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Why Are Oracle User Processes In One Database Consuming More Memory As Compared To A Different Database? (Doc ID 1676789.1)

Last updated on FEBRUARY 18, 2019

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 10.2 to 12.1]
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Information in this document applies to any platform.


Why are Oracle User Processes in one database (PROD) consuming more memory as compared to a different database (DEV)?

The same Oracle version is used on both PROD and PTE databases.  The Linux servers have the same configuration. The memory difference is observed at the connection time.

PROD - UGA and PGA allocation at the connection time:

618536 session uga memory(21)
873024 session uga memory max(22)
1287944 session pga memory(26)
1484552 session pga memory max(27)

DEV - UGA and PGA allocation at the connection time:

291096 =session uga memory(21)
291096= session uga memory max(22)
632584=session pga memory(26)
632584=session pga memory max(27)

At the OS level, the output for " cat /proc/<pid>/maps" where pid= process id associated with a new Oracle session.


VmPeak: 42094588 kB
VmSize: 4476924 kB
VmLck:       0 kB
VmHWM:  218360 kB
VmRSS:  218360 kB
VmData:    1844 kB
VmStk:      92 kB
VmExe:  102844 kB
VmLib:   16208 kB
VmPTE:    1200 kB
StaBrk: 15339000 kB


VmPeak: 30554668 kB
VmSize:  143916 kB
VmLck:       0 kB
VmHWM:   24144 kB
VmRSS:   24144 kB
VmData:    1836 kB
VmStk:     216 kB
VmExe:   96236 kB
VmLib:   16208 kB
VmPTE:     292 kB
StaBrk: 1619c000 kB

The top output from PROD shows :



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