oracle中容易忽略的後臺程式

Name

Expanded Name

Short Description

Long Description

External Properties

DIA0

Diagnostic Process

Detects and resolves hangs and deadlocks

ASM and Database instances

DIAG

Diagnostic Capture Process

Performs diagnostic dumps

DIAG performs diagnostic dumps requested by other processes and dumps triggered by process or instance termination. In Oracle RAC, DIAG performs global diagnostic dumps requested by remote instances.

ASM and Database instances

GTXn

Global Transaction Process

Provides transparent support for XA global transactions in an Oracle RAC environment

These processes help maintain the global information about XA global transactions throughout the cluster. Also, the processes help perform two-phase commit for global transactions anywhere in the cluster so that an Oracle RAC database behaves as a single system to the externally coordinated distributed transactions.

The GLOBAL_TXN_PROCESSES initialization parameter specifies the number of GTXn processes, where n is 0-9 or a-j. The database automatically tunes the number of these processes based on the workload of XA global transactions. You can disable these processes by setting the parameter to 0. If you try to run XA global transactions with these process disabled, an error is returned.

See Also:

Database instance, Oracle

LCK0

Instance Enqueue Background Process

Manages global enqueue requests and cross-instance broadcasts

The process handles all requests for resources other than data blocks. For examples, LCK0 manages library and row cache requests.

Database and ASM instances, Oracle RAC

LMHB

Global Cache/Enqueue Service Heartbeat Monitor

Monitor the heartbeat of LMON, LMD, and LMSn processes

LMHB monitors LMON, LMD, and LMSn processes to ensure they are running normally without blocking or spinning.

Database and ASM instances, Oracle RAC

MMAN

Memory Manager Process

Serves as the instance memory manager

This process performs the resizing of memory components on the instance.

Database and ASM instances

MMNL

Manageability Monitor Lite Process

Performs tasks relating to manageability, including active session history sampling and metrics computation

MMNL performs many tasks relating to manageability, including session history capture and metrics computation.

Database and ASM instances

MMON

Manageability Monitor Process

Performs or schedules many manageability tasks

MMON performs many tasks related to manageability, including taking Automatic Workload Repository snapshots and performing Automatic Database Diagnostic Monitor analysis.

Database and ASM instances

RECO

Recoverer Process

Resolves distributed transactions that are pending because of a network or system failure in a distributed database

RECO uses the information in the pending transaction table to finalize the status of in-doubt transactions. At timed intervals, the local RECO attempts to connect to remote databases and automatically complete the commit or rollback of the local portion of any pending distributed transactions. All transactions automatically resolved by RECO are removed from the pending transaction table.

See Also: and

Database instance