1128475 - mozilla-beta and elephant size HTTP headers

Status: RESOLVED DUPLICATE of bug 927219

(Developer Services :: Mercurial: hg.mozilla.org, defect)

Description

[Michal Purzynski [:michal`] (use NEEDINFO)]

Hello.

When working on a separate bug, Bob Clary and I noticed a problem with our current hg.mozilla.org repo. The mozilla-beta cannot be cloned when using proxies such as squid, because mercurial sends HUGE HTTP headers - around 96KB of them.

That's quite unusual. Furthermore, it only happens on mozilla-beta, other branches are fine.

Do you think this is a normal and desirable behavior or a bug?

For more information, see the wireshark's dump of traffic

https://bugzilla.mozilla.org/show_bug.cgi?id=1127287#c20

(I'll CC you if you cannot see this bug).

Comment 1

[Gregory Szorc [:gps]]

This is expected. The size of the headers grows in linear proportion to the number of heads in the repository. That's one reason we were attempting to merge old heads in bug 927219. As a result of a mistake, mozilla-beta is currently carrying a few hundred more (redundant) heads than it should. These should hopefully be stripped soon. But, total head size won't decrease by more than half of where it is today until heads are actively merged. And given the vcs sync pain head merging caused, that likely won't be done any time soon.

See also bug 1030239.

A work around is to only pull a specific revision from the repo. e.g. `hg pull -r default`. There was also a bug in older versions of Mercurial that could cause clients to send many more headers than they should. Upgrading to Mercurial 3.3 (released today) should address that.