python - Best practices for monitoring database dependent events -


what best method/approach creating python script dependent on information in database. example:

data being added db. if standard deviation based on column "a" goes above 1, 1.5 or 2, based on user preferences notified. if user has setting set @ 1.5 notified if st.dev above 1.5.

pushing info user not in question, how optimally monitor database updates is.

so far thought of 3 ways:

  1. triggers in mysql, problem here not want leave calculations in mysql. not efficient solution, imagine
  2. create script , run crontab queries data , checks parameters , against user preferences.
  3. creating artificial crontab while true: , sleep combination

any other more optimal or out of box solution missing?

i have not done in mysql, triggers plenty optimized in oracle things. expect mysql similar. if require running calculation every update, trigger fastest method, , guaranteed method date.

i suppose if used external script, run every few minutes? going faster running trigger on every update nature, mysql has time based triggers http://dev.mysql.com/doc/refman/5.1/en/events.html

with trigger, compiled sql trigger stay in database instance's memory likely. compiled sql plenty fast.

i think it's cleaner have sort of thing done triggers, rather maintaining external scripts. opinion though.

if data large mess around moving average formulas, , possibly reduce total number of calculations. seems possible, don't have math background that.

in summary, easy throw sample table , test trigger. give try, think you'll find suites performance needs. if doesn't i'de interested in seeing results.


Comments

Post a Comment

Popular posts from this blog

android - Get AccessToken using signpost OAuth without opening a browser (Two legged Oauth) -

i using signpost oauth access data magento server. have read various tutorials on same , reach point open browser user can enter credentials. however, per requirement have automate part. hence, user should not browser page. have set-up done on server side ( magento ), hit url , returned call page. same through program in android. i have tried below, consumer = new commonshttpoauthconsumer(key, secret); provider = new commonshttpoauthprovider(oauth_init_url,access_token_url, authorize_url); try { provider.retrieverequesttoken(consumer, oauth.out_of_band); log.d("tokens" , consumer.gettoken() + " -- " + consumer.gettokensecret()); } and request tokens. dont know how bypass next step. tried directly accessing accesstoken (stupid of me) provider.retrieveaccesstoken(consumer, "mycallback://callback"); no luck, ends in oauth.signpost.exception.oauthnotauthorizedexception: authorization failed (server replied 401). ...
Read more

org.mockito.exceptions.misusing.InvalidUseOfMatchersException: mockito -

getting error org.mockito.exceptions.misusing.invaliduseofmatchersexception: invalid use of argument matchers! 1 matchers expected, 2 recorded. exception may occur if matchers combined raw values: //incorrect: somemethod(anyobject(), "raw string"); when using matchers, arguments have provided matchers. example: //correct: somemethod(anyobject(), eq("string matcher")); at when( getprogramservice .callservice(any(getprogramtype.class))) .thenreturn(jaxbresponse); please explain error , possible resolution the code posted looks fine; don't see problem it. code before or above causing exception. key here: invalid use of argument matchers! 1 matchers expected, 2 recorded. any , used above, doesn't return "special kind of null" or "special kind of getprogramtype"; don't exist. instead, returns null , side effect puts matcher on stack. whe...
Read more

google shop client API returns 400 bad request error while adding an item -

i'm working on solution add items in google shopping market java application. following tutorial real mess because of missing classes of laste release, after setting 1.5-beta maven managed make base example typecheck correctly classes. still can make simple task of adding 1 item. instead of posting whole code i'm posting part creates product feed. private product createproduct(string id) { product product = new product(); product.title = "red wool sweater"; product.content = new content( "text", "comfortable , soft, sweater keep warm on " + "cold winter nights. red , blue stripes."); product.appcontrol = new appcontrol(); product.appcontrol.addrequireddestination("productads"); product.externalid = id; product.lang = "it"; product.country = "it"; product.condition = "nuovo"; product.price = new price("eu...
Read more