Memory usage reporting

Vertica periodically polls its own memory usage to determine whether it is below the threshold that is set by configuration parameter MemoryPollerReportThreshold.Polling occurs at regular intervals—by default, every 2 seconds—as set by configuration parameter MemoryPollerIntervalSec.

The memory poller compares MemoryPollerReportThreshold with the following expression:

RSS / available-memory

When this expression evaluates to a value higher than MemoryPollerReportThreshold—by default, set to 0.93, then the memory poller writes a report to MemoryReport.log, in the Vertica working directory. This report includes information about Vertica memory pools, how much memory is consumed by individual queries and session, and so on. The memory poller also logs the report as an event in system table MEMORY_EVENTS, where it sets EVENT_TYPE to MEMORY_REPORT.

The memory poller also checks for excessive glibc allocation of free memory (glibc memory bloat). For details, see Memory trimming.