UGA

The User Global Area (UGA) is a memory area (RAM) that holds session-based information.

Dedicated Server

When running in Dedicated Server mode (one session = one dedicated process), the UGA is stored in the PGA (process global area).

Shared Server

When running in Shared Server mode (MTS with shared servers and dispatchers), sessions can be served by multiple server processes. As a result, the UGA cannot be stored in the PGA, and is moved to the SGA (shared global area).

Monitoring the UGA

SELECT s.sid, n.name, s.value/power(1024,2) MB 
  FROM v$sesstat s, v$statname n
 WHERE s.statistic# = n.statistic#
   AND n.name LIKE '%uga%';

Also see

• Database Concepts and Architecture
• SGA and PGA

Glossary of Terms
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