Re: Interesting problem with instances
Re: Interesting problem with instances
- Subject: Re: Interesting problem with instances
- From: Patrick Middleton <email@hidden>
- Date: Thu, 14 Dec 2006 12:16:06 +0000
On 14 Dec 2006, at 11:32, Guido Neitzer wrote:
Hi.
We have an application on one of our servers, that behaves very
strange.
Some instances don't load certain images from the database, other
instances do. I have compared the start parameters for the
instances and they are completely the same. They connect to the
same database (on a second server). They use the same binary
application package. They use the same JDBC driver.
Everything should be equal between the four instances but only
instance 1 and 4 are loading and displaying the images, 2 and 3 do
not display the images but show a message in the HTML:
<img src="/ERROR/NOT_FOUND/DYNAMIC_DATA">
while the "good" applications show:
<img src="/cgi-bin/WebObjects/DGA.woa/1/wr?
wodata=-2671207830510638622">
I don't know whether this makes any difference: this morning we
moved the database to a different server. Before that we had
everything on one server, now we moved the db (PostgreSQL 8.2 vs.
PostgreSQL 8.1.5) on a newer version on the new server. The new
server is an Intel Xserve which should replace the old server
completely and we started by moving the database. The test
application should no problems so we moved the production database
to the new server.
The database on the old server is off, so there is no way of
getting the data from somewhere else but the new server.
Interesting enough, other images are displayed without any problem
on the "bad" instances. Only some special images - and I currently
can't see what's special about that. This is another images fetched
from the bad instance:
<img src="/cgi-bin/WebObjects/DGA.woa/3/wr?
wodata=-6078072308583640953"></img>
So, there is no problem for the instance connecting to the images
database and getting content from there.
I have absolutely no idea what happens there.
Any idea about that? Any hint where I can look? Btw: I don't get
errors from that in the log.
cug
We use Sybase with WO451, and occasionally run into the following
problem: the client library has a default maximum transfer size for
BLOBs (text, image, other binary) of 32kB. EOF resets this to 2GB,
but command line tools such as isql and bcp don't; this means that
if we're not careful when migrating database data from database or
server to another, all the images get truncated at 32kB. This is not
a problem for some/most of our images that were less than 32kB in
size to start with. Nor is it a problem serverside for our WOApps --
they vend images as NSData, but we also still have some AppKit/EOF
desktop applications and it's a problem for them -- we don't use
+imageWithData: , we use a class method added via a category that
calls +imageWithData: but which catches the NEXTSTEP-style
NXException raised when reading a truncated tiff...
We're using WO451. I'm not sure what WO5 does here -- does it load
bytes, then use AWT or something to turn those bytes into an image?
So go looking at all your images, the good and the bad, and see how
long the data for each is in the database.
Remember also that WOResourceManager caches data -- if the app was
started while the database migration was still in progress, the row
required might have not been present when one instance tried to fetch
it and what you're seeing is "not found" from the cache, while
another instance may have tried to fetch it later and found and
returned it.
--
Patrick Middleton
OneStep Solutions plc
351 London Road Phone: +44 (0)1702 426400
Hadleigh Fax: +44 (0)1702 556855
Essex. SS7 2BT Email: email@hidden
England (MIME welcome)
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