git-svn: memoize _rev_list and rebuild

According to profile data, _rev_list and rebuild consume a large
portion of time.  Memoize the results of _rev_list and memoize
rebuild internals to avoid subprocess invocation.

When importing 15152 revisions on a LAN, time improved from 10
hours to 3-4 hours.

Signed-off-by: lin zuojian <manjian2006@gmail.com>
Signed-off-by: Eric Wong <normalperson@yhbt.net>

diff --git a/perl/Git/SVN.pm b/perl/Git/SVN.pm
index 5273ee886764423df0bacfa9b2fbc9b27c4852c4..6e804a271ca4c6b38b9769f16ace4fb9bc0b88cd 100644 (file)
--- a/perl/Git/SVN.pm
+++ b/perl/Git/SVN.pm
@@ -1599,6 +1599,7 @@ sub tie_for_persistent_memoization {
                my %lookup_svn_merge_cache;
                my %check_cherry_pick_cache;
                my %has_no_changes_cache;
+               my %_rev_list_cache;
 
                tie_for_persistent_memoization(\%lookup_svn_merge_cache,
                    "$cache_path/lookup_svn_merge");
@@ -1620,6 +1621,14 @@ sub tie_for_persistent_memoization {
                        SCALAR_CACHE => ['HASH' => \%has_no_changes_cache],
                        LIST_CACHE => 'FAULT',
                ;
+
+               tie_for_persistent_memoization(\%_rev_list_cache,
+                   "$cache_path/_rev_list");
+               memoize '_rev_list',
+                       SCALAR_CACHE => 'FAULT',
+                       LIST_CACHE => ['HASH' => \%_rev_list_cache],
+               ;
+
        }
 
        sub unmemoize_svn_mergeinfo_functions {
@@ -1629,6 +1638,7 @@ sub tie_for_persistent_memoization {
                Memoize::unmemoize 'lookup_svn_merge';
                Memoize::unmemoize 'check_cherry_pick';
                Memoize::unmemoize 'has_no_changes';
+               Memoize::unmemoize '_rev_list';
        }
 
        sub clear_memoized_mergeinfo_caches {
@@ -1959,11 +1969,25 @@ sub rebuild_from_rev_db {
        unlink $path or croak "unlink: $!";
 }
 
+#define a global associate map to record rebuild status
+my %rebuild_status;
+#define a global associate map to record rebuild verify status
+my %rebuild_verify_status;
+
 sub rebuild {
        my ($self) = @_;
        my $map_path = $self->map_path;
        my $partial = (-e $map_path && ! -z $map_path);
-       return unless ::verify_ref($self->refname.'^0');
+       my $verify_key = $self->refname.'^0';
+       if (!$rebuild_verify_status{$verify_key}) {
+               my $verify_result = ::verify_ref($verify_key);
+               if ($verify_result) {
+                       $rebuild_verify_status{$verify_key} = 1;
+               }
+       }
+       if (!$rebuild_verify_status{$verify_key}) {
+               return;
+       }
        if (!$partial && ($self->use_svm_props || $self->no_metadata)) {
                my $rev_db = $self->rev_db_path;
                $self->rebuild_from_rev_db($rev_db);
@@ -1977,10 +2001,21 @@ sub rebuild {
        print "Rebuilding $map_path ...\n" if (!$partial);
        my ($base_rev, $head) = ($partial ? $self->rev_map_max_norebuild(1) :
                (undef, undef));
+       my $key_value = ($head ? "$head.." : "") . $self->refname;
+       if (exists $rebuild_status{$key_value}) {
+               print "Done rebuilding $map_path\n" if (!$partial || !$head);
+               my $rev_db_path = $self->rev_db_path;
+               if (-f $self->rev_db_path) {
+                       unlink $self->rev_db_path or croak "unlink: $!";
+               }
+               $self->unlink_rev_db_symlink;
+               return;
+       }
        my ($log, $ctx) =
-           command_output_pipe(qw/rev-list --pretty=raw --reverse/,
-                               ($head ? "$head.." : "") . $self->refname,
+               command_output_pipe(qw/rev-list --pretty=raw --reverse/,
+                               $key_value,
                                '--');
+       $rebuild_status{$key_value} = 1;
        my $metadata_url = $self->metadata_url;
        remove_username($metadata_url);
        my $svn_uuid = $self->rewrite_uuid || $self->ra_uuid;