How do I reduce UWC memory usage when converting large site from Twiki?

[Bruce Cran]

I'm attempting to use UWC to convert a large site from Twiki. The problem is it has lots of attachments and while it's going through the stage where it prints "attachment written" the memory usage is rather ridiculous: it appears to want over 24 GB: it pushes my machine which has 12 GB RAM over 12 GB into swap. Is there any way to reduce the amount of memory UWC needs, or do I just need to have plenty of swap space allocated and let it run

[Laura Kolker · Accepted solution]

Hi Bruce,

Reposting the important bits from my answer from the old forum here for doc purposes.

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So there are two ways to upload attachments:

1. Xmlrpc (default), which requires 4x as much memory as the size of the attachment
2. Webdav plugin, which requires less memory, although I can't give you so nicely specific a figure.

If you want to try using that feature, details here: UWC Webdav Attachments. Only downside I've run into is if your attachments have problematic names (like with question marks), then the upload can fail on that attachment.

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Oh, and one other thought:

If you end up having to increase the memory you've given to your tomcat (which might be a good idea), you probably want to up the memory on the Confluence as opposed to the UWC itself (which you can do as well - let me know if you need instructions for that).

Cheers,

Laura

[Laura Kolker]

@Tyler re: Sounds like it's reading all the attachments into memory prior to shoving them into the Confluence system.

I could be wrong, but I do not think this is happening. As far as I can see it's just making the xmlrpc call, and it would be doing it one attachment at a time. If anyone wants to take a peak at the relevant code it's here: https://studio.plugins.atlassian.com/source/browse/UWC/devel/src/com/atlassian/uwc/ui/ConverterEngine.java?hb=true#to1366

[Leandro Nunes]

Hi Bruce,

UWC has a FAQ and one question called my attention:

I have a very large wiki to convert. Are there any gotchas I should look out for?

http://confluence.fangwai.net/display/CONFEXT/UWC+F.A.Q.#UWCF.A.Q.-Ihaveaverylargewikitoconvert.ArethereanygotchasIshouldlookoutfor%3F

Hope this helps you!

[TylerA]

Sounds like it's reading all the attachments into memory prior to shoving them into the Confluence system. Did you set Confluence/Twiki to store your attachments in the DB or does it store the attachments in the filesystem?