nbari / pg_exporter / 34328014958

90%

main: 90%

Build Type

push

github

Committed by nbari

Commit Message

Fix process-group memory counting shared_buffers once per backend

The default rss source summed statm resident pages across all postgres
processes, so shared_buffers was charged to every backend that touched
it: 312 GiB reported on a 93.8 GiB host with 208 backends (issue #36).

Read resident minus shared from the same statm line instead, so the
gauge reports the group's private memory — the part that actually grows
with work_mem, sorts and hash joins. Same single read per process, same
O(processes) cost, and the pss opt-in keeps working with the private
figure as its fallback.

Also update the CLI help, collector docs, Grafana panel and legend to
describe the private-memory semantics, and add the 0.20.0 changelog
entry noting the remaining FreeBSD limitation.

Fix #36

Coverage Stats

21 of 23 new or added lines in 2 files covered. (91.3%)

15 existing lines in 5 files now uncovered.

19940 of 22190 relevant lines covered (89.86%)

485.8 hits per line