Mercurial > hg
view tests/test-logexchange.t @ 40326:fed697fa1734
sqlitestore: file storage backend using SQLite
This commit provides an extension which uses SQLite to store file
data (as opposed to revlogs).
As the inline documentation describes, there are still several
aspects to the extension that are incomplete. But it's a start.
The extension does support basic clone, checkout, and commit
workflows, which makes it suitable for simple use cases.
One notable missing feature is support for "bundlerepos." This is
probably responsible for the most test failures when the extension
is activated as part of the test suite.
All revision data is stored in SQLite. Data is stored as zstd
compressed chunks (default if zstd is available), zlib compressed
chunks (default if zstd is not available), or raw chunks (if
configured or if a compressed delta is not smaller than the raw
delta). This makes things very similar to revlogs.
Unlike revlogs, the extension doesn't yet enforce a limit on delta
chain length. This is an obvious limitation and should be addressed.
This is somewhat mitigated by the use of zstd, which is much faster
than zlib to decompress.
There is a dedicated table for storing deltas. Deltas are stored
by the SHA-1 hash of their uncompressed content. The "fileindex" table
has columns that reference the delta for each revision and the base
delta that delta should be applied against. A recursive SQL query
is used to resolve the delta chain along with the delta data.
By storing deltas by hash, we are able to de-duplicate delta storage!
With revlogs, the same deltas in different revlogs would result in
duplicate storage of that delta. In this scheme, inserting the
duplicate delta is a no-op and delta chains simply reference the
existing delta.
When initially implementing this extension, I did not have
content-indexed deltas and deltas could be duplicated across files
(just like revlogs). When I implemented content-indexed deltas, the
size of the SQLite database for a full clone of mozilla-unified
dropped:
before: 2,554,261,504 bytes
after: 2,488,754,176 bytes
Surprisingly, this is still larger than the bytes size of revlog
files:
revlog files: 2,104,861,230 bytes
du -b: 2,254,381,614
I would have expected storage to be smaller since we're not limiting
delta chain length and since we're using zstd instead of zlib. I
suspect the SQLite indexes and per-column overhead account for the
bulk of the differences. (Keep in mind that revlog uses a 64-byte
packed struct for revision index data and deltas are stored without
padding. Aside from the 12 unused bytes in the 32 byte node field,
revlogs are pretty efficient.) Another source of overhead is file
name storage. With revlogs, file names are stored in the filesystem.
But with SQLite, we need to store file names in the database. This is
roughly equivalent to the size of the fncache file, which for the
mozilla-unified repository is ~34MB.
Since the SQLite database isn't append-only and since delta chains
can reference any delta, this opens some interesting possibilities.
For example, we could store deltas in reverse, such that fulltexts
are stored for newer revisions and deltas are applied to reconstruct
older revisions. This is likely a more optimal storage strategy for
version control, as new data tends to be more frequently accessed
than old data. We would obviously need wire protocol support for
transferring revision data from newest to oldest. And we would
probably need some kind of mechanism for "re-encoding" stores. But
it should be doable.
This extension is very much experimental quality. There are a handful
of features that don't work. It probably isn't suitable for day-to-day
use. But it could be used in limited cases (e.g. read-only checkouts
like in CI). And it is also a good proving ground for alternate
storage backends. As we continue to define interfaces for all things
storage, it will be useful to have a viable alternate storage backend
to see how things shake out in practice.
test-storage.py passes on Python 2 and introduces no new test failures on
Python 3. Having the storage-level unit tests has proved to be insanely
useful when developing this extension. Those tests caught numerous bugs
during development and I'm convinced this style of testing is the way
forward for ensuring alternate storage backends work as intended. Of
course, test coverage isn't close to what it needs to be. But it is
a start. And what coverage we have gives me confidence that basic store
functionality is implemented properly.
