB";
String username = "username";
String password = "password";
try{
Connection conn1 = DriverManager.getConnection(url, username, password);
String cardinfo = "";
String Handle = "";
String Title = "";
String Vendor = "";
String Tags = "";
String Published = "";
String Option1Name = "";
String Option1Value = "";
int VariantGrams = "";
String VariantInventoryTracker = "";
String VariantInventoryQty = "";
String VariantInventoryPolicy = "";
String VariantFufillmentService = "";
float VariantPrice = "";
String VariantRequiresShipping = "";
String VariantTaxable = "";
String ImgSrcfront = "";
String ImgSrcback = "";
String GiftCard = "";
String Status = "";
String Description = "";
for(Entry<String, String> entry: passToSQL.entrySet()) {
//System.out.println(entry);
cardinfo = entry.getValue();
Handle = cardinfo.split(",")[0];
Title = cardinfo.split(",")[1];
Vendor = cardinfo.split(",")[2];
Tags = cardinfo.split(",")[3];
Published = cardinfo.split(",")[4];
Option1Name = cardinfo.split(",")[5];
Option1Value = cardinfo.split(",")[6];
VariantGrams = Integer.parseInt(cardinfo.split(",")[7]);
VariantInventoryTracker = cardinfo.split(",")[8];
VariantInventoryQty = cardinfo.split(",")[9];
VariantInventoryPolicy = cardinfo.split(",")[10];
VariantFufillmentService = cardinfo.split(",")[11];
VariantPrice = Float.parseFloat(cardinfo.split(",")[12]);
VariantRequiresShipping = cardinfo.split(",")[13];
VariantTaxable = cardinfo.split(",")[14];
ImgSrcfront = cardinfo.split(",")[15];
ImgSrcback = cardinfo.split(",")[16];
GiftCard = cardinfo.split(",")[17];
Status = cardinfo.split(",")[18];
Description = cardinfo.split(",")[19];
String checkexists = "SELECT EXISTS(SELECT 1 FROM MasterCardRecord WHERE Handle = ? LIMIT 1)";
PreparedStatement statement1 = conn1.prepareStatement(checkexists);
statement1.setString(1, Handle);
ResultSet exists = statement1.executeQuery();
exists.next();
//System.out.println(exists.getString(1));
boolean handleexists = false;
if(exists.getString(1).equals("1")) {
handleexists = true;
//REMOVED: Connection conn2 = DriverManager.getConnection(url, username, password);
String sql2 = "SELECT `Variant Inventory Qty` FROM MasterCardRecord WHERE Handle = ? LIMIT 1";
PreparedStatement getqty = conn1.prepareStatement(sql2);
getqty.setString(1, Handle);
ResultSet handleqtyrs = getqty.executeQuery();
handleqtyrs.next();
handleqty = handleqtyrs.getInt(1);
}
if(exists.getString(1).equals("0")) {
handleexists = false;
}
statement1.close();
// REMOVED: conn1.close();
//NEW CODE --------------------------------------------------------------------------------
if (handleexists == true) {
//REMOVED: Connection connInvUpdate= DriverManager.getConnection(url, username, password);
String InvUpdate = "INSERT INTO InventoryUpdate (Handle, `Variant Inventory Qty`) VALUES (?,?) ON DUPLICATE KEY UPDATE `Variant Inventory Qty` = ?";
PreparedStatement InvStatement = conn1.prepareStatement(InvUpdate);
InvStatement.setString(1,Handle);
InvStatement.setInt(2, handleqty + 1);
InvStatement.setInt(3, handleqty + 1);
int updatedInv = InvStatement.executeUpdate();
//REMOVED: connInvUpdate.close();
InvStatement.close();
}
//-----------------------------------------------------------------------------------------
if(handleexists == false) {
// Handle doesnt exist within database
//REMOVED: Connection conn3 = DriverManager.getConnection(url, username, password);
String sql = "INSERT INTO MasterCardRecord (Handle, Title, Vendor, Tags, Published, Option1Name, Option1Value, VariantGrams, `Variant Inventory Tracker`, `Variant Inventory Qty`, `Variant Inventory Policy`, `Variant Fufillment Service`, `Variant Price`, `Variant Requires Shipping`, `Variant Taxable`, `Img Src(front)`, `Img Src(back)`, `Gift Card`, Status, Description) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)";
PreparedStatement statement2 = conn1.prepareStatement(sql);
statement2.setString(1, Handle);
statement2.setString(2, Title);
statement2.setString(3, Vendor);
statement2.setString(4, Tags);
statement2.setString(5, Published);
statement2.setString(6, Option1Name);
statement2.setString(7, Option1Value);
statement2.setInt(8, VariantGrams);
statement2.setString(9, VariantInventoryTracker);
statement2.setString(10, VariantInventoryQty);
statement2.setString(11, VariantInventoryPolicy);
statement2.setString(12, VariantFufillmentService);
statement2.setFloat(13, VariantPrice);
statement2.setString(14, VariantRequiresShipping);
statement2.setString(15, VariantTaxable);
statement2.setString(16, ImgSrcfront);
statement2.setString(17, ImgSrcback);
statement2.setString(18, GiftCard);
statement2.setString(19, Status);
statement2.setString(20, Description);
int rows = statement2.executeUpdate();
if (rows > 0 && showupdates == true) {
System.out.println("Item Added: " + Handle);
}
statement2.close();
//REMOVED: conn3.close();
// Put into AddNewCards as well, for export and adding ONLY those cards that dont exist yet.
