I have a rails application on a shared server that also has a decently sized database, which is still growing, behind it. The application takes a long time to start/load the homepage, about 20-30 seconds for me, although some people report waiting up to several minutes.
Is there a way to flash a notice that informs people that the database may take several minutes to load while they are waiting?
It's hard to say based on your question, since we don't know exactly what your home page is showing or how it's displaying it, but assuming you are referring to an AJAX (based on the tag) call that is retrieving something from the database to be displayed on your homepage, there are a few things you can try:
Paginate the items. Is whatever you're loading a long list of items? If so, only retrieve a few at once, and let the user decide if they want to see more.
Load the rest of the page (header, footer, navigation bar, etc), and then place a loading gif spinner in the area where the content is to be loaded. If you use a javascript library like jQuery this is pretty trivial, and there are a ton of tutorials out there for it. Here is a good site for free loading indicators: http://ajaxload.info/. What you'll want to do is make the AJAX call and use your javascript library to set the loading image. Then, in the success callback for your ajax call, hide the spinner and show the content.
Load one item at a time. Make a separate ajax call for each item you're going to load, so that the user sees them coming in. This will probably end up taking longer overall (you're hitting the database more often), but the visual may be a nice psychological hack.
Look at how your database queries are set up. Are you getting everything you need in one find? That's the best way to do it, as every time you have to make another trip to the database you're increasing the wait time.
Other than that the best thing you can do is get better hardware if possible, maybe look into a VPS like linode.com.
Related
I've built a Rails app, basically a CRUD app for memos/notes.
A notes title must be unique. If a user enters a name already taken a warning message is shown prompting them to chose another.
My question is how to make this latency for this feedback as close to zero as possible. When creating a note little UX speed bumps like this will get annoying for user quickly.
Of course the main bottleneck is the network. Inspired by Meteor (and mini-mongo) I was thinking some kind of local storage could be a solution?
I.E. When app first loads, send ALL JSON to the client with ALL note titles. The app (front end is Angular JS) could check LocalStorage (or App Cache, Web SQL?) instead of incurring a network round trip. The feedback would be instant.
I've used LocalStorage in the past to augment an app, but in the scenario it'd really seriously depend on it. I'm not sure how confident I'd be building on something that user might not have. Also as the number of user Notes/Memos I have doubts how feasible it is to send a JSON object down the wire with ALL the note titles. That might get pretty big. On the other hand MeteorJS seems to do this with no probs.
Has anyone done something similar or have any pointers? Thanks!
I don't know how Meteor works here, but you're right that storing all note titles in localStorage is not a good idea. Actually, you don't need localStorage here, you can just put it in a JS array, because you need this data only once (when checking new note title).
I think, there could be 2 possible solutions:
You can change your business requirements and allow non-unique title. Is there really a necessity for titles to be unique?
You can verify note title when user submits form. In this case you can provide suggestions for users, so they not spend time guessing vacant title.
Or, if titles must be unique only within a user (two users can have same title for their notes), you can really load all note titles in JS array and check uniqueness while users types in a title.
Or you can send an AJAX request checking title uniqueness as soon as user finished typing the title. In this case you can win some seconds.
Or you can send an AJAX request as soon as user typed in 3 symbols. The request will return all titles that begin with these 3 symbols, so you don't need to load all the titles.
I have an rails application with a huge database (hundreds of gigabytes) that has a lot of different options what to do with the data. In some cases, like changing data, this can be done in a background task I do with Sidekiq. But in other cases, like viewing data with a lot of rows and columns or complex SQL queries, the process of getting the data takes quite long.
What I want to do, is show the user that something is happening when he clicks a link. Like the progress bar many browsers have, but more obvious, so even users not used to working with browsers should see that something is happening and loading.
The question is how to do this. I already tried different options with AJAX and jQuery but most of the times I can only do this for certain actions, but basically I want to do it for the whole application. So every time the user sends a request to load a new page, I want to immediately show him, that something is happening.
