Process and Runtime Limits

Instances per database

Maximum number of cluster database instances per database

Operating system-dependent

Locks

Row-level

Unlimited

Locks

Distributed Lock Manager

Operating system dependent

SGA size

Maximum value

Operating system-dependent; typically 2 to 4 GB for 32-bit operating systems, and > 4 GB for 64-bit operating systems

Advanced Queuing Processes

Maximum per instance

10

Job Queue Processes

Maximum per instance

1000

I/O Slave Processes

Maximum per background process (DBWR, LGWR, and so on)

15

I/O Slave Processes

Maximum per Backup session

15

Sessions

Maximum per instance

2¹⁶; limited by the PROCESSES and SESSIONS initialization parameters. 2¹⁶ is 65536.

Global Cache Service Processes

Maximum per instance

10

Shared Servers

Maximum per instance

Unlimited within constraints set by the PROCESSES and SESSIONS initialization parameters, for instance

Dispatchers

Maximum per instance

Unlimited within constraints set by PROCESSES and SESSIONS initialization parameters, for instance

Parallel Execution Slaves

Maximum per instance

Unlimited within constraints set by PROCESSES and SESSIONS initialization parameters, for instance

Backup Sessions

Maximum per instance

Unlimited within constraints set by PROCESSES and SESSIONS initialization parameters, for instance

Services

Maximum per instance

1024