Multiple Threads Not Inserting Everything Into MySQL
Jun 19, 2014
I am very new to threading. I have a program that calls my api and gets data back in json format. Each request returns a row of data in json format. All together I need to retrieve about 2,000,000 rows a day which means 2,000,000 requests (I understand that this is bad design, but the system was not designed for this purpose it is just what I need to do for the next couple of weeks). When I tried running it on a single thread I was processing about 200 requests a minute which is much too slow. As a result I created 12 threads and I was processing 5500 rows a minutes which was a great improvement.
The problem was only about on average 90% of the rows were inserted into the database as I ran it a few times to make sure. Before each insert printed to a file each URL which was sent and then I checked to see if each insert statement was successful (returned 1 when executed ) and it all seems fine. Every time I run it it inserts about 90% but it does varies and it has never been a consistent number.
Essentially the code starts in main by creating 12 threads. Each thread's creates a run method which calls a new instance of MySQLPopulateHistData and passes a start and end integer which are used in the insert statement for ranges. I have done many system.out.println type testing and can see all the threads do start and all the 12 instances (one instance for each thread) called are executing?
MAIN:
import java.io.IOException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class MainClass {
public static void main(String[] args) {
I'm using this try statement to check for errors in input in my Tic Tac Toe game. The problem I have having is I don't understand why this error is happening. It's preventing my code from compiling. I've tried inserting an else statement and multiple brackets at various places with no success.
Java Code: public void play(){ Scanner input = new Scanner(System.in); int row, col; char currPlayer = 'X';
My multi threaded application processes and loads records into an ECM repository. For reconcliation purposes , I am trying to build an XML format report with the results of the processing per record, while processing is underway per thread. The method below is called from every thread wvery time its ready to append an element to the DOM with the status.
public void writeReportLine(Element rptLine) { // Write output to report file synchronized (XMLReportHandler.class) { reportOutput.getDocumentElement().appendChild(rptLine); } }
After all processing completes, the below method is called only once by every thread to write to the File on the file system:
public void writeToReportFile() { synchronized (XMLReportHandler.class) { try{ //write the content into xml file TransformerFactory transformerFactory = TransformerFactory.newInstance(); Transformer transformer = transformerFactory.newTransformer(); DOMSource source = new DOMSource(reportOutput);
[Code] ....
The problem is that when under load, the threads just seem to hang while the transformer.transform(source, result) call keeps getting executed until there is an interrupt of some sort. I was able to examine a section of what was appended and it was status for records that had finished processing very early in the process based on my application logs. Once an interrupt is recieved , it looks like the threads recover.
Actually, i want to create multiple ball using multithreading.I have created a class 'CreateBall' and this class is making ball and second class 'Balls' is a Panel where the ball is display.But only one ball is being displayed.
Here is my code.......
CreateBall.java import java.awt.*; public class CreateBall implements Runnable { int px,py; int w=20,h=20; Graphics g; public CreateBall(int px,int py)
I have a Swing UI in which on click of Search button, I trigger the Search in 6 different modules in 6 Swing Worker threads. The results are returned by each Swing Worker class to the calling class.
I tried to use the below code to get the values returned from each thread. Now, I want to continue further only after all threads finish their execution. How to achieve this?
thread1.addPropertyChangeListener(new PropertyChangeListener() { public void propertyChange(PropertyChangeEvent evt) { if (StateValue.DONE == thread1.getState()) { try {
[Code] ....
I got several examples where the UI is updated direstly from multiple threads. I want the values to be returned to calling class because of below reasons:
1) When even one worker thread fails for some reason, I dont want to show the any result in the UI 2) Earlier, I was updating the UI in done() of every worker class. But, UI became inconsistent. E.g When one thread is in progress, other threads were completed and updating the UI which I dont want to do.
I have a multithreaded application. I have a Logger class with static methods that I use across threads. Would it behoove me to add the synchronized keyword to the static methods of the Logger class since I use this class statically in different threads?
having trouble trying to understand the insertion and removal of Nodes.
I have to insert a new node at the end of the linked nodes, if i insert by terminal : 1, 2, 3. The printed nodes are going to be in the same order, 1,2, 3.
