The OOM killer, a feature enabled by default, is a self-protection mechanism employed the Linux kernel when under severe memory pressure.
If the kernel cannot find memory to allocate when it’s needed, it puts in-use user data pages on the swap-out queue, to be swapped out. If the Virtual Memory (VM) cannot allocate memory and cannot swap out in-use memory, the Out-of-memory killer may begin killing current userspace processes. it will sacrifice one or more processes in order to free up memory for the system when all else fails.
Apr 1 00:01:02 srv01 kernel: Out of Memory: Killed process 2592 (oracle).
his means that the OOM killer has killed the oracle dedicated server process 2592.