I have built a SOLR Index which has the image thumbnail urls that I want to render an image along with the search results. The problem is that those images can run into millions and I think storing the images in index as binary data would make the index humongous.
I am seeking guidance on how to efficiently store those images after rendering them from the URLs , should I use the plain file system and have them rendered by tomcat , or should I use a JCR repository like Apache Jackrabbit ?
Any guidance would be greatly appreciated.
Thank You.
I would evaluate the effective requiriments before finally deciding how to persist the images.
Do you require versioning?
Are you planning to stir eonly the images or additional metadata?
Do you have any requirements in horizontal scaling?
Do you require any image processing or scaling?
Do you need access to the image metatdata?
Do you require additional tooling for managing the images?
Are you willing to invest time in learning an additional technology?
Storing on the file system and making them available by an image sppoler implementation is the most simple way to persist your images.
But if you identify some of the above mentioned requirements (which are typical for a content repo or a dam system), then would end up reinventing the wheel with the filesystem approach.
The other option is using a kind of content repository. A JCR repo like for example Jackrabbit or it's commercial implementation CRX is one option. Alfresco (supports CMIS) would be the another valid.
Features like versioning, post processing (scaling ...), metadata extraction and management belong are supported by both mentioned repository solutions. But this requires you to learn a new technology which can be time consuming. Both mentioned repository technologies can get complex.
If horizontal scaling is a requirement I would consider a commercially supported repository implementations (CRX or Alfresco Enterprise) because the communty releases are lacking this functionality.
Me personally I would really depend any decision on the above mentioned requirements.
I extensively worked with Jackrabbit, CRX and Alfresco CE and EE and personally I would go for the Alfresco as I experienced it to scale better with larger amounts of data.
I'm not aware of a image pooling solution that fits your needs exactly but it shouldn't be to difficult to implement that, apart from the fact that recurring scaling operations may be very resource intensive.
I would go for the following approach if FS is enough for you:
Separate images and thumbnail into two locations.
The images root folder will remain, the thumbnails folder is
temporary.
Create a temporary thumbnail folder for each indexing run.
All thumbnails for that run are stored under that location, scaling
can be achived with i.e ImageMagick.
The temporary thumbnail folder can then easily be dropped as soon as
the next run has been completed.
If you are planning to store millions of images then avoid putting all files in the same directory. Browsing flat hierarchies with two many entries will be a nightmare.
Better create a tree structure by i.e. inverting the current datetime (year/month/day/hour/minute ... 2013/06/01/08/45).
This makes sure that the number of files inside the last folder get's not too big (Alfresco is using the same pattern for storing binary objects on the FS and it has proofen to work nicely).
Related
I have an app to create reports with some data and images (min 1 img, max 6). This reports keeps saved on my app, until user sent it to API (which can be done at the same day that he registered a report, or a week later).
But my question is: What's the proper way to store this images (I'm using Realm), is it saving the path (uri) or a base64 string? My current version keeps the base64 for this images (500 ~~ 800 kb img size), and then after my users send his reports to API, I deleted this base64 hash.
I was developing a way to save the path to the image, and then I display it. But image-picker uri returned is temporary. So to do this, I need to copy this file to another place, then save the path. But doing it, I got (for kind of 2 or 3 days) 2x images stored on phone (using memory).
So before I develop all this stuff, I was wondering, will it (copy image to another path then save path) be more performant that save base64 hash (to store at phone), or it shouldn't make much difference?
I try to avoid text only answers; including code is best practice but the question about storing images comes up frequently and it's not really covered in the documentation so I thought it should be addressed at a high level.
Generally speaking, Realm is not a solution for storing blob type data - images, pdf's etc. There are a number of technical reasons for that but most importantly, an image can go well beyond the capacity of a Realm field. Additionally it can significantly impact performance (especially in a sync'ing use case)
If this is a local only app, storing the images on disk in the device and keep a reference to where they are (their path) stored in Realm. That will enable the app to be fast and responsive with a minimal footprint.
