I want to log all mqtt messages of the broker. How should I design schema of database. Avoiding dulplicate entries and fast searching -

-

i implementing callback in java store messages in database. have client subscribing '#'. problem when # client disconnects , reconnect adds duplicate entries in database of retained messages. if search previous entries bigger tables expensive in computing power. should allot separate table each sensor or per broker. appreciate if suggest me better designs.

subscribing wildcard single client anti-pattern. reasons are:

  1. wildcard subscribers all messages of mqtt broker. client libraries can't handle load, not when transforming / persisting messages.
  2. if wildcard subscriber dies, will lose messages (unless broker queues endlessly you, doesn't work)
  3. you have single point of failure in system. use mqtt brokers hardened production use. these more robust single point of failures hand-written clients. (you can overcome sip through clustering , load balancing, though).

so solve problem, suggest following:

  • use broker can handle shared subscriptions (like hivemq or messagesight), can balance messages between many clients
  • use custom plugin doing persistence @ broker instead of client.

you can read more topic here: http://www.hivemq.com/blog/mqtt-sql-database


Comments

Post a Comment

Popular posts from this blog

php - Invalid Cofiguration - yii\base\InvalidConfigException - Yii2 -

-
Image
i've installed yii2-user module/dektrium yii2-app-basic application command composer require "dektrium/yii2-user:0.9.*@dev" config/console.php return [ . . 'modules' => [ 'gii' => 'yii\gii\module', 'user' => [ 'class' => 'dektrium\user\module', ], ], . . ] config/web.php 'components' => [ . . /* 'user' => [ 'identityclass' => 'app\models\user', 'enableautologin' => true, ], */ 'modules' => [ 'user' => [ 'class' => 'dektrium\user\module', ], ], . . ] after that, run command $ php yii migrate/up --migrationpath=@vendor/dektrium/yii2-user/migrations updating database schema . but, when run http://localhost/mylawsuit/yii/web/index.php?r=u
Read more

How to show in django cms breadcrumbs full path? -

-
need advice - how show in breadcrumbs whole path article or page? i've got code: {% ance in ancestors %} <li> {% if not forloop.last %} <a href="{{ ance.get_absolute_url }}">{{ ance.get_menu_title }}</a> {% else %} <span class="active">{{ ance.get_menu_title }}</span> {% endif %} </li> {% endfor %} but shows "home" , current page. how modify show whole path in breadcrumbs? i've found in file menu_tags.py code calls ancestors. @ least there class showbreadcrumbs: class showbreadcrumb(inclusiontag): """ shows breadcrumb node has same url current request - start level: after level should breadcrumb start? 0=home - template: template used render breadcrumb """ name = 'show_breadcrumb' template = 'menu/dummy.html' options = options( argument('start_level', default=0, require
Read more

ruby on rails - npm error: tunneling socket could not be established, cause=connect ETIMEDOUT -

-
i have app uses rails framework , implements angularjs part of front end. i have pushed heroku , have heroku toolbelt installed, when try migrate db using "heroku run rake db:migrate" receive following error(s): installing core plugins heroku-cli-addons, heroku-apps, heroku-fork, heroku-git, heroku-local, heroku-run, heroku-status... error installing package. try running again gode_debug=info see more output. ! `run` not heroku command. ! perhaps meant `-h`, `2fa`, `auth`, `join`, `open`, `orgs`, `pg`, `ps` or `rake`. ! see `heroku help` list of available commands. i run command "gode_debug=info heroku run rake db:migrate" , receive error: npm err! darwin 14.5.0 npm err! argv "/users/christopher_pelnar/.heroku/node-v4.2.1-darwin-x64/bin/node" "/users/christopher_pelnar/.heroku/node-v4.2.1-darwin-x64/lib/node_modules/npm/cli.js" "install" "heroku-cli-addons" "heroku-apps" "heroku-fork
Read more