Mercurial > hg
view tests/test-relink.t @ 27430:e240e914d226 stable
revlog: seek to end of file before writing (issue4943)
Revlogs were recently refactored to open file handles in "a+" and use a
persistent file handle for reading and writing. This drastically
reduced the number of file handles being opened.
Unfortunately, it appears that some versions of Solaris lose the file
offset when performing a write after the handle has been seeked.
The simplest workaround is to seek to EOF on files opened in a+ mode
before writing to them, which is what this patch does.
Ideally, this code would exist in the vfs layer. However, this would
require creating a proxy class for file objects in order to provide a
custom implementation of write(). This would add overhead. Since
revlogs are the only files we open in a+ mode, the one-off workaround
in revlog.py should be sufficient.
This patch appears to have little to no impact on performance on my
Linux machine.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Thu, 17 Dec 2015 17:16:02 -0800 |
parents | bd625cd4e5e7 |
children | 75be14993fda |
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#require hardlink $ echo "[extensions]" >> $HGRCPATH $ echo "relink=" >> $HGRCPATH $ fix_path() { > tr '\\' / > } $ cat > arelinked.py <<EOF > import sys, os > from mercurial import util > path1, path2 = sys.argv[1:3] > if util.samefile(path1, path2): > print '%s == %s' % (path1, path2) > else: > print '%s != %s' % (path1, path2) > EOF create source repository $ hg init repo $ cd repo $ echo a > a $ echo b > b $ hg ci -Am addfile adding a adding b $ cat "$TESTDIR/binfile.bin" >> a $ cat "$TESTDIR/binfile.bin" >> b $ hg ci -Am changefiles make another commit to create files larger than 1 KB to test formatting of final byte count $ cat "$TESTDIR/binfile.bin" >> a $ cat "$TESTDIR/binfile.bin" >> b $ hg ci -m anotherchange don't sit forever trying to double-lock the source repo $ hg relink . relinking $TESTTMP/repo/.hg/store to $TESTTMP/repo/.hg/store (glob) there is nothing to relink Test files are read in binary mode $ $PYTHON -c "file('.hg/store/data/dummy.i', 'wb').write('a\r\nb\n')" $ cd .. clone and pull to break links $ hg clone --pull -r0 repo clone adding changesets adding manifests adding file changes added 1 changesets with 2 changes to 2 files updating to branch default 2 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd clone $ hg pull -q $ echo b >> b $ hg ci -m changeb created new head $ $PYTHON -c "file('.hg/store/data/dummy.i', 'wb').write('a\nb\r\n')" relink $ hg relink --debug --config progress.debug=true | fix_path relinking $TESTTMP/repo/.hg/store to $TESTTMP/clone/.hg/store tip has 2 files, estimated total number of files: 3 collecting: 00changelog.i 1/3 files (33.33%) collecting: 00manifest.i 2/3 files (66.67%) collecting: a.i 3/3 files (100.00%) collecting: b.i 4/3 files (133.33%) collecting: dummy.i 5/3 files (166.67%) collected 5 candidate storage files not linkable: 00changelog.i not linkable: 00manifest.i pruning: data/a.i 3/5 files (60.00%) not linkable: data/b.i pruning: data/dummy.i 5/5 files (100.00%) pruned down to 2 probably relinkable files relinking: data/a.i 1/2 files (50.00%) not linkable: data/dummy.i relinked 1 files (1.36 KB reclaimed) $ cd .. check hardlinks $ python arelinked.py repo/.hg/store/data/a.i clone/.hg/store/data/a.i repo/.hg/store/data/a.i == clone/.hg/store/data/a.i $ python arelinked.py repo/.hg/store/data/b.i clone/.hg/store/data/b.i repo/.hg/store/data/b.i != clone/.hg/store/data/b.i