Using drbd for real-time data backup this article is not suitable for use in the production environment. The key lies in a simple understanding of the configuration and working methods of drbd. In this exampleData is stored on two servers and will not be automatically switched when one of them fails (although in some cases there is a faultDrbd automatically switc
If you want to update a list in real time, the traditional approach is to use polling. Take the web as an example, using AJAX to periodically request the server and then get the data displayed on the page. This approach is simple, and the downside is wasting resources.
HTTP1.1 has added support for websocket so that passive displays can be turned into active not
xml| Data | refresh | no refresh
Some time ago wrote several examples about the use of XMLHTTP.
(You can go to http://dev.csdn.net/user/wanghr100 to see some of the previous series on XMLHTTP introduction.)
Recently, the forum is often asked questions about how no refresh, Automatic Update data.
Traditionally, we browse the Web and if we add
Not much nonsense, on the code, front desk:The main use of the dead loop one second to read the JS once to refresh the page (recursive idea) separately to ShowData this div data to refresh, the individual feels that it needs to be optimized. Ask the great God for guidanceBackground main code:1. The naming format for the header is JSON" Application/json ";2. Returns a JSON-stitched string that might later be optimized to write a JSON class to generate
In a JSP page to achieve a two-level drop-down box linkage, real-time reading of database data, this method is very useful, only need to modify a small place can be used. The design of the document, Serch.jsp,main.js,bytetostr.js,
First, let's talk about Main.js, which is JavaScript, which takes note of modifying the JSP page name.
The following are
, client installation rsync,inotify-tools and configuration1. Install rsync and configureYum Install Rsync-yThe client configures Rsync, creates a password file, synchronizes with this file later and does not need to fill in the password:touch/etc/rsync_passwdchmod 600/etc/rsync_passwdecho "123456" >/etc/rsync_passwd(writes the account password of the server user Sandy to the password file)2, install Inotify-tools (because the centos6.6 system has built-in inotify, so there is no need to install
Import react,{component} from ' React 'Import Reactdom from' React-dom 'class Childcounter extends component{render () {return( { This. Props.count} ) }}/** Everyone defaults to some of the steps, easy to see * 1. Default value * 2. Initialization status * 3. hook function * 4. Method function **/class Counter extends component{//Default Property ObjectStatic defaultprops={number:5} constructor (props) {super (props); //get my initial status This. sta
The server webpage we are requesting this time is: Edit_Data.Asp. I will provide the source code of this asp file in this ajax tutorial.In fact, it is easy for you to modify data when you learn how to use ajax to add data! Let's talk about the front-end JavaScript code and the effect of this ajax instance!Copy codeThe Code is as follows:Input No.: Modification co
xml| Data | refresh | No refresh Traditionally, we browsed the Web page if we added the latest data. It can only be displayed when we re requesting a server-side request.
However, for some time-sensitive websites. The traditional approach is not satisfying.
We can get the program to refresh automatically. Request data
Php+mysql+sphinx, the sooner the better, the faster the time.
Do you guys have any suggestions?
10 million data the table contains more than 30 fields, and there are not less than 10 child tables, and the fields that need to be searched are in both the main table and the child table.
The search is fast and the delay is guaranteed to be almost 1 seconds.
High concurrency odds are not too high
Reply co
After the datatable is bound to gridcontrol, after the data in the table is edited, the last row of data is always lost when it is saved. It has been confusing for a long time and is finally solved today. It's actually very simple.
Grid1.focusedview. closeeditor ();Grid1.focusedview. updatecurrentrow ();
Why not use the view name of gridview1 here? Sometimes, w
didn't overwrite the onsaveinstancestate () method, this method automatically saves some data in the activity by default, such as the state and value of the UI control, as long as you need to specify a unique ID for the control. Otherwise, the data for the control does not appear to be saved. So when do you save the Overwrite method?If you need to save additional data
Originally intended to implement such a feature on a Web page: for example, there are multiple buttons on the page, button 1, button 2, button 3, etc.
The response of the button 1 is time-consuming, how can you click on the button 1, do not wait for its response, you can click its
His button, and the button 1 will brush the result after the response is finished?
Think carefully, it is impossible! This requirement is very simple for WinForm programs
DS = new dataset ();SDA. Fill (DS, "student ");// This. Maid = Ds. Tables ["student"];// Bind data to the datagridviewMyinvoke MI = new myinvoke (binddatagridview );This. begininvoke (MI, new object [] {DS });}Catch (exception ex){MessageBox. Show (ex. Message );}Finally{Con. Close ();}}
Private void button#click (Object sender, eventargs E){// Test and add a piece of data to check whether the
The effect is as shown in the figure:
The JS code is as follows:
1 $ (document). Ready (function () {2 highcharts.setoptions ({3 global: {4 useutc:f
Alse 5}, 6 colors: "#08c, #ff5a00". Split (","), 7 symbols: ["Circle", "triangle"]
8}); 9 var options = {One chart: {renderto: ' container ', t ype: ' Spline ', Marginright:10, events: {load:function () {//Set up the updating of the chart each second//var series =
This.series[0]; $.each (this.series, function (IDX, series) {SetInterval (
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