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git-remote-mediawiki: more efficient 'pull' in the best case

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The only way to fetch new revisions from a wiki before this patch was to
query each page for new revisions. This is good when tracking a small set
of pages on a large wiki, but very inefficient when tracking many pages
on a wiki with little activity.

Implement a new strategy that queries the wiki for its last global
revision, queries each new revision, and filter out pages that are not
tracked.

Signed-off-by: Simon Perrat <simon.perrat@ensimag.imag.fr>
Signed-off-by: Simon CATHEBRAS <Simon.Cathebras@ensimag.imag.fr>
Signed-off-by: Julien KHAYAT <Julien.Khayat@ensimag.imag.fr>
Signed-off-by: Charles ROUSSEL <Charles.Roussel@ensimag.imag.fr>
Signed-off-by: Guillaume SASDY <Guillaume.Sasdy@ensimag.imag.fr>
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Matthieu Moy 2012-07-06 12:03:14 +02:00 committed by Junio C Hamano
parent 312fa9aa12
commit 5a29217dda
2 changed files with 110 additions and 21 deletions
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114
contrib/mw-to-git/git-remote-mediawiki
View file

@ -13,12 +13,9 @@
#
# Known limitations:
#
# - Poor performance in the best case: it takes forever to check
# whether we're up-to-date (on fetch or push) or to fetch a few
# revisions from a large wiki, because we use exclusively a
# page-based synchronization. We could switch to a wiki-wide
# synchronization when the synchronization involves few revisions
# but the wiki is large.
# - Several strategies are provided to fetch modifications from the
# wiki, but no automatic heuristics is provided, the user has
# to understand and chose which strategy is appropriate for him.
#
# - Git renames could be turned into MediaWiki renames (see TODO
# below)
@ -89,6 +86,21 @@ my $shallow_import = run_git("config --get --bool remote.". $remotename .".shall
chomp($shallow_import);
$shallow_import = ($shallow_import eq "true");
# Fetch (clone and pull) by revisions instead of by pages. This behavior
# is more efficient when we have a wiki with lots of pages and we fetch
# the revisions quite often so that they concern only few pages.
# Possible values:
# - by_rev: perform one query per new revision on the remote wiki
# - by_page: query each tracked page for new revision
my $fetch_strategy = run_git("config --get remote.$remotename.fetchStrategy");
unless ($fetch_strategy) {
$fetch_strategy = run_git("config --get mediawiki.fetchStrategy");
}
chomp($fetch_strategy);
unless ($fetch_strategy) {
$fetch_strategy = "by_page";
}
# Dumb push: don't update notes and mediawiki ref to reflect the last push.
#
# Configurable with mediawiki.dumbPush, or per-remote with
@ -533,6 +545,26 @@ sub get_last_local_revision {
# Remember the timestamp corresponding to a revision id.
my %basetimestamps;
# Get the last remote revision without taking in account which pages are
# tracked or not. This function makes a single request to the wiki thus
# avoid a loop onto all tracked pages. This is useful for the fetch-by-rev
# option.
sub get_last_global_remote_rev {
mw_connect_maybe();
my $query = {
action => 'query',
list => 'recentchanges',
prop => 'revisions',
rclimit => '1',
rcdir => 'older',
};
my $result = $mediawiki->api($query);
return $result->{query}->{recentchanges}[0]->{revid};
}
# Get the last remote revision concerning the tracked pages and the tracked
# categories.
sub get_last_remote_revision {
mw_connect_maybe();
@ -803,9 +835,6 @@ sub mw_import_ref {
mw_connect_maybe();
my %pages_hash = get_mw_pages();
my @pages = values(%pages_hash);
print STDERR "Searching revisions...\n";
my $last_local = get_last_local_revision();
