From cc770cdf9eb5e8174cab85ec3be143ed4158206f Mon Sep 17 00:00:00 2001
From: hjp <hjp@d47eeb7a-11fe-0310-b519-e5a4e12f9765>
Date: Sat, 29 Sep 2012 10:44:10 +0000
Subject: [PATCH] Read all checksums from the last session and store them in a
 hash. This should speed up retrieving checksums considerably.

---
 lib/Simba/CA.pm | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/lib/Simba/CA.pm b/lib/Simba/CA.pm
index 6db94cc..2207277 100644
--- a/lib/Simba/CA.pm
+++ b/lib/Simba/CA.pm
@@ -443,14 +443,7 @@ sub db_record_version {
     $self->{times}{db_record_version_insert_files} += $t2 - $t1;
     if ($f->{t} eq 'f' && !defined($f->{checksum})) {
         # this must be a link to the previous version
-        my $db_pv = $self->{dbh}->selectall_arrayref(
-                                    "select * from versions2 v, instances i
-                                     where file=? and session=? and v.id = i.version",
-                                    { Slice => {} },
-                                    $db_f->[0]{id},
-                                    $self->{last_backup_id}
-                                  );
-        $f->{checksum} = $db_pv->[0]{checksum};
+        $f->{checksum} = $self->get_checksum($db_f->[0]{id});
     }
     my $t2a = gettimeofday();
     $self->{times}{db_record_version_versions2_get_checksum} += $t2a - $t2;
@@ -525,6 +518,23 @@ sub db_record_version {
     $self->{times}{db_record_version} += $t4 - $t0;
 }
 
+sub get_checksum {
+    my ($self, $file) = @_;
+    if ($self->{caches}{file_checksums}{$self->{last_backup_id}}) {
+        return $self->{caches}{file_checksums}{$self->{last_backup_id}}{$file};
+    } else {
+        $self->{caches}{file_checksums}{$self->{last_backup_id}} = my $file_checksums = {};
+        my $sth = $self->{dbh}->prepare(
+                                    "select file, checksum from versions2 v, instances i
+                                     where session=? and v.id = i.version");
+        $sth->execute($self->{last_backup_id});
+        while (my ($file, $checksum) = $sth->fetchrow_array) {
+            $file_checksums->{$file} = $checksum;
+        }
+
+        return $file_checksums->{$file};
+    }
+}
 
 sub flush_insert_instances {
     my ($self) = @_;