Differential Revision: https://phab.mercurial-scm.org/D4928
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Tue, 09 Oct 2018 08:50:13 -0700 |
parents | fd4d59cf2ebb |
children | d7304434390f |
line wrap: on
line source
Testing the functionality to pull remotenames ============================================= $ cat >> $HGRCPATH << EOF > [ui] > ssh = "$PYTHON" "$TESTDIR/dummyssh" > [alias] > glog = log -G -T '{rev}:{node|short} {desc}' > [extensions] > remotenames = > show = > EOF Making a server repo -------------------- $ hg init server $ cd server $ for ch in a b c d e f g h; do > echo "foo" >> $ch > hg ci -Aqm "Added "$ch > done $ hg glog @ 7:ec2426147f0e Added h | o 6:87d6d6676308 Added g | o 5:825660c69f0c Added f | o 4:aa98ab95a928 Added e | o 3:62615734edd5 Added d | o 2:28ad74487de9 Added c | o 1:29becc82797a Added b | o 0:18d04c59bb5d Added a $ hg bookmark -r 3 foo $ hg bookmark -r 6 bar $ hg up 4 0 files updated, 0 files merged, 3 files removed, 0 files unresolved $ hg branch wat marked working directory as branch wat (branches are permanent and global, did you want a bookmark?) $ echo foo >> bar $ hg ci -Aqm "added bar" Making a client repo -------------------- $ cd .. $ hg clone ssh://user@dummy/server client requesting all changes adding changesets adding manifests adding file changes added 9 changesets with 9 changes to 9 files (+1 heads) new changesets 18d04c59bb5d:3e1487808078 updating to branch default 8 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd client $ cat .hg/logexchange/bookmarks 0 87d6d66763085b629e6d7ed56778c79827273022\x00default\x00bar (esc) 62615734edd52f06b6fb9c2beb429e4fe30d57b8\x00default\x00foo (esc) $ cat .hg/logexchange/branches 0 ec2426147f0e39dbc9cef599b066be6035ce691d\x00default\x00default (esc) 3e1487808078543b0af6d10dadf5d46943578db0\x00default\x00wat (esc) $ hg show work o 3e14 (wat) (default/wat) added bar ~ @ ec24 (default/default) Added h ~ $ hg update "default/wat" 1 files updated, 0 files merged, 3 files removed, 0 files unresolved $ hg identify 3e1487808078 (wat) tip Making a new server ------------------- $ cd .. $ hg init server2 $ cd server2 $ hg pull ../server/ pulling from ../server/ requesting all changes adding changesets adding manifests adding file changes added 9 changesets with 9 changes to 9 files (+1 heads) adding remote bookmark bar adding remote bookmark foo new changesets 18d04c59bb5d:3e1487808078 (run 'hg heads' to see heads) Pulling form the new server --------------------------- $ cd ../client/ $ hg pull ../server2/ pulling from ../server2/ searching for changes no changes found $ cat .hg/logexchange/bookmarks 0 62615734edd52f06b6fb9c2beb429e4fe30d57b8\x00default\x00foo (esc) 87d6d66763085b629e6d7ed56778c79827273022\x00default\x00bar (esc) 87d6d66763085b629e6d7ed56778c79827273022\x00$TESTTMP/server2\x00bar (esc) 62615734edd52f06b6fb9c2beb429e4fe30d57b8\x00$TESTTMP/server2\x00foo (esc) $ cat .hg/logexchange/branches 0 3e1487808078543b0af6d10dadf5d46943578db0\x00default\x00wat (esc) ec2426147f0e39dbc9cef599b066be6035ce691d\x00default\x00default (esc) ec2426147f0e39dbc9cef599b066be6035ce691d\x00$TESTTMP/server2\x00default (esc) 3e1487808078543b0af6d10dadf5d46943578db0\x00$TESTTMP/server2\x00wat (esc) $ hg log -G @ changeset: 8:3e1487808078 | branch: wat | tag: tip | remote branch: $TESTTMP/server2/wat | remote branch: default/wat | parent: 4:aa98ab95a928 | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: added bar | | o changeset: 7:ec2426147f0e | | remote branch: $TESTTMP/server2/default | | remote branch: default/default | | user: test | | date: Thu Jan 01 00:00:00 1970 +0000 | | summary: Added h | | | o changeset: 6:87d6d6676308 | | bookmark: bar | | remote bookmark: $TESTTMP/server2/bar | | remote bookmark: default/bar | | hoisted name: bar | | user: test | | date: Thu Jan 01 00:00:00 1970 +0000 | | summary: Added g | | | o changeset: 5:825660c69f0c |/ user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: Added f | o changeset: 4:aa98ab95a928 | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: Added e | o changeset: 3:62615734edd5 | bookmark: foo | remote bookmark: $TESTTMP/server2/foo | remote bookmark: default/foo | hoisted name: foo | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: