Mercurial > hg
view tests/test-basic.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> |
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date | Thu, 17 Dec 2015 17:16:02 -0800 |
parents | 8f88f768e24c |
children | 3aa50c9d89a0 |
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Create a repository: $ hg config defaults.backout=-d "0 0" defaults.commit=-d "0 0" defaults.shelve=--date "0 0" defaults.tag=-d "0 0" devel.all-warnings=true largefiles.usercache=$TESTTMP/.cache/largefiles (glob) ui.slash=True ui.interactive=False ui.mergemarkers=detailed ui.promptecho=True $ hg init t $ cd t Make a changeset: $ echo a > a $ hg add a $ hg commit -m test This command is ancient: $ hg history changeset: 0:acb14030fe0a tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: test Verify that updating to revision 0 via commands.update() works properly $ cat <<EOF > update_to_rev0.py > from mercurial import ui, hg, commands > myui = ui.ui() > repo = hg.repository(myui, path='.') > commands.update(myui, repo, rev=0) > EOF $ hg up null 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ python ./update_to_rev0.py 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg identify -n 0 Poke around at hashes: $ hg manifest --debug b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 644 a $ hg cat a a Verify should succeed: $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 1 files, 1 changesets, 1 total revisions At the end... $ cd ..