I have done the exercise, but it only prints the last node created and i dont know where its the problem. We did it before with "insert at the beginning", may be the problem is with the print() method in SimpleList.java, but i dont know how to print "backwards".
This is the code:
Node.java
public class Node { public int infoNodo; public Node next; } SimpleList.java public class SimpleList { private Node head;
I know the below code is supposed to format the FormattedTextField but it doesn't seem to do anything to the form (shown in the picture below). I was wanting, when the form loaded: the text field to look something like this
00/00/2014 - 00:00 am
Where the user is able to
- enter datelike information around the symbol separators ( / or : )
- But where the user could not remove these symbol separators
Code:
package datefield; import javax.swing.JFormattedTextField; import javax.swing.text.DateFormatter; public class NewJFrame extends javax.swing.JFrame { public NewJFrame() { initComponents();
What I'm supposed to do is make a method to insert a set of Tiles to the list,i.e.,a detour(make sure that the inserted detouris compatible with thecurrent path so that the resultingpathdoesnot have any gaps). But I'm confused on how to go about doing it. I was thinking of maybe just adding 1 to the current Node.
import java.io.File; import java.io.FileNotFoundException; import java.util.List; import java.util.Scanner; public class Path { static Tile startTile;
So I'm doing a project for my CS class where we have to create a snowman doing something. My picture is of Vince Young in the 2005 Rose Bowl. I'm trying to make the actual video clip from Youtube (do I need to download it? If so I can do that) appear on the scoreboard, but how.
import java.awt.*; import java.awt.event.*; import java.awt.Font.*; class snowBackground { public static void drawField(Graphics g, Color field)
[code]....
There are 3 other files that make the actual Snowmen.Also, would I need to download the mp3 sound file seperately and play that, or will inserting the video do both?
So I'm doing a project for my CS class where we have to create a snowman doing something. My picture is of Vince Young in the 2005 Rose Bowl. I'm trying to make the actual video clip from Youtube (do I need to download it? If so I can do that) appear on the scoreboard. As of right now, this is my background file:
import java.awt.*; import java.awt.event.*; import java.awt.Font.*; class snowBackground { public static void drawField(Graphics g, Color field) { Color sky = new Color(95,166,243);
[Code]...
and this is the Driver file (not sure if this is necessary):
import java.awt.*; import java.awt.event.*; import java.awt.Font.*; public class SnowDriverWSB { public static void main(String args[]) { GfxApp gfx = new GfxApp(); gfx.setSize(1000,650);
[Code]...
There are 3 other files that make the actual Snowmen. To do this, I need VERY basic steps, as I'm extremely confused and new to Java. Also, would I need to download the mp3 sound file seperately and play that, or will inserting the video do both?
I know that for a binary search tree the insert() method is easy. You just kept comparing the values of the nodes, and you would know whether to go left or right depending on the value of the node.However, I am stumped when trying to figure out how to add a node into a normal binary tree where you just keep adding the nodes to the leftmost side, regardless of value.Here is my attempt at the insert() method:
public class RegularTree extends BinaryTree { public CompleteTree() { super(); }
public void insert(Comparable item) { if(this.isEmpty()) { this.setRoot(new TreeNode(item)); return;
So I am working on a DB homework assignment and I am confused in how to implement a users input into the DB; I have to enter some values into a Table that is filled out by a user. It is a basic program, no GUI needed at this point.
I have written the main part but I don't know how I would get the typed value of the data into the SQL Insert Query.
