From: "sean.swolfe@..." <sean.swolfe@...>
Date: 2006-02-02T06:48:12+09:00
Subject: "[BUG] Segmentation fault" on import script.

Hi gang. Sorry I haven't been able to respond to my last post about
Stop Word dictionaries. Been all too busy, but the posted info was very
useful.

Anyways, I have a bit of a situation. I have a collection of files,
around 10,000, that I need to parse and then suck that data into a
database, along with their linked images. I've had a script that has
been working pretty much for over 99.5% of the articles. Both the
article data, and the images were getting imported fine.

The images also have to go through a few processing steps before being
put into the database. They are resized to meet a certain constraint,
of a new document format, and are also resized again a few more times
to create 2 sizes of Thumbnails. I've been using the RMagick library to
do the image resizing.

I then had to make a change, because I realized that I wasn't
accommodating Animated GIF's and the resulting images that were saved
only contained the first frame. So now I added just a routine around
the resizing to iterate through an ImageList and do all the resizing
for each frame.

Now with this change I get a "[BUG] Segmentation fault" error. I
thought maybe I was starving the memory resources and the GC couldn't
keep up. (I'm uncomfortably unfamiliar with how the Ruby GC works as
opposed to Java or .NET GC), so I explicitly call garbage_collect after
about 100 imports. Still get the same error.

This happens in both Ruby 1.8.2 and 1.8.4 on Mac OSX as well as Linux.
Also, if it possibly means anything, this script is run in a Rails
environment using the runner script. It will run successfully for about
4000 articles before it bombs out.

Here is an excerpt of the possibly offensive code:
# image_object is an ActiveRecord object created
# a little before this code.
# get the ImageList from the image file.
image_file_list = Magick::ImageList.new(@old_site_path + image_path)
# create ImageLists for the thumbnails copied from the original
ImageList
smaller_list = image_file_list.copy
smallest_list = image_file_list.copy
tiniest_list = image_file_list.copy

# loop thorugh the images in the list
for image_index in 0...image_file_list.length
  image_file = image_file_list[image_index]
  # resize the loaded image to the main constraints
  image_file.change_geometry!('150x150') do |cols, rows, img|
    img.resize!(cols, rows)
    image_object.original_x = cols
    image_object.original_y = rows
   end

  smaller_list[image_index] = image_file.change_geometry('110x110') do
|cols, rows, img|
    image_object.thumb_x = cols
    image_object.thumb_y = rows
    img.resize(cols, rows)
  end
  smallest_list[image_index] = image_file.change_geometry('91x91') do
|cols, rows, img|
     image_object.small_thumb_x = cols
     image_object.small_thumb_y = rows
     img.resize(cols, rows)
  end
  tiniest_list[image_index] = image_file.change_geometry('50x50') do
|cols, rows, img|
    image_object.tiny_thumb_x = cols
    image_object.tiny_thumb_y = rows
    img.resize(cols, rows)
  end
end

image_object.original_filename = File.basename(image_path)
image_object.title = "#{ review_data[:artist] }: #{ review_data[:title]
}"

image_object.image_data = image_file_list.to_blob
image_object.tiny_thumb = tiniest_list.to_blob    # <-- segement fault
usually happens here.
image_object.big_thumb = smaller_list.to_blob
image_object.small_thumb = smallest_list.to_blob


Thanks in advance....