database-connection

问题 I have a rails app hosted with NGINX and Puma. Every 10 hours or so, the app becomes unusable. Whenever a user tries to connect, the following error message is displayed: Error during failsafe response: could not obtain a database connection within 5.000 seconds (waited 5.000 seconds) This continues until the app is restarted. I have read that this is because the database connection pool is full, and so there must be threads being created in the rails app that are not closing their connection

问题 I'm writing an application that has a functions.php file that a javascript file is accessing via Ajax. Currently I have each function connecting to the database, running queries, then closing the database. I know there has to be a more efficient way of doing this. I'd like to only input the database credentials once and then have all the functions use it. Whats the most efficient way to do this? I've read quite a few of the answers here on this topic but they're all different and I'm lost.

问题 M newbie to JMeter, Can we track the active DB connections via Jmeter? Is there any parameter or thing in Jmeter which can do the job easier. Right now I am just monitoring the DB connections via terminal. Is it possible with Jmeter 回答1: Given that your database is MySQL: Download MySQL Connector/J, extract mysql-connector-java-x.x.xx-bin.jar , drop it to /lib folder of your JMeter installation, restart JMeter Add Thread Group to the test plan. Configure it as follows: Number of threads: 1

问题 M newbie to JMeter, Can we track the active DB connections via Jmeter? Is there any parameter or thing in Jmeter which can do the job easier. Right now I am just monitoring the DB connections via terminal. Is it possible with Jmeter 回答1: Given that your database is MySQL: Download MySQL Connector/J, extract mysql-connector-java-x.x.xx-bin.jar , drop it to /lib folder of your JMeter installation, restart JMeter Add Thread Group to the test plan. Configure it as follows: Number of threads: 1

问题 I have some Java/Hibernate code that works just fine on my local machine with the database I have installed. However, I've uploaded the code to the Internet on a Glassfish server and I cannot get it to connect to the database associated with that server. I don't think it's a Java problem. I think it's related to the Hibernate settings, as I felt I had to change the address of the database since the code is no longer talking to the database on my machine. Can anyone helpo me? First, here is

问题 A discussion about Singletons in PHP has me thinking about this issue more and more. Most people instruct that you shouldn't make a bunch of DB connections in one request, and I'm just curious as to what your reasoning is. My first thought is the expense to your script of making that many requests to the DB, but then I counter myself with the question: wouldn't multiple connections make concurrent querying more efficient? How about some answers (with evidence, folks) from some people in the

问题 So I have a question about the ideal setup for an app I am getting ready to build. The app is basically going to be a memorization tool and I already have an sqlite database full of content that I will be using for the app. The user will navigate through the contents of the database(using the uipickerview), and select something for memorization. If that row or cell of data is selected, it is put into a pool or a uitableview that is dedicated to showing which items you have in your "need to

问题 i can connect mysql with java using eclipse in a java application with these statements String unicode = "?useUnicode=yes&characterEncoding=UTF-8"; Class.forName("com.mysql.jdbc.Driver"); con = (Connection) DriverManager.getConnection( "jdbc:mysql://localhost:3306/ams-competation" + unicode, username, password); and it works good but my problem is when i tried to connect to mysql with a server application i got this exception java.lang.ClassNotFoundException: com.mysql.jdbc.Driver what am i

问题 This is something I has been always wonder.... will it? Because whenever I write code to use DB connection, I always somehow have to ensure is closed before process to next piece. But when if the I have a ChildWindow that open a connection in its constructor and not close it until it hits the Save Button or Cancel Button. Then if the whole Application got closed, will the DB connection close instantly? Or it has to wait for the timeout and will close automatically? EDIT: So I am trying to

问题 i am new to eclipse environment. I downloaded eclipse helios and tomcat 6. I configured them properly. Now my job is to create servlet for some sign in form. I have been given some existing servlet file from my company. I just need to modify it. Could anybody tell me how to run my existing servlet file? How to connect the file with my mysql table? 回答1: Steps to create java web application: 1.Create new Dynamic Web Project 2.Copy existing servlet file to src folder 3.Create web.xml file in