Memory used by idle session

[becky]

Hi!

Is there a way to determine the amount of a host's system resources an orphan/zombie session is wasting in the DB? It seems a reporting tool we are using isn;t closing sessions

[NorbertKrupa]

The only way I could think of is to have global query profiling enabled, then match the statement from executing requests to the profile.

[scutter]

Idle sessions - as in not executing any statements? Idle sessions don’t use any memory. Memory is allocated at the start of query execution, and is released when the query completes. The idle session would count towards your MaxClientSessions maximum.

For determining memory being used by running queries, you can look in QUERY_REQUESTS (memory_acquired_mb) or RESOURCE_ACQUISITIONS (memory_inuse_kb) where is_executing.

—Sharon

[becky]

Thanks, guys! Scutter, you said:

Idle sessions don’t use any memory

It has to consume some memory, right? What about the session meta-data? Like the data (i.e. last_statement) in the sessions table itself. Doesn't that consume memory? If you multiply that small amount of memory usage by 100's of inactive sessions, I wonder if this can become an issue? Just curious.

I'm trying figure out how to make the Tableau server release connections to Vertica even after logging out of a workbook. Note that this isn't an issue with Vertica