I was doing test on lsm with "type=lsm, key_format=r, value_format=S", after some insertion, lsm_merge triggered, and panic occurred around
> https://github.com/wiredtiger/wiredtiger/blob/master/src/lsm/lsm_merge.c#L537

> [1506341229:102488][25424:0x7fffef6a8700], file:bucket64-000010.lsm, lsm-worker: unable to read root page from file:bucket64-000010.lsm: WT_ERROR: non-specific WiredTiger error
> [1506341229:114665][25424:0x7fffef6a8700], lsm-worker: Error in LSM worker thread 2: WT_ERROR: non-specific WiredTiger error
> [1506341229:114706][25424:0x7fffef6a8700], lsm-worker: the process must exit and restart: WT_PANIC: WiredTiger library panic
> [Thread 0x7fffef6a8700 (LWP 25446) exited]

hence i wondered, if LSM doesn't support key_format = 'r' ?

Thanks