The closest I came was a Javascript, that was always triggered. The problem was that it literally happened every time and forced to reload the page. This means when I toggled an element it showed the progress bar and then reloaded the page.
In essence, what I'm looking for:
My application runs on Ruby and Rails 4 and every time a new page is loaded I want the user to show that his request is being processed, so even if the request takes a couple of seconds, the user won't get nervous because he knows that something is happening.
I would really appreciate any help for finding a solution, because I can't seem to find any...
You should use a javascript animation to show to the user that something is happening.
For example : http://ricostacruz.com/nprogress/
Short version: Is there a callback when the rails view is finished rendering?
Longer explanation of my actual problem:
I have this issue where I want to generate a history-object because of some APIs I'm using. So I will be appending to this history object possibly several times before saving it. I know that I can safely save it when the view is rendered, because then there will not be any more calls to the APIs.
After quite a while of googling I can still not find any way of doing this. Is my intended approach the right one, to get a callback from the renderer that says "now everything is rendered. Go ahead and save", or should I do it in a different way?
Does such a callback even exist, or do I need to make it myself?
I would lean towards suggesting that you shouldn't be leaving functionality until after the page has rendered - you should really have completed any API calls in the controller before you start outputting the page. However, if you really must do this you can use javascript to fire off a function (such as an ajax request to an action) after a page has finished rendering.
http://api.jquery.com/ready/ should give you a good starting point!
I've googled some tutorials, browsed some SO answers, and was unable to find a recipe for my problem.
I'm writing a web site which is supposed to display almost realtime stock chart.
Data is stored in constantly updating MySQL database, I wrote a find_by_sql query code which fetches all the data I need to get my chart drawn. Everything is ok, except performance - it takes from one second to one minute for different queries to fetch all the data from the database, this time includes necessary (My)SQL-server side calculations. This is simply unacceptable.
I got the following idea: if the data is queried from the MySQL server one point a time instead of entire dataset, it takes only about 1-100ms to get an individual point.
I imagine the data fetch process might be browser-driven. After the user presses the button in order to get a chart drawn, controller makes one request to the database and renders, say, a progress bar, say 1% ready. When the browser gets the response, it immediately makes an (ajax) request, and the server fetches the next piece of data and renders "2%".
And so on, until all the data is ready and the server displays the requested chart.
Could this be implemented in rails+js, is there a tutorial for solving a similar problem on the Web? I suppose if the thing is feasible at all, somebody should have already done this before.
I have read several articles about ajax, I believe I do understand general principles, but never did nontrivial ajax programming myself.
Thanks for your time!
You could load the page with a div that displays an animated gif (indicating "working"). Then, use body onload to launch your ajax request and replace the contents of that div.
<body onload="some function call to Ajax.Updater('chart')">
<div id="chart">
<img src="working.gif">
</div>
I'm trying to develop an application which modifies a couple of tasks of the famous Online-TODO List RememberTheMilk (rememberthemilk.com) using the REST API.
Unfortunately the modifying takes a lot of time, so I want to give a feedback to the users.
My idea was just to display a couple of text lines (e.g. modifying task 1 of n...).
Therefore I used the periodically_call_remote on my page and called a which reads a Singleton.
In the request I store the text that should be displayed in the same singleton. But I found out, that once I set up a request, the periodically_call_remote does not update the specified div.
My question to this:
1. is this a good way to implement this behaviour?
2. if it is, how do get the periodically_call_remote to work during a submit?
Using a Singleton is most definitely a bad idea. In an advanced production setup it isn't guaranteed that subsequent requests will go to the same process or to the same machine (and subsequently will have a different Singleton). Plus, if you have many users, I don't even want to think about what'll happen to those poor Singletons.
Does any of this stuff actually need to go through your Rails app? It seems like you can call the RTM API via Javascript from the page the user is on and then update the page when the XHR request is complete.