I spent last week entirely on one issue: CDV-244 (and it’s duplicate CDV-736, which someone raised recently on a forum). I got a lot of coding done, but ultimately did not yet fix the issue. This week I need to put that aside and do some performance testing, my team owes marketing some comparative testing between versions 2.5 and 2.6 of Terracotta. So, it was another frustrating week of not actually finishing anything.

The issue itself is interesting. Serializing an object in the L1 which is not fully faulted into memory can fail if the serialization uses sun.misc.Unsafe.getObject(Object, long), which is a native method and which bypasses all of our bytecode instrumentation magic. Our solution, which is becoming somewhat of a pattern with native methods, is twofold: (1) use instrumentation to create a new wrapper method within Unsafe, called __tc_getObject, which does all of the necessary resolution of the Object arg if it is clustered, and (2) instrument any and all instrumented code which calls the original native method to call this instead. (This is similar to the way we tackled String.intern(), another native method.)

Our product manager Taylor wrote a nice simple TIM which reproduced the issue. I took that and modified it so that I could step through using Eclipse’s debugger. I also came up with one of our automated system tests which currently fails, and which I hope will prove the fix works, once the fix is done. At this point I’ve got a fix that I think should work, but the boot jar tool complains about the boot jar being invalid during startup. I’ve decompiled and tested the instrumented copy of Unsafe from within the boot jar and it is fine, so I’m not yet sure what the problem is.

Friday was the last day for my teammate Antonio, who has accepted a job with NASA. We are extremely sorry to see him go. He has been on the team for some time, he knows a lot, and has done tons of great coding. He is very smart, works hard and is a nice guy. Good luck in space, Antonio!