//-----> remove thisConnection AddNewCardConn = DriverManager.getConnection(url, username, password);
String AddNewCardSQL = "INSERT INTO AddNewCards (Handle, Title, Vendor, Tags, Published, Option1Name, Option1Value, VariantGrams, `Variant Inventory Tracker`, `Variant Inventory Qty`, `Variant Inventory Policy`, `Variant Fufillment Service`, `Variant Price`, `Variant Requires Shipping`, `Variant Taxable`, `Img Src(front)`, `Img Src(back)`, `Gift Card`, Status, Description) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)";
PreparedStatement AddNewCardStatement = conn1.prepareStatement(AddNewCardSQL);
AddNewCardStatement.setString(1, Handle);
AddNewCardStatement.setString(2, Title);
AddNewCardStatement.setString(3, Vendor);
AddNewCardStatement.setString(4, Tags);
AddNewCardStatement.setString(5, Published);
AddNewCardStatement.setString(6, Option1Name);
AddNewCardStatement.setString(7, Option1Value);
AddNewCardStatement.setInt(8, VariantGrams);
AddNewCardStatement.setString(9, VariantInventoryTracker);
AddNewCardStatement.setString(10, VariantInventoryQty);
AddNewCardStatement.setString(11, VariantInventoryPolicy);
AddNewCardStatement.setString(12, VariantFufillmentService);
AddNewCardStatement.setFloat(13, VariantPrice);
AddNewCardStatement.setString(14, VariantRequiresShipping);
AddNewCardStatement.setString(15, VariantTaxable);
AddNewCardStatement.setString(16, ImgSrcfront);
AddNewCardStatement.setString(17, ImgSrcback);
AddNewCardStatement.setString(18, GiftCard);
AddNewCardStatement.setString(19, Status);
AddNewCardStatement.setString(20, Description);
int AddCardRows = AddNewCardStatement.executeUpdate();
AddNewCardStatement.close();
//REMOVED: AddNewCardConn.close();
}
if (handleexists == true) {
// Handle DOES exist within database
//REMOVED: Connection conn3 = DriverManager.getConnection(url, username, password);
String sql = "UPDATE MasterCardRecord SET `Variant Inventory Qty` = ? WHERE Handle = ?";
PreparedStatement statement2 = conn3.prepareStatement(sql);
statement2.setInt(1,handleqty + 1);
statement2.setString(2, Handle);
int rows = statement2.executeUpdate();
if (rows > 0 && showupdates == true) {
System.out.println("Inventory of: " + Handle + "has been updated from " + handleqty + " to %d".formatted(handleqty + 1));
}
statement2.close();
//REMOVED: conn3.close();
}
}
}
catch(Exception e){
System.out.println("Database connection failed!\n" + e);
}
}
//ADDED:
conn1.close();
}
PRIMARY KEY(HANDLE) 在 HANDLE 上提供了唯一索引，因此删除
UNIQUE KEY `handle_UNIQUE` (`Handle`)
正在看
SELECT EXISTS(SELECT 1 FROM MasterCardRecord WHERE Handle = ? LIMIT 1)
去掉LIMIT 1。 EXISTS 成功后停止。
正在看
SELECT `Variant Inventory Qty` FROM MasterCardRecord WHERE Handle = ? LIMIT 1
这可以作为存在性检查。也就是看能不能去掉之前的query
没有 ORDER BY 的 LIMIT 会导致得到一些随机结果。如果您不能有多行，那么 LIMIT 会产生误导；如果您关心获得的行中的哪一行，请考虑添加 ORDER BY.
SQL 一次处理多行比从应用程序来回执行要好得多。您的 SELECT 能否获取所有相关行？更好的是，IODKU 能否同时对所有必要的行执行操作？
如果您需要更多帮助，请尝试将代码简化为一个屏幕。我不需要查看所有应用程序代码构建和检查值 -- 除非 代码中确实存在迟缓！