If this is a sync'd solution where you want to share images across devices or with other users, there are several cloud based solutions to accommodate image storage and then store a URL to the image in Realm.
One option is part of the MongoDB family of products (which also includes MongoDB Realm) called GridFS. Another option is a solid product we've leveraged for years is called Firebase Cloud Storage.
Now that I've made those statements, I'll backtrack just a bit and refer you to this article Realm Data and Partitioning Strategy Behind the WildAid O-FISH Mobile Apps which is a fantastic article about implementing Realm in a real-world use application and in particular how to deal with images.
In that article, note they do store the images in Realm for a short time. However, one thing they left out of that (which was revealed in a forum post) is that the images are compressed to ensure they don't go above the Realm field size limit.
I am not totally on board with general use of that technique but it works for that specific use case.
One more note: the image sizes mentioned in the question are pretty small (500 ~~ 800 kb img size) and that's a tiny amount of data which would really not have an impact, so storing them in realm as a data object would work fine. The caveat to that is future expansion; if you decide to later store larger images, it would require a complete re-write of the code; so why not plan for that up front.
I'm starting to work with the Google Tango Tablet, hopefully to create (basic) 2D / 3D maps from scanned areas. But first I would like to read as much about the Tango (sensors / API) as I can, in order to create a plan to be as time efficient as possible.
I instantly noticed the ability to learn areas, which is a very interesting concept, nevertheless I couldn't find anything about these so called Area Description Files (ADF).
I know the ADF files can be geographically referenced, that they contain metadata and an unique UUID. Furthermore I know their basic functionalities, but that's about it.
In some parts of the modules ADF files are referred to as 'maps', in other parts they are just called 'descriptions'.
So what do these files look like? Are they already basic (GRID) (2D) maps, or are they just descriptions?
I know there are people who already extracted the ADF files, so any help would be greatly appreciated!
From Tango ADF Doco
Important: Saved area descriptions do not directly record images or
video of the location, but rather contain descriptions of images of
the environment in a very compressed form. While those descriptions
can’t be directly viewed as images, it is in principle possible to
write an algorithm that can reconstruct a viewable image. Therefore,
you must ask the user for permission before saving any of their
learned areas to the cloud or sharing areas between users to protect
the user's privacy, just as you would treat images and video.
Other than that there doesn't seem to be much info about the file internals - I use a lot of them, but I've never been compelled to look inside - curious yes, but not compelled
Without any direct info from the project Tango folks anything we provide would be merely speculation. I'm with Mark, not much compelling reason to get details. My speculation: probably contains a set of image descriptors, like SIFT, and whatever other known device settings are available, like GPS location, orientation (gravity), time(?), etc.
I got the ADF file, basically coded binaries and seems difficult to decode.
I will be happy to share the file if anyone is still interested.
My app shows a map where locations (or Markers) are dynamically loaded via an ajax (and database) request after every map Bounds changes.
I'm convinced that this solution is not scalable : at the moment, Europe area shows a total of 10 markers.
If the database grows and I display for instance 1000 locations, that means 1000 rows would be returned to the user.
This is not a JS / UI since I use the MarkerCluster plugin and I avoid the redraw of loaded locations's markers.
I made some tweaks :
- Delay the Ajax request thanks to an Idle gmaps event
- Increase the minimal zoom level, so the entire world can't be displayed.
But this is not enough.
There are lots of ways to approach this but I will just put here the two I think are most appropriate from your question.
First is to really control from your web app what information is asked for and when. You could write this all yourself in javascript and implement caching techniques ect. There are a number of libraries out there that do most of this work for you though.
I would recommend one of the following:
OpenGeo SDK
OpenLayers
GeoExt
Leaflet
All of these have ways of controlling local caching, when to get the data and what data is gathered from the server. Most of them can also be extended to add any functionality that is missing. The top two I know support google maps (as well as a number of others) as well.
If you need to add even more control over your data locally you could even look at implementing something like PouchDB. I think this is more suited to mobile applications or instances where the network connection is either really slow or intermittent.
This sort of solution should be able to easily handle 1000's to 10000's of features with 100's of users.
