repro memory leak under pg_stat_monitor #182
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To do this execute in one terminal: ```bash xpg -v 15 psql ``` And this in another: ```bash watch -n 1 'ps -p $(cat build-15/bgworker.pid) -o %mem,rss,vsz,comm' %MEM RSS VSZ COMMAND 0.1 19164 722508 postgres ``` The RSS should be seen as always growing, which proves the memory leak.
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Problem
When adding
pg_stat_monitorlike:Memory usage keeps increasing for the pg_net background worker.
To prove this execute in one terminal:
And this in another:
watch -n 1 'ps -p $(cat build-15/bgworker.pid) -o %mem,rss,vsz,comm' %MEM RSS VSZ COMMAND 0.1 19164 722508 postgresThe RSS should be seen as always growing, which proves the memory leak.
Root cause
pg_stat_monitor statistics are split into configurable time intervals (buckets). As one bucket fills or a time interval passes, pg_stat_monitor creates a new one, keeping historical data in distinct buckets.
pg_net queries its internal tables each second.
This means that the "memory leak" is actually expected behavior by pg_stat_monitor.
We need to fix this in pg_net itself, by doing #164.