TYPO3 Core

I've posted this on the dev list before and cannot get to the bottom of it. The problem seems to erratically go away and come back again.

Sometimes, I get connection problems in the workspace module when I try reading the changes for a page. I've investigated this from the server side and found that incomplete JSON arrays are being sent. While the content length in the header seems correct, the content is truncated about half way.

At first it seemed this only happened when the server was under heavy load. However, testing that longer term, did not confirm that suspicion. Doubling the memory available to PHP also did not fix the problem.

No Apache, system, MySQL or PHP logs show any errors in conjunction with this phenomenon. The timeouts are extremely long (15min), all resource limits should be more than plenty. I've also had this problem on two different servers with the same site. One ran Gentoo x86 Linux and the other one Debian Squeeze.

I have been unable to work out a pattern when this issue arises and when it doesn't. It also often does not affect all pages at once but often only applies to a seemingly arbitrary subset of pages.

I'm happy to contribute more findings if anyone has hints what else to try.