The batch size is currently 50, with a note that it's limited because of URL length restrictions. GUIDs can be up to 64 chars long. Philipp's bookmark GUID work will drop that to 12 chars, which should allow us to go north of 200. For mconnor's 17,000 history items, that would drop us from 340 GETs to 85: a far more pleasing number. (Adding a cap of 5,000 records would put the max number of fetches at 25, of course.) mconnor: "let's actually leave the batch size until after b8". See Bug 616265.

Grabbing this one :)

Patch from what I understood the fix to be.

This bug might be misnamed. The constant that's now eligible to change after our GUIDs got shorter is DEFAULT_MOBILE_GUID_FETCH_BATCH_SIZE... and also DEFAULT_GUID_FETCH_BATCH_SIZE. So: * Verify that all of our GUIDs are 12 chars. If so, change the desktop constant to 200. * If it's only some engines (bookmarks and history, say), do as the comment says and override the behavior in those engines. Separately, MOBILE_BATCH_SIZE limits how many records we fetch and process in a normal Sync fetch on mobile, presumably for memory reasons. It doesn't make sense for the GUID fetch batch size to be larger than this value. So, either: * Bump both DEFAULT_MOBILE_GUID_FETCH_BATCH_SIZE and MOBILE_BATCH_SIZE to a number between 50 and 200, or * Leave these two constants alone, so that we only fetch more on desktop.

Comment on attachment 636452 [details] [diff] [review] patch-v1 I think this code is dead, so wontfixing this. Thanks anyway, Nigel!