CODEWITHSUNDEEP
delphiblobstreamingfirebird
Homer Jones
Homer Jones

Reputation: 53

Out of memory while adding documents to a Firebird BLOB field with Delphi

The following code will add 3000 to 4000 documents of various sizes to a Firebird Blob field before running out of memory. I believe I have freed the streams I create, but I may not be doing it correctly. Streams are a new tool in my toolbox. Can anyone spot what I'm doing wrong?

procedure TfrmMigration.Button1Click(Sender: TObject);
var
  DocFile: string;
  Blob: TStream;
  fs: TFileStream;
begin
  with DM.qImageList do
  begin
    close;
    SQL.Text := ImgListSQL;
    open;
    First;

    while not eof do
    begin
      { Ignore if previously done.}
      if (FieldByName('Document_Files').IsNull) then
      begin
        DocFile := Trim(gsDocumentPath + '\' + FieldByName('ImageName').asString);
        if FileExists(DocFile) then
        begin
          edit;
          Blob := CreateBlobStream(FieldByName('Document_Files'), bmWrite);
          try
            Blob.Seek(0, soFromBeginning);
            fs := TFileStream.Create(DocFile, fmOpenRead or fmShareDenyWrite);
            try
              Blob.CopyFrom(fs, fs.Size);
            finally
              fs.free;
            end;
          finally
            Blob.free;
          end;
          post;
        end;
      end;
      next;
    end;
  end;
end;

Upvotes: 1

Views: 145

Answers (1)

Homer Jones
Homer Jones

Reputation: 53

Thank you all for pitching in. You were correct. There was nothing actually wrong with my code.

I solved the memory depletion issue by turning off CacheBlobs in my query component. I'm using IBDAC, and all I needed to do was set that property to False. That allowed me to copy 107,389 documents into the database in a little over one hour on a fairly slow Windows 11 machine (running the app in the IDE). It seems I had been putting data into cache faster than it was being removed.

Again, thank you for all your comments.

Upvotes: 1

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