mysql - Best Practice for synchronized jobs in Application clusters -

-

we have got 3 rest-applications within cluster. each application server can receive requests "outside".

now got timed events, analysing database , add/remove rows database, send emails, etc.

the problem is, each application server start timed events , happens 2 application server starting analysing job @ same time.

we got sql table in back.

our idea lock table within sql database, when starting job. if table locked, exit job, because other application started analyse.

what's practice insert kind of semaphore ?

any ideas ?

don't use semaphores, on complicating things, use message queueing, queue tasks , them executed in row.

make 1 separate node/process/child_process consume queue , task done.


Comments

Post a Comment

Popular posts from this blog

javascript - oscilloscope of speaker input stops rendering after a few seconds -

-
the following script reads audio user's microphone , renders oscilloscope on html canvas. the source taken example of mozilla developer network: visualizations web audio api and here fiddle: http://jsfiddle.net/b7j8pktp/ mozgetusermedia (note: code has no fork mechanism different browsers: works firefox) it works fine few seconds , stops rendering. whereas works totally stable: http://mdn.github.io/voice-change-o-matic/ the problem can reduced following code. microphone activation icon (next the address bar in firefox) disappears after 5 seconds: navigator.mozgetusermedia({audio: true}, function() {}, function() {} ); ( http://jsfiddle.net/b7j8pktp/2/ ) this known bug in firefox. take stream getusermedia call , hook window so: navigator.mozgetusermedia({audio: true}, function(stream) { window.stream = stream; // rest of code }, function err() { // handle error }); hopefully can fixed soon. problem we're f
Read more

javascript - gulp-nodemon - nodejs restart after file change - Error: listen EADDRINUSE events.js:85 -

-
i'm running nodejs 0.12.3 - gulp 3.10.8 , gulp-nodemon 2.0.3. gulpfile.js : gulp.task('serve', ['build'], function() { gulp.start('fb-flo'); nodemon({ script: paths.server, env: { 'node_env': 'development' }, // env: { 'node_env': 'production' }, execmap: { 'js': 'node_modules/babel/bin/babel-node --stage 1' //es7 cote server }, delay: '0ms', watch: ['src/shared/', 'src/server/'], ignore: ['src/shared/components'], tasks: function (changedfiles) { var tasks = []; changedfiles.foreach(function (file) { if (path.extname(file) === '.jsx' && !~tasks.indexof('bundlejs')) tasks.push('bundlejs'); if (path.extname(file) === '.less' && !~tasks.indexof('compileless')) tasks.push('compileless'); }); return tasks; }
Read more

Fatal Python error: Py_Initialize: unable to load the file system codec. ImportError: No module named 'encodings' -

-
i trying make simple python program opening list of webpages user manually download reports site. don't have previous experience preparing exe files.. , i'm in learning process python coding. of done on windows 7 x64 this python code: #!c:/python34/python.exe -u splinter import * import time import os import csv #---------------------------------- raporty = [] open('../raporty.csv', newline='') csvfile: contents = csv.reader(csvfile, delimiter=' ', quotechar='|') row in contents: r = ', '.join(row) r = r.replace(',','') raporty.append(r) #--not implemented yet zmienne = [] open('../zmienne.csv', newline='') csvfile: contents = csv.reader(csvfile, delimiter=' ', quotechar='|') row in contents: r = ', '.join(row) r = r.replace(',','') zmienne.append(r) print("start") browser = browser(
Read more