Mercurial > hg
view tests/test-largefiles-small-disk.t @ 28000:d4247c306d82
copies: optimize forward copy detection logic for rebases
Forward copy detection (i.e. detecting what files have been moved/copied in
commit X since ancestor Y) previously required diff'ing the manifests of both X
and Y. This was expensive since it required reading both entire manifests and
doing a set difference (they weren't already in a set because of the
lazymanifest work). This cost almost 1 second on very large repositories, and
happens N times for a rebase of N commits.
This patch optimizes it for the case of rebase. In a rebase, we are comparing a
commit against it's immediate parent, and therefore we can know what files
changed by looking at ctx.files(). This lets us drastically decrease the size
of the set comparison, and makes it O(# of changes) instead of O(size of
manifest). This makes it take 1ms instead of 1000ms.
author | Durham Goode <durham@fb.com> |
---|---|
date | Fri, 05 Feb 2016 13:23:24 -0800 |
parents | 8a021cd38719 |
children | 7356e6b1f5b8 |
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Test how largefiles abort in case the disk runs full $ cat > criple.py <<EOF > import os, errno, shutil > from mercurial import util > # > # this makes the original largefiles code abort: > def copyfileobj(fsrc, fdst, length=16*1024): > fdst.write(fsrc.read(4)) > raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC)) > shutil.copyfileobj = copyfileobj > # > # this makes the rewritten code abort: > def filechunkiter(f, size=65536, limit=None): > yield f.read(4) > raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC)) > util.filechunkiter = filechunkiter > # > def oslink(src, dest): > raise OSError("no hardlinks, try copying instead") > util.oslink = oslink > EOF $ echo "[extensions]" >> $HGRCPATH $ echo "largefiles =" >> $HGRCPATH $ hg init alice $ cd alice $ echo "this is a very big file" > big $ hg add --large big $ hg commit --config extensions.criple=$TESTTMP/criple.py -m big abort: No space left on device [255] The largefile is not created in .hg/largefiles: $ ls .hg/largefiles dirstate The user cache is not even created: >>> import os; os.path.exists("$HOME/.cache/largefiles/") False Make the commit with space on the device: $ hg commit -m big Now make a clone with a full disk, and make sure lfutil.link function makes copies instead of hardlinks: $ cd .. $ hg --config extensions.criple=$TESTTMP/criple.py clone --pull alice bob requesting all changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files updating to branch default getting changed largefiles abort: No space left on device [255] The largefile is not created in .hg/largefiles: $ ls bob/.hg/largefiles dirstate