[yeputons]

In the beginning of the post you mention that you need to collect updates from all delta layers until you hit an image layer. Does that mean you have to make a O(log n) query once again every time you hit a delta layer? Is that a slowdown?

[bean_salad_123]

That's right. At the moment it's at most 4 different queries per GetPage request, so not the end of the world. It might grow to 40 soon for reasons*

*reasons: We're probably gonna take less image layers, and rely more on partial image layers, or page images inside delta layers