The first part of this enhancement would be to identify which part contributes to the slow loading of the image in the first place. Is it because a full-size image is being loaded? Or is a thumbnail itself taking several seconds due to some factor?

Actually, peer review becomes slower and slower. After reviewing a few dozen images, it takes several minutes between each review.

Looks like we should generalise this enhancement as "identify and correct slowness issues in peer review", then.

Is this happening because we check if the image has been reviewed already from a database table?

It could be a reason. The matter is that no one is certain about the actual cause of the slowness. Someone would have to figure out the same. If you're interested in doing so, feel free to 🙂

Just a wild guess (I have not checked the code), but if the algorithm is like below, it is no surprise that it becomes slower and slower:

1. Retrieve last 20 uploads, pick a random one and forget the rest.
2. Check whether the user has never reviewed that upload. If yes review it, else go back to step 1.

I'd added that table, so I thought we're reading the db too frequently. But we're seemingly following the same algorithm as Nicolas has mentioned, so it's about frequent network calls too.

Not sure if this is because I'm using a different device, but the app isn't even fetching the very first image for me. I won't term this as slow but rather call it non-functional. Is the MediaWiki API working?

I'm using the version that's available on the Play Store. I'll try prodDebug from the latest main in some time. I'm running the app on API level 34.

I think the API works fine. It loads the image for me but after some delay of few seconds after the title appears.

I'd cleared storage to check if it's happening with a large table. Skipped that image, and others started appearing quickly. Now it's gets stuck on a few pictures, I skip them to review other images.

I do notice the images taking several seconds (5-10 sometimes) to load. It might be because we load a full-sized image rather than a thumbnail. We could explore loading a thumb in the review screen and show the full-sized image on a tap.

In any case, I suppose you should be able to see the full-sized image load properly when you tap on the image.

What I am seeing is that the ReviewActivity runRandomizer() method is getting called many times (in one test, 30+ times), and there are (at worst) a couple of hundred API calls going on until it finds the next image to review. Each API call is taking 150-250ms each, so you can imagine how long it took for some of the slow images to appear!

Thanks Paul for identifying the root cause!

So the task here is to re-implement the way we find the next image to review, using what API calls (for context the feature was implemented during a hackathon). We should probably make 1 API call to retrieve like 50 pictures to review, then cache the results and use them locally as long as they are not over 1 day old.

Hi, I'm also very interested in this issue. Would it be possible to assign it to me? I'd be happy to contribute to it as well.

@amyWenhui It is yours, thanks! :-)