Resident Set Size Increases in Excess of mem Database Option Setting
Symptom
There is a slow but steady increase in Resident Set Size (RSS) in excess of the mem database option setting in NuoDB Storage Manager (SM) or Transaction Engine (TE) processes.
Cause
The Transparent Huge Pages (THP) Linux kernel feature is enabled. NuoDB, like many other long-running and memory-intensive services, is not able to manage its memory well when THP is enabled.
| If the NuoDB database process can determine that THP is enabled when it starts, it will refuse to start. |
Some systems may be configured such that NuoDB processes do not have sufficient permissions to determine the state of THP. In this situation the NuoDB process will assume that THP is not enabled and will start, writing a warning similar to Cannot determine if Linux kernel transparent hugepage support is enabled to the NuoDB Admin log file. If THP is enabled, then you may see this symptom.