Skip to main content

Home/ Google AppEngine/ Group items tagged link

Rss Feed Group items tagged

Filter: All | Bookmarks | Topics Simple Middle
Esfand S

Using the bulkloader with Java App Engine « Ikai Lan says - 0 views

ikaisays.com/...ulkloader-with-java-app-engine

gaej gae bulkloader java top best appengine bulkloading theone

shared by Esfand S on 28 Sep 10 - Cached
  • I’m trying to use the bulkuploader for a java program but am running into an interesting issue. My PrimaryKey property is a Long, and in java I can explicitly give them id numbers and they show in the data store as “id=xxx”. When I download the data via the appcfg.py I get a reasonably looking data file. If I reupload the same file it actually inserts things into the data store with key “name=xxx” and therefore doubles every one of my entries.
  • create a custom uploader using the file upload example provided on appengine’s java FAQ.
  • App Engine’s datastore is schemaless. That is – it is possible to have Entities of the same Kind with completely different sets of properties. Most of the time, this is a good thing. MySQL, for instance, requires a table lock to do a schema update. By being schema free, migrations can happen lazily, and application developers can check at runtime for whether a Property exists on a given Entity, then create or set the value as needed. But there are times when this isn’t sufficient. One use case is if we want to change a default value on Entities and grandfather older Entities to the new default value, but we also want the default value to possibly be null.
  • ...1 more annotation...
  • I used a combination of uploading entire chunks of my data via FileUpload (see link below), and explicitly creating my Java objects with the keys that I wanted (which were easily implicitly defined by the data format as the first one would be ‘n’ and every object after it was n++). I would then insert the set of objects in bulk. The problem I hit the most was finding the right number of objects per store call. There are specific limits that make this process long and annoying. I ran something locally that would continue trying to upload the chunk of data until it got a good response from the server page. It took me something on the order of 6-8 hours to upload about 1.5M tiny objects. http://code.google.com/appengine/kb/java.html#fileforms
Esfand S

Pagination - Google App Engine | Google Groups - 0 views

groups.google.com/...da1b069ff1454548

appengine datastore pagination tip

shared by Esfand S on 28 Sep 10 - Cached
  • The next problem that arises is that if the database has grown too big, then the csv generation will be slow(as it has to jump a lot of times). So the next idea is , instead of generating all cursors in the main cgi , the main cgi generates only first few set of page links, and then triggers a task queue entry to continue from there. By the time the user would have read the first page and clicks on "next page", the task would have generated few more entries. As the set of cursors for pagination is in memcache, you can use it even in your first page, if you are using AJAX (guessing, not that sure.)
Esfand S

Eclipse, AppEngine, Java. - Google App Engine | Google Groups - 0 views

groups.google.com/...51635bf8cd3d30d8

gae project organization tip appengine

shared by Esfand S on 28 Sep 10 - Cached
  • You create a java project only with the shared files (NOT a GAE project). You DON'T copy any libraries into the lib folder. You should add the required third-party components into your main project. Then you rightclick on the shared project's *source* folder, go to "Build Path -> Remove from build path" item in the context menu. You may, by the way, rename the source folder, so that it has a name different from the default source folder name. Next you rightclick on the main project's folder, go to "Build Path -> Link source".
Esfand S

Does Eclipse upload 3rd-party GWT libraries to GAE? - Stack Overflow - 0 views

stackoverflow.com/...3rd-party-gwt-libraries-to-gae

gae latency performance top best tip appengine

shared by Esfand S on 28 Sep 10 - Cached
  • Cold-start latency is determined by the time it takes to load all the classes needed to handle the request. If you upload a JAR file, but nothing references it, it won't be loaded, and thus won't affect your cold-start latency.
  • Only those jars under WEB-INF/lib will be uploaded to GAE. You can prevent GWT jars from being uploaded by not placing them under WEB-INF/lib, rather by externally linking to them in your project build path.
1 - 7 of 7
Showing 20▼ items per page