Added d | o changeset: 2:28ad74487de9 | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: Added c | o changeset: 1:29becc82797a | user: test | date: Thu Jan 01 00:00:00 1970 +0000 | summary: Added b | o changeset: 0:18d04c59bb5d user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: Added a Testing the templates provided by remotenames extension `remotenames` keyword $ hg log -G -T "{rev}:{node|short} {remotenames}\n" @ 8:3e1487808078 $TESTTMP/server2/wat default/wat | | o 7:ec2426147f0e $TESTTMP/server2/default default/default | | | o 6:87d6d6676308 $TESTTMP/server2/bar default/bar | | | o 5:825660c69f0c |/ o 4:aa98ab95a928 | o 3:62615734edd5 $TESTTMP/server2/foo default/foo | o 2:28ad74487de9 | o 1:29becc82797a | o 0:18d04c59bb5d `remotebookmarks` and `remotebranches` keywords $ hg log -G -T "{rev}:{node|short} [{remotebookmarks}] ({remotebranches})" @ 8:3e1487808078 [] ($TESTTMP/server2/wat default/wat) | | o 7:ec2426147f0e [] ($TESTTMP/server2/default default/default) | | | o 6:87d6d6676308 [$TESTTMP/server2/bar default/bar] () | | | o 5:825660c69f0c [] () |/ o 4:aa98ab95a928 [] () | o 3:62615734edd5 [$TESTTMP/server2/foo default/foo] () | o 2:28ad74487de9 [] () | o 1:29becc82797a [] () | o 0:18d04c59bb5d [] () The `hoistednames` template keyword $ hg log -GT "{rev}:{node|short} ({hoistednames})" @ 8:3e1487808078 () | | o 7:ec2426147f0e () | | | o 6:87d6d6676308 (bar) | | | o 5:825660c69f0c () |/ o 4:aa98ab95a928 () | o 3:62615734edd5 (foo) | o 2:28ad74487de9 () | o 1:29becc82797a () | o 0:18d04c59bb5d () Testing the revsets provided by remotenames extension `remotenames` revset $ hg log -r "remotenames()" -GT "{rev}:{node|short} {remotenames}\n" @ 8:3e1487808078 $TESTTMP/server2/wat default/wat : : o 7:ec2426147f0e $TESTTMP/server2/default default/default : | : o 6:87d6d6676308 $TESTTMP/server2/bar default/bar :/ o 3:62615734edd5 $TESTTMP/server2/foo default/foo | ~ `remotebranches` revset $ hg log -r "remotebranches()" -GT "{rev}:{node|short} {remotenames}\n" @ 8:3e1487808078 $TESTTMP/server2/wat default/wat | ~ o 7:ec2426147f0e $TESTTMP/server2/default default/default | ~ `remotebookmarks` revset $ hg log -r "remotebookmarks()" -GT "{rev}:{node|short} {remotenames}\n" o 6:87d6d6676308 $TESTTMP/server2/bar default/bar : o 3:62615734edd5 $TESTTMP/server2/foo default/foo | ~ Updating to revision using hoisted name --------------------------------------- Deleting local bookmark to make sure we update to hoisted name only $ hg bookmark -d bar $ hg up bar 2 files updated, 0 files merged, 1 files removed, 0 files unresolved $ hg log -r . changeset: 6:87d6d6676308 remote bookmark: $TESTTMP/server2/bar remote bookmark: default/bar hoisted name: bar user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: Added g When both local bookmark and hoisted name exists but on different revs $ hg up 8 1 files updated, 0 files merged, 2 files removed, 0 files unresolved $ hg bookmark foo moving bookmark 'foo' forward from 62615734edd5 Local bookmark should take precedence over hoisted name $ hg up foo 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg log -r . changeset: 8:3e1487808078 branch: wat bookmark: foo tag: tip remote branch: $TESTTMP/server2/wat remote branch: default/wat parent: 4:aa98ab95a928 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: added bar $ hg bookmarks $TESTTMP/server2/bar 6:87d6d6676308 $TESTTMP/server2/foo 3:62615734edd5 default/bar 6:87d6d6676308 default/foo 3:62615734edd5 * foo 8:3e1487808078 Testing the remotenames sychronization during `hg push` ------------------------------------------------------- $ cd ../server/ $ hg bookmark foo moving bookmark 'foo' forward from 62615734edd5 After the push, default/foo should move to rev 8 $ cd ../client/ $ hg push pushing to ssh://user@dummy/server searching for changes no changes found [1] $ hg log -Gr 'remotenames()' @ changeset: 8:3e1487808078 : branch: wat : bookmark: foo : tag: tip : remote bookmark: default/foo : hoisted name: foo : remote branch: $TESTTMP/server2/wat : remote branch: default/wat : parent: 4:aa98ab95a928 : user: test : date: Thu Jan 01 00:00:00 1970 +0000 : summary: added bar : : o changeset: 7:ec2426147f0e : | remote branch: $TESTTMP/server2/default : | remote branch: default/default : | user: test : | date: Thu Jan 01 00:00:00 1970 +0000 : | summary: Added h : | : o changeset: 6:87d6d6676308 :/ remote bookmark: $TESTTMP/server2/bar : remote bookmark: default/bar : hoisted name: bar : user: test : date: Thu Jan 01 00:00:00 1970 +0000 : summary: Added g : o changeset: 3:62615734edd5 | remote bookmark: $TESTTMP/server2/foo ~ user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: Added d $ hg bookmarks $TESTTMP/server2/bar 6:87d6d6676308 $TESTTMP/server2/foo 3:62615734edd5 default/bar 6:87d6d6676308 default/foo 8:3e1487808078 * foo 8:3e1487808078 Testing the names argument to remotenames, remotebranches and remotebookmarks revsets -------------------------------------------------------------------------------------- $ cd .. $ hg clone ssh://user@dummy/server client2 requesting all changes adding changesets adding manifests adding file changes added 9 changesets with 9 changes to 9 files (+1 heads) new changesets 18d04c59bb5d:3e1487808078 updating to branch default 8 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd server2 $ hg up wat 6 files updated, 0 files merged, 0 files removed, 0 files unresolved $ echo foo > watwat $ hg ci -Aqm "added watwat" $ hg bookmark bar abort: bookmark 'bar' already exists (use -f to force) [255] $ hg up ec24 3 files updated, 0 files merged, 2 files removed, 0 files unresolved $ echo i > i $ hg ci -Aqm "added i" $ cd ../client2 $ echo "[paths]" >> .hg/hgrc $ echo "server2 = $TESTTMP/server2" >> .hg/hgrc $ hg pull server2 pulling from $TESTTMP/server2 searching for changes adding changesets adding manifests adding file changes added 2 changesets with 2 changes to 2 files new changesets f34adec73c21:bf433e48adea (run 'hg update' to get a working copy) $ hg log -Gr 'remotenames()' -T '{rev}:{node|short} {desc}\n({remotebranches}) [{remotebookmarks}]\n\n' o 10:bf433e48adea added i | (server2/default) [] | | o 9:f34adec73c21 added watwat | | (server2/wat) [] | | | o 8:3e1487808078 added bar | : (default/wat) [default/foo] | : @ : 7:ec2426147f0e Added h | : (default/default) [] | : o : 6:87d6d6676308 Added g :/ () [default/bar server2/bar] : o 3:62615734edd5 Added d | () [server2/foo] ~ Testing for a single remote name which exists $ hg log -r 'remotebranches("default/wat")' -GT "{rev}:{node|short} {remotebranches}\n" o 8:3e1487808078 default/wat | ~ $ hg log -r 'remotebookmarks("server2/foo")' -GT "{rev}:{node|short} {remotebookmarks}\n" o 3:62615734edd5 server2/foo | ~ $ hg log -r 'remotenames("re:default")' -GT "{rev}:{node|short} {remotenames}\n" o 10:bf433e48adea server2/default | | o 8:3e1487808078 default/foo default/wat | | | ~ @ 7:ec2426147f0e default/default | o 6:87d6d6676308 default/bar server2/bar | ~ Testing for a literal name which does not exists, which should fail. $ hg log -r 'remotebranches(def)' -GT "{rev}:{node|short} {remotenames}\n" abort: remote name 'def' does not exist! [255] $ hg log -r 'remotebookmarks("server3")' -GT "{rev}:{node|short} {remotenames}\n" abort: remote name 'server3' does not exist! [255] $ hg log -r 'remotenames("server3")' -GT "{rev}:{node|short} {remotenames}\n" abort: remote name 'server3' does not exist! [255] Testing for a pattern which does not match anything, which shouldn't fail. $ hg log -r 'remotenames("re:^server3$")' Testing for multiple names, which is not supported. $ hg log -r 'remotenames("re:default", "re:server2")' -GT "{rev}:{node|short} {remotenames}\n" hg: parse error: only one argument accepted [255] $ hg log -r 'remotebranches("default/wat", "server2/wat")' -GT "{rev}:{node|short} {remotebranches}\n" hg: parse error: only one argument accepted [255] $ hg log -r 'remotebookmarks("default/foo", "server2/foo")' -GT "{rev}:{node|short} {remotebookmarks}\n" hg: parse error: only one argument accepted [255] Testing pattern matching $ hg log -r 'remotenames("re:def")' -GT "{rev}:{node|short} {remotenames}\n" o 10:bf433e48adea server2/default | | o 8:3e1487808078 default/foo default/wat | | | ~ @ 7:ec2426147f0e default/default | o 6:87d6d6676308 default/bar server2/bar | ~ $ hg log -r 'remotebranches("re:ser.*2")' -GT "{rev}:{node|short} {remotebranches}\n" o 10:bf433e48adea server2/default | ~ o 9:f34adec73c21 server2/wat | ~