Here is my code (I have a working Database and table with Java DB)
public class AddPeople { public static void main(String[] args)throws Exception { Scanner kb = new Scanner(System.in); try { Connection conn = DriverManager.getConnection("jdbc:derby:PeopleDB");
I know the below code is supposed to format the FormattedTextField but it doesn't seem to do anything to the form (shown in the picture below). I was wanting, when the form loaded: the text field to look something like this
00/00/2014 - 00:00 am
Where the user is able to
- enter datelike information around the symbol separators ( / or : ) - But where the user could not remove these symbol separators
I'm having a problem implementing double hashing when I insert a value into the table i get this for the output:
Insert []. Is there something I'm doing wrong? I'm not getting any errors
public static int size = 0; public static ArrayList<Integer>[] a; public static void interactiveMode(Scanner input) { int menuChoice = 0; do { System.out.println(" Interactive Mode:");
I'm having a problem with double hashing, its supposed to have the user insert an integer into the table and the integer is hashed into the table by the mod of the size of the table so say for instance table size 10 I insert 89 that inserts into 9 because 89%10=9 then i insert 18 that goes into 8 but then once i insert 69 its supposed to collide with index 9 and then uses 7-(69%7) for prime number double hashing...but it just goes into index 9 instead so in 9 it puts 89,69...there's no errors just the wrong output
System.out.print("Enter size of table: "); int n = input.nextInt(); size=n; a = new ArrayList[size]; for (int i = 0; i < size; i++) { a[i] = new ArrayList<Integer>();
I have an exercise for practicing insertion sorts which asks me to do this:
1) Write an insertion sort in insert the name Sam into the list from names.txt..I know how to write an insertion sort. how to integrate inserting an element into the method at the same time.This is what I have so far.
I need to view, update and insert records through a jsp page.example: Employee details..If we give an admission number of an employee, and if the admission number exists in the database then the details like Name, DOB, DOR, Address, Contact info should be displayed in the appropriate fields.(simply a select query in SQL) . The fields are editable and if we need to make any changes we can update in that details itself. If admission number doesn't exists means we can insert all the details except the admission number and a temporary admission number is generated and displayed. The problem with this is i can't able to revert it to the same page.
public class matrix_mul { static int a[][],b[][],k; public static void main(String o[]) { k=0; a=new int[3][3]; b=new int[3][3];
[Code] ....
Well, this is my code for inserting values in 2D array for matrix & then printing it on Command line but it's show ArrayIndexOutOfBoundExcepton 3 or sometimes 1 (on cmd) ....
I'm new to Java and trying to write code a Java program on Mac OS X using IntelliJ. My program uses the SWT library and contains two class's; the first called "view" and the second called "main". The "view" class defines the SWT objects, extends the "Thread" class and contains a "run" method;
public void run() { initComponents(); while (!display.isDisposed()) { if (!display.readAndDispatch()) {
display.sleep();
[code]....
I searched for a solution and saw that I have to use the "-XstartOnFirstThread" parameter to JVM. I'm trying it with no success.
The company entity contains companyName, Sector and Segment columns. The mapping is 3 entities (Company, Sector, Segment) where Sector and Segment are used to create a company record. Sector has a OneToMany relationship with Segment and with Company. I put the Sector and Segment values into two select menus as use these to create a Sector and Segment reference for the Company table. I'm getting the following exception:
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`testdummy`.`company`, CONSTRAINT `FK_COMPANY_FK_COMPANY_SECTORID` FOREIGN KEY (`FK_COMPANY_SECTORID`) REFERENCES `sectors` (`SECTORID`)) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
I'm thinking that the problem is that since the Segment entity is a child of Sector it must be entered through an instance of Sector. Because it's being entered as a separate value I'm getting this error. The problem is Segment is defined as a Set in the Sector entity and I can't figure out how to declare Segment as an instance using its parent entity (Sector).
My code is as follows, starting with the Sector entity:
@Entity @Table(name = "SECTORSNEW") public class SectorsNew { @Id @GeneratedValue(strategy = GenerationType.AUTO) private int sectorId; private String sectorName; @OneToMany(cascade = CascadeType.PERSIST)
I am having issues insert each line of the simple textfile into a specific varible I want it to go to. For example my text file is ordered like this
Dallas 78 F North, 15 mph dallasimage Denver 29 F South, 10 mph denverimage
and I want Dallas in city variable, 78f in temperature variable, and so on until text ends, at the moment is all goes into city variable, it all prints from there! I tried inserting it into an array but it would read all the lines previous to it in addition to reusing readline and all failed.
import java.io.BufferedReader; import java.io.File; import java.io.FileReader; import java.io.IOException; public class Textreader { public static void main(String[] args) {
I am trying to add rows with List of String converted in Object arrays by Array.asList method, and it is inserting Vectors with nothing inside. I tried addColumn and it works perfectly, but in this case Lists represents rows.