If you are really going to scale up to 100000's to 1000000's of features with 100's to 1000's of users then I would suggest adding a tile server to the soloution above. The tile server will sit between your web application and your data base. Most of them have lots of caching settings and optimistions for dealing with large datasets and pushing them out to a client. Because they push out tiles rather than features the data output remains reasonably constant even as the number of features grow. The OpenGeo SDK and Openlayers libraries I mentioned above can work really well with any of the following tile servers:
GeoServer
Mapserver
MapGuide
Quantum GIS Server
If you are reluctant to do any coding there are some offers that work out of the box for enterprise environments. They are all expensive and from your question I think they are probably not what you are looking for.
On one of the applications that I am writing, I was asked to provide the feature for "pencil and eraser" to allow the user to doodle randomly on a document (for proofreading, note-taking, etc.)
What would be the best way to store such data?
I was thinking of using an image with transparency for each doodle (so that I can also support multiple colors of "doodles") but it seems like it will very quickly make any saved project with doodles grow large in file size.
I am looking if there is a better (existing) alternative (e.g. is there a DoodleXML spec out there?) or just any suggestions.
I think the "DoodleXML" spec you're looking for might just be SVG. Simply save the doodles as a series of lines. You don't need a full SVG engine as long as you're only supporting the subset that you generate in the first place.
I currently build a CMS system that need to save a lot of pictures per article. I have a lot of questions :-)
I need to show the pictures in a few sizes, with or without watermark. In addition I need to have the original picture too, for archive and admin purpose. What that I think to do right now is to save the pictures in the database, in two versions: 1. the original picture, 2. web-optimized version.
It is really convenient way to save all the images in a table. But does it really good idea? Let say that the database will contain a hundred of thousand pictures, the original pictures size is probably around 3MB. so the db can be easily 100TB size.... Is this really good strategy?
On the other hand, I save a smaller version to each picture. This version need to be shown in a few sizes, with and without watermark. Currently I think to do think to this in on each request. the request will have parameters width, and according to this I can decide the size and the watermark. (I'll cache this work of course). Again, Is this a good strategy? do it really gonna work, or this is very expensive extra work?
Is it really better to save this on the db? I mean each request to article, will need around 50 another requests to its images, and each request required open/close connection to the database.
Technologies that I going to use: .net, sql-server 2008, NHibernate.
The best approach would be storing those images in filesystem and ids on database. Because of performance and maintenance reasons. Backing up and restoring would be much easier on filesystem and pushing the DBMS for such a work is not the best idea, you will need to transfer them from db to application and then push to the client. I just believe that's not it's job. Put a lighttpd daemon or something for image hosting and leave it do its job.
But if you like the idea, since you are going with sql server 2008, you can use FILESTREAM to store your images in your tables. Eventually, it will create files in a storage location that you choose and store the binary data in filesystem while providing transactional features and data integrity, it is a big bonus. Take a look at that option. As I remember, that performs good and the actual database will be much compact.
About the dynamic resizing, I say avoid that. Storage is cheaper than CPU time, just create variety of thumbnails and watermarked versions upon upload time and store them once in somewhere then use when required. Do not perform same operations again and again. You may do that at first request to the resized version, this way it will be easier to add new versions or purging the cache periodically to remove unused files. You will also be able to backup just the original versions.
Putting the images in the database has a couple of advantages. ACID tanscations and backup consistency come to mind. If you absolutely need that then put the images in the database. As you pointed out, this comes with a price: you'll need a huge database infrastructure like machines, licenses, operation team. Each image retrieval is a huge DB I/O effort.
A lot of things will be much easier with only storing metadata in the DB and putting the image blobs on a filesystem.
Two approaches to come to a decison:
What is the killer feature you absolutely (absolutely like in "if I don't have that, the whole thing will not work at all") need from the image-in-database approach? If there is one, go for it
Do a back-of-the-napkin business case, calculating the total cost of the image-in-database approach (project efforts, infrastructure, machine, license, operation) and compare that with an image-in-filesystem approach. That should give some hints on how to proceed.