Bug#922240: ftp.debian.org: consider switching to merged pdiffs
Package: ftp.debian.org
Severity: wishlist
I'd like to reopen the discussion about the pdiff format on
the archive. Currently a pdiff is generated for each generation
of the archive, which means that apt has to fetch 4 pdiffs per
day it has to catch up.
This means that for a 10 day interval, we have to fetch 40 pdiffs
per index. Assuming amd64+i386 with Contents files and Sources
enabled, we are looking at 2*(1+1+1)*40=6*40=240 files to fetch.
This is clearly suboptimal, as it makes the log output unreadable,
and causes severe slowdowns on high-latency or non-persistent
connections.
It might make sense to consider switching to merged pdiffs, which generate
one Pdiff from each generation to the latest one. This can be done either
by preserving old index files and creating pdiffs from them, or simply by
concatenating the new pdiff to the old ones.
A point against it could be increased space requirements and time to
compress the pdiffs, but I'd welcome more discussion on that subject.
--
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