Executing a cassandra insert query through Python multiprocessing queue -


i have cassandra keyspace sujata.i connecting cassandra using python driver cassandra.cluster.the column family of sujata hello. following code:-

from multiprocessing import process,queue cassandra.cluster import cluster import os queue=queue() cluster = cluster(['127.0.0.1']) metadata = cluster.metadata session = cluster.connect("sujata")  def hi():     global session     global queue     while true:         y=queue.get()         if y=="exit":             os._exit(0)             else:             print y             session.execute(y)  if __name__=="__main__":     x=process(target=hi)     x.start()     in xrange(10):         z="insert hello(name) values('" + str(i) + "');"         queue.put(z)         if i==9:             queue.put("exit")     session.cluster.shutdown()     session.shutdown()

in table, have column name want insert value of i.the insert query passed through queue.i able contents of queue.when run above code,the output is:-

insert hello(name) values('0');

the session.execute() not working. unable understand why happening.

i don't have cassandra machine, guess, it'll work once move connection part prcoess-function hi(). like:

def hi():     cluster = cluster(['127.0.0.1'])     metadata = cluster.metadata     session = cluster.connect("sujata")     global queue     while true:         y=queue.get()         if y=="exit":             os._exit(0)             else:             print y             session.execute(y)

don't know why it's behaving this, i've seen global variables behaving oddly new processes.

this not best way guess. because each time it'll connect same database redundant , need closed. hope there might better answer.

edit 1:

i didn't read code properly. using queue. process hi start once , queue being used communicate between processes. connection database once only. don't need database connection in main process. shifting part multiprocess function best way.


Comments

Post a Comment

Popular posts from this blog

How to access a php class file from PHPFox framework into javascript code written in simple HTML file? -

i've website developed using phpfox v3.0.7 . now i'm trying implement 'sse(server sent events)' 1 of php files. reference i'm giving below necessary code part of file. file titled process.class.php , present @ location /var/www/module/notification/include/service/process.class.php present on server having ip http://34.124.40.142/ . <?php /** * [phpfox_header] */ header('content-type: text/event-stream'); header('cache-control: no-cache'); defined('phpfox') or exit('no dice!'); /** * * * @copyright [phpfox_copyright] * @author raymond benc * @package phpfox_service * @version $id: service.class.php 67 2009-01-20 11:32:45z raymond_benc $ */ class notification_service_process extends phpfox_service { /** * class constructor */ public function __construct() { $this->_stable = phpfox::gett('notification'); } public function add($...
Read more

node.js - Using Node without global install -

i'm working on few node & electron (atom shell) projects , i'm curious how them work without user having install node globally. i've seen few applications including node directory in project contains node.exe binary. how go setting node project use binary? edit: thought should add, i've searched everywhere answer this, unrelated results.
Read more

java - JavaScript + Thymeleaf - select onchange -

i have list of objects services in thymeleaf context, , have following @ page: <select id="inputservice" name="idservice" size="1"> <option th:each="service : ${services}" th:text="${service.name}" th:value="${service.idservice}"/> </select> <p id="selectedservicelimits"></p> each object services contains fields minamount , maxamount . how can print p element these 2 fields of selected service in select javascript? , how can print these 2 fields of option selected when document ready? thanks! <script th:inline="javascript"> /*<![cdata[*/ function showlimits() { var services = /*[[${services}]]*/ null; var selectedindex = $("#inputservice option:selected").index(); var service = services[selectedindex]; $("#amountlimits").text("Ми...
Read more