From: | Ron Johnson <ron(dot)l(dot)johnson(at)cox(dot)net> |
---|---|
To: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Storing images in PostgreSQL databases (again) |
Date: | 2006-10-06 01:45:50 |
Message-ID: | 4525B54E.8090604@cox.net |
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Thread: | |
Lists: | pgsql-general |
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On 10/05/06 19:41, Bill Moran wrote:
> "Leonel Nunez" <lnunez(at)enelserver(dot)com> wrote:
>>> If the database had built-in functions to manipulate images (make a
>>> thumbnail, add text ont it.., make a montage of two pictures) and I could
>>> write something like
>>> select thumbnail(image_field, 100, 100) from images_table
>>> that would be a good reason to go the db route versus the filesystem
>>> route.
>
> <snip>
>
>> With Python and the python imaging library you can do this :
>>
>> image is a bytea field
>>
>> curs = conn.cursor ()
>> curs.execute( "select image from images where name = %s" ,(thename, ))
>> row = curs.fetchone()
>> if row:
>> im = Image.open (StringIO.StringIO(row[0]))
>> im.thumbnail (160,120 )
>> imagetmp = StringIO.StringIO()
>> im.save ( imagetmp , "JPEG")
>> print ("Content-type: image/jpeg\n\n")
>> print ( imagetmp.getvalue())
>
> I think part of the point, which you missed, is the convenience of having
> the thumbnailing as part of the SQL language by making it a stored
> procedure.
Would untrusted pl/python be able to do this?
> I did a presentation for WPLUG not too long ago where I created C
> functions in Postgres compiled against the GSOAP library that allowed
> you to make simple SOAP calls in SQL within PostgreSQL. Neat stuff.
>
> The problem with creating those kinds of functions is the CPU overhead.
> We'll be generating the thumbnails and storing them in a "thumbnail"
> field in the record, so we don't have to regenerate the thumbnail each
> time it's needed.
>
> BTW: our reason for keeping the thumbnails in fields is so they can be
> replicated with Slony along with the rest of the database.
>
- --
Ron Johnson, Jr.
Jefferson LA USA
Is "common sense" really valid?
For example, it is "common sense" to white-power racists that
whites are superior to blacks, and that those with brown skins
are mud people.
However, that "common sense" is obviously wrong.
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