1025071 - Don't index :path field in hpack

Status: RESOLVED FIXED

(Core :: Networking: HTTP, defect)

Description

[u408661]

In order to save space in the table for things that we're more likely to reuse. We should get some real data on this to see if there are any situations in which it makes sense to index :path.

FWIW (which is basically nothing), my totally non-scientific survey of XHRs running on my desktop indicated that there were a lot of paths with long, changes-every-time query strings, so it's not looking good for :path.

Also, according to HTTPArchive data from bigquery, only about 85% of paths are under 100 characters in length, meaning we'll have a decent amount of paths that take up a LOT of space (this is true for both desktop and mobile) causing evictions of things that may be more useful in the future. However, we don't currently have data on reuse of those paths, so it could be that the savings we would get from indexing them might outweigh the need to periodically re-send things like user-agent or accept-language.

It occurs to me just now that we might also want to contemplate not indexing referer, though I (totally non-scientifically) suspect that might have a higher reuse rate than :path.

Comment 1

[u408661]

Attachment: 0001-Bug-1025071-Save-header-table-space-by-not-indexing-path-r-mcmanus.patch

https://tbpl.mozilla.org/?tree=Try&rev=d986ad90c869

Comment 2

[u408661]

remote:   https://hg.mozilla.org/integration/mozilla-inbound/rev/f3d006fd5aa5

Comment 3

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/f3d006fd5aa5