I've been thinking about how to monitor the active oracle sessions on the V$session view.
The things i'd like to do are:
Graph (through a simple grafana graph panel) the sum of all active sessions every 5 minutes. I'm already working on a Perl script to do this.
Extract one or more "owners" of the highest number of active sessions on each poll and visualize them as a popup on the graph or in some other way.
I just want to know who is causing the high amount of sessions on the db.
Is it possible to do this? I hope so :D
Thanks in advance!
How many users do you have? If it's less than say 1000 my suggestion would be to have your script report the number of active sessions for each user separately, that way you can easily visualize not only the total active sessions but also the active sessions for each user.
Related
I have a desktop application which has the "Alarm" feature. The way I'm thinking to implement is that when user selects the data and time for alarm it gets stored in the database and my application query the database every second and match the current date and time of the system with all date and time in the database and then notify if matches. I don't think querying the database every second is good. I can't think of any other way around. This application is also going to sync the alarm records across multiple devices so storing in database is a must I guess.
How do typical alarm application work in which we can set multiple alarms ?
-Thank You
Try create server layer on top of database. Query from db alarm time, create class who send notifications to client apps when alarm time is done. Maybe try use Quartz library?
I am using JDeveloper 11.1.2.3.0
I have implemented af:calenar functionality in my application. My calendar is based in a ViewObject that queries a database table with a big number of records (500-1000). Performing the selection through a select query to my database table is very fast, only some ms. The problem is that the time to load of my af:calendar is too long. It requires more than 5 seconds. If I just want to change the month, or the calendar view I have to wait approximately that amount of time. I searched a lot through the net but I found no explanation to this. Can anyone please explain why it takes so long? Has anyone ever faced this issue?
PS: I have tested even with JDeveloper 12 and the problem is identically the same
You should look into the viewobject tuning properties to see how many records you fetch in a single network access, and do the same check for the executable that populates your calendar.
Also try using the HTTP Analyzer to see what network traffic is going on and the ADF Logger to check what SQL is being sent to the DB.
https://blogs.oracle.com/shay/entry/monitoring_adf_pages_round_trips
I'm trying to find a way to access a centralized database for both retrieval and update.
the following is what I'm looking for,
Server 1 has this variable for example
int counter;
Server 2 will be interacting with the user, and will increase the counter whenever the user uses the service, until a certain threshold is reached. when this threshold is reached then server 2 will start rejecting the user access.
Also, the user will be able to use multiple servers (like server 2) from multiple locations and each time the user accesses the access any server the counter will be increased.
I tried google but it's hard to search for something without a name.
One approach to designing this is to do sharding by user - i.e. split the users between your servers depending on the ID of the user. That is, if you have 10 servers, then users with ID's ending with 2 would have all of their data stored on server 2, and so on. This assumes that user ID's are distributed uniformly.
One other approach is to shard the users by location - if you have servers in Asia vs Europe, for example. You'd need a property in the User record that tells you where the user is located; based on that, you'll know which server to route them to.
Ultimately, all of these design options have a concept of "where does the master record for a user reside?" Each of these approaches attempts to definitively answer this question.
A different category of approaches has to do with multi-master replication, which is supported by some database vendors; this approach does not scale as well (i.e. it's hard to get it to scale to 20 servers), but you might want to look into it, too.
I am building a demo for a banking application in App Engine.
I have a Users table and Stocks table.
In order for me to be able to list the "Top Earners" in the application, I save a "Total Amount" field in each User's entry so I will later be able to SELECT it with ORDER BY.
I am running a cron job that runs over the Stocks table and update each user's "Total Amount" in the User's table. The problem is that I often get TIMEOUTS since the Stocks table is pretty big.
Is there anyway to overcome the time limit restriction in App Engine, or is there any workaround for these kind of updates (where you MUST select many entries from a table that result a timeout)?
Joel
The usual way is to split the job into smaller tasks using the task queue.
You have several options, all will involve some form of background processing.
One choice would be to use your cron job to kick off a task which starts as many tasks as needed to summarize your data. Another choice would be to use one of Brett Slatkin's patterns and keep the data updated in (nearly) realtime. Check out his high performance data-pipelines talk for details.
http://code.google.com/events/io/2010/sessions/high-throughput-data-pipelines-appengine.html
You could also check out the mapper api (app engine map reduce) and see if it can do what you need.
http://code.google.com/p/appengine-mapreduce/
I'm developing an app that has to get some information from various sources (APIs and RSS) and display it to the user in near real-time.
What's the best way to get it:
1.Have a cron job to update them all accounts every 12h, and when a user is requesting one, update that account, save it to the DB and show it to the user?
2.Have a cron job to update them all accounts every 6h, and when a user is requesting one, update the account and showing it to the user without saving it to the DB?
What's the best way to get it? What's faster? And what's the most scallable?
12h or 6h, you have to do the math your self, you are the only one to know how many sources, how is your app hosted, what bandwidth you have....
Have a look at http://developmentseed.org/portfolio/managing-news it is drupal based and does what you need (and much more). You can either use it or diving in the code and see how it is done.