How do I change heap memory settings when CF won't start?

[BreakawayPaul]

I'm in the process of re-writing a web app that someone else did a very poor job on, especially the database design.

While examining the existing database, I ran into an "OutOfMemoryError: Java heap space" error, so I went into the CF Admin and bumped the setting from 512 up to 2048 (CF8 Developer Edition).

Now I can't get CF to start up, and as such I can't get back into the CF Admin to change the setting back.  Is there any way to fix this without reinstalling CF?

[REEDPOWELL · Accepted solution]

It's somewhat version and edition dependent, so just open a CMD window, CD to the base of your installation (C:\ColdFusion9 for instance) and dir a DIR/S jvm.config to find the config file.  Then just open it in notebook, etc., and fix the memory setting.

-reed

[BreakawayPaul]

Reed, you are a gentleman and a scholar.  My system is back up, thank you!

[DCwebGuy]

First of all, if you are running on a 32-bit system, nothing over 1024 will work, and will in fact crash the machine.  As the person above mentioned, you can simply stop your CF services, modify the jvm.config manually, and restart.  If you are on 64-bit please let us know.

P.S.  Even bumping up from 512 to 1024 should make a big difference.  And you may also want to increase your maxPermSize to the next 128m increment.  On a 32-bit system, always make changes incrementally and test.  And plan to upgrade to 64-bit if you are not already.

[REEDPOWELL]

Not true.  You can easily go as high as at least 1384 on a 32 bit system.  I usually run into problems going any higher, although the memory architecture would allow it to go to around 1.8gb.

-reed

[DCwebGuy]

That may be true, but 1024 is a more efficient and common chunk size.  It's usually best practice to open up memory in chunks of 128/256/512/1024 and so on.  To be honest I've never tested the difference, but you can Google it.  If you're so desperate that you need the additional 360mb then go for it, but it seems dangerous to me to run at exactly the "redline".  Plus, you'll need to make sure the rest of the programs running on the 32-bit system have enough memory of their own or you could run into page caching issues that will slow things down indirectly.  Or you could try implementing the /3G startup switch in Windows server, I had to do that once.