* Read manifests directly into the database, rather than first reading

  them into memory.  This brings memory use down to (more or less)
  O(1).  For instance, on my test case, the maximum resident size of
  download-using-manifests while filling the DB went from 142 MiB to
  11 MiB.

1 files changed, 65 insertions, 60 deletions

diff --git a/scripts/NixManifest.pm.in b/scripts/NixManifest.pm.in
index 20749acd7e40..2d4b626570fb 100644
--- a/scripts/NixManifest.pm.in
+++ b/scripts/NixManifest.pm.in
@@ -6,6 +6,23 @@ use File::Path;
 use Fcntl ':flock';
 
 
+sub addNAR {
+    my ($narFiles, $storePath, $info) = @_;
+    
+    $$narFiles{$storePath} = []
+        unless defined $$narFiles{$storePath};
+
+    my $narFileList = $$narFiles{$storePath};
+
+    my $found = 0;
+    foreach my $narFile (@{$narFileList}) {
+        $found = 1 if $narFile->{url} eq $info->{url};
+    }
+    
+    push @{$narFileList}, $info if !$found;
+}
+
+
 sub addPatch {
     my ($patches, $storePath, $patch) = @_;
 
@@ -27,8 +44,8 @@ sub addPatch {
 }
 
 
-sub readManifest {
-    my ($manifest, $narFiles, $patches) = @_;
+sub readManifest_ {
+    my ($manifest, $addNAR, $addPatch) = @_;
 
     open MANIFEST, "<$manifest"
         or die "cannot open `$manifest': $!";
@@ -72,35 +89,22 @@ sub readManifest {
                 $inside = 0;
 
                 if ($type eq "narfile") {
-
-                    $$narFiles{$storePath} = []
-                        unless defined $$narFiles{$storePath};
-
-                    my $narFileList = $$narFiles{$storePath};
-
-                    my $found = 0;
-                    foreach my $narFile (@{$narFileList}) {
-                        $found = 1 if $narFile->{url} eq $url;
-                    }
-                    if (!$found) {
-                        push @{$narFileList},
-                            { url => $url, hash => $hash, size => $size
-                            , narHash => $narHash, narSize => $narSize
-                            , references => $references
-                            , deriver => $deriver
-                            , system => $system
-                            };
-                    }
-                
+                    &$addNAR($storePath,
+                        { url => $url, hash => $hash, size => $size
+                        , narHash => $narHash, narSize => $narSize
+                        , references => $references
+                        , deriver => $deriver
+                        , system => $system
+                        });
                 }
 
                 elsif ($type eq "patch") {
-                    addPatch $patches, $storePath,
+                    &$addPatch($storePath,
                         { url => $url, hash => $hash, size => $size
                         , basePath => $basePath, baseHash => $baseHash
                         , narHash => $narHash, narSize => $narSize
                         , patchType => $patchType
-                        };
+                        });
                 }
 
             }
@@ -134,6 +138,14 @@ sub readManifest {
 }
 
 
+sub readManifest {
+    my ($manifest, $narFiles, $patches) = @_;
+    readManifest_($manifest,
+        sub { addNAR($narFiles, @_); },
+        sub { addPatch($patches, @_); } );
+}
+
+
 sub writeManifest {
     my ($manifest, $narFiles, $patches, $noCompress) = @_;
 
@@ -205,7 +217,7 @@ sub updateManifestDB {
     my $dbPath = "$manifestDir/cache.sqlite";
 
     # Open/create the database.
-    my $dbh = DBI->connect("dbi:SQLite:dbname=$dbPath", "", "")
+    our $dbh = DBI->connect("dbi:SQLite:dbname=$dbPath", "", "")
         or die "cannot open database `$dbPath'";
     $dbh->{AutoCommit} = 0;
     $dbh->{RaiseError} = 1;
@@ -279,47 +291,40 @@ EOF
             "select 1 from Manifests where path = ? and timestamp = ?",
             {}, $manifest, $timestamp)} == 1;
 
-        # !!! Insert directly into the DB.
-        my %narFiles;
-        my %patches;
-        my $version = readManifest($manifest, \%narFiles, \%patches);
-        
-        if ($version < 3) {
-            die "you have an old-style manifest `$manifest'; please delete it";
-        }
-        if ($version >= 10) {
-            die "manifest `$manifest' is too new; please delete it or upgrade Nix";
-        }
-
         $dbh->do("delete from Manifests where path = ?", {}, $manifest);
                  
         $dbh->do("insert into Manifests(path, timestamp) values (?, ?)",
                  {}, $manifest, $timestamp);
 
-        my $id = $dbh->sqlite_last_insert_rowid();
-
-        foreach my $storePath (keys %narFiles) {
-            my $narFileList = $narFiles{$storePath};
-            foreach my $narFile (@{$narFiles{$storePath}}) {
-                $dbh->do(
-                    "insert into NARs(manifest, storePath, url, hash, size, narHash, " .
-                    "narSize, refs, deriver, system) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
-                    {}, $id, $storePath, $narFile->{url}, $narFile->{hash}, $narFile->{size},
-                    $narFile->{narHash}, $narFile->{narSize}, $narFile->{references},
-                    $narFile->{deriver}, $narFile->{system});
-            }
+        our $id = $dbh->sqlite_last_insert_rowid();
+
+        sub addNARToDB {
+            my ($storePath, $narFile) = @_;
+            $dbh->do(
+                "insert into NARs(manifest, storePath, url, hash, size, narHash, " .
+                "narSize, refs, deriver, system) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+                {}, $id, $storePath, $narFile->{url}, $narFile->{hash}, $narFile->{size},
+                $narFile->{narHash}, $narFile->{narSize}, $narFile->{references},
+                $narFile->{deriver}, $narFile->{system});
+        };
+        
+        sub addPatchToDB {
+            my ($storePath, $patch) = @_;
+            $dbh->do(
+                "insert into Patches(manifest, storePath, basePath, baseHash, url, hash, " .
+                "size, narHash, narSize, patchType) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+                {}, $id, $storePath, $patch->{basePath}, $patch->{baseHash}, $patch->{url},
+                $patch->{hash}, $patch->{size}, $patch->{narHash}, $patch->{narSize},
+                $patch->{patchType});
+        };
+
+        my $version = readManifest_($manifest, \&addNARToDB, \&addPatchToDB);
+        
+        if ($version < 3) {
+            die "you have an old-style manifest `$manifest'; please delete it";
         }
-
-        foreach my $storePath (keys %patches) {
-            my $patchList = $patches{$storePath};
-            foreach my $patch (@{$patchList}) {
-                $dbh->do(
-                    "insert into Patches(manifest, storePath, basePath, baseHash, url, hash, " .
-                    "size, narHash, narSize, patchType) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
-                    {}, $id, $storePath, $patch->{basePath}, $patch->{baseHash}, $patch->{url},
-                    $patch->{hash}, $patch->{size}, $patch->{narHash}, $patch->{narSize},
-                    $patch->{patchType});
-            }
+        if ($version >= 10) {
+            die "manifest `$manifest' is too new; please delete it or upgrade Nix";
         }
     }