my $fetch_from = $last_local + 1;
@ -814,10 +843,35 @@ sub mw_import_ref {
} else {
print STDERR ", fetching from here.\n";
}
my ($n, @revisions) = fetch_mw_revisions(\@pages, $fetch_from);
# Creation of the fast-import stream
print STDERR "Fetching & writing export data...\n";
my $n = 0;
if ($fetch_strategy eq "by_rev") {
print STDERR "Fetching & writing export data by revs...\n";
$n = mw_import_ref_by_revs($fetch_from);
} elsif ($fetch_strategy eq "by_page") {
print STDERR "Fetching & writing export data by pages...\n";
$n = mw_import_ref_by_pages($fetch_from);
} else {
print STDERR "fatal: invalid fetch strategy \"$fetch_strategy\".\n";
print STDERR "Check your configuration variables remote.$remotename.fetchStrategy and mediawiki.fetchStrategy\n";
exit 1;
}
if ($fetch_from == 1 && $n == 0) {
print STDERR "You appear to have cloned an empty MediaWiki.\n";
# Something has to be done remote-helper side. If nothing is done, an error is
# thrown saying that HEAD is refering to unknown object 0000000000000000000
# and the clone fails.
}
}
sub mw_import_ref_by_pages {
my $fetch_from = shift;
my %pages_hash = get_mw_pages();
my @pages = values(%pages_hash);
my ($n, @revisions) = fetch_mw_revisions(\@pages, $fetch_from);
@revisions = sort {$a->{revid} <=> $b->{revid}} @revisions;
my @revision_ids = map $_->{revid}, @revisions;
@ -825,12 +879,26 @@ sub mw_import_ref {
return mw_import_revids($fetch_from, \@revision_ids, \%pages_hash);
}
sub mw_import_ref_by_revs {
my $fetch_from = shift;
my %pages_hash = get_mw_pages();
my $last_remote = get_last_global_remote_rev();
my @revision_ids = $fetch_from..$last_remote;
return mw_import_revids($fetch_from, \@revision_ids, \%pages_hash);
}
# Import revisions given in second argument (array of integers).
# Only pages appearing in the third argument (hash indexed by page titles)
# will be imported.
sub mw_import_revids {
my $fetch_from = shift;
my $revision_ids = shift;
my $pages = shift;
my $n = 0;
my $n_actual = 0;
my $last_timestamp = 0; # Placeholer in case $rev->timestamp is undefined
foreach my $pagerevid (@$revision_ids) {
@ -848,9 +916,20 @@ sub mw_import_revids {
my $result_page = $result_pages[0];
my $rev = $result_pages[0]->{revisions}->[0];
# Count page even if we skip it, since we display
# $n/$total and $total includes skipped pages.
$n++;
my $page_title = $result_page->{title};
if (!exists($pages->{$page_title})) {
print STDERR "$n/", scalar(@$revision_ids),
": Skipping revision #$rev->{revid} of $page_title\n";
next;
}
$n_actual++;
my %commit;
$commit{author} = $rev->{user} || 'Anonymous';
$commit{comment} = $rev->{comment} || '*Empty MediaWiki Message*';
@ -875,17 +954,10 @@ sub mw_import_revids {
# of a file do one common commit for both file and media page.
# Else do commit only for that page.
print STDERR "$n/", scalar(@$revision_ids), ": Revision #$rev->{revid} of $commit{title}\n";
import_file_revision(\%commit, ($fetch_from == 1), $n, \%mediafile);
import_file_revision(\%commit, ($fetch_from == 1), $n_actual, \%mediafile);
}
if ($fetch_from == 1 && $n == 0) {
print STDERR "You appear to have cloned an empty MediaWiki.\n";
# Something has to be done remote-helper side. If nothing is done, an error is
# thrown saying that HEAD is refering to unknown object 0000000000000000000
# and the clone fails.
}
return $n;
return $n_actual;
}
sub error_non_fast_forward {

17
contrib/mw-to-git/t/t9364-pull-by-rev.sh Executable file
View file

@ -0,0 +1,17 @@
#!/bin/sh
test_description='Test the Git Mediawiki remote helper: git pull by revision'
. ./test-gitmw-lib.sh
. ./push-pull-tests.sh
. $TEST_DIRECTORY/test-lib.sh
test_check_precond
test_expect_success 'configuration' '
git config --global mediawiki.fetchStrategy by_rev
'
test_push_pull
test_done