| General Information |
| Notes |
Unlike most of the library pages which are full of live demos this page is intended as a repository into which I will collect,
over time, the best advice I find with respect to various Oracle processes. Some of the entries, below, are placeholders for when I find things of more interest.
If you can find a link to something you think worth sharing with the community please send it in.
The basic template I am using to create this page is this
Oracle Doc.
~ Thank you. |
| To find active processes in your instance that may be on this page |
SELECT inst_id, program
FROM gv$session
WHERE service_name = 'SYS$BACKGROUND'
ORDER BY 1,2; |
| |
| ABMR |
| Auto BMR Background |
Coordinates execution of tasks such as filtering duplicate block media recovery requests and flood control |
| TBD |
| |
| ACFS |
| ASM Cluster File System CSS |
Tracks CSS cluster membership and informs the file system driver of membership changes |
| TBD |
| |
| ACMS |
| Atomic Controlfile to Memory Service |
Coordinates consistent control file resource updates to a with its SGA counterpart on all instances in a RAC cluster.
Works with a coordinating caller to ensure that an operation is executed on every cluster instance despite possible failures.
ACMS is the process in which a distributed operation is called. As a result, this process can exhibit a variety of behaviors.
In general, ACMS is limited to small, non-blocking state changes for a limited set of cross-instance operations. |
| Real Application Clusters (RAC) |
| |
| APnn |
| Logical Standby / Streams Apply Process Coordinator |
Obtains transactions from the Streams reader server and passes them to the Streams apply servers |
| Morgan's Library Link |
| |
| ARBn |
| ASM Rebalance Process |
Rebalances data extents within an ASM disk group |
| TBD |
| |
| ARCn |
| Archiver |
Creates archive copies of redo log files when they are full or an online redo log switch occurs.
ARCn processes exist only when the database is in ARCHIVELOG mode and automatic archiving is enabled.
LGWR cannot reuse/overwrite an online redo log group until it has been archived.
The database can start multiple archiver processes as needed to ensure that the archiving of filled online redo logs does not fall behind.
Possible processes include ARC0-ARC9 and ARCa-ARCt. The LOG_ARCHIVE_MAX_PROCESSES initialization parameter specifies the number of ARC
n processes that the database initially invokes: Not the maximum number of possible processes. |
| Morgan's Library Link |
| |
| ASMB |
| ASM Background |
Communicates with the ASM instance, managing storage and providing statistics.
ASMB runs in ASM instances when the ASMCMD cp command runs or when the database instance first starts if the server parameter file is stored in ASM.
ASMB also runs with Oracle Cluster Registry on ASM. |
| TBD |
| |
| ASnn |
| Logical Standby / Streams Apply Process Reader Server or Apply Server |
With Streams, when the reader server finishes computing dependencies between LCRs and assembling transactions,
it returns the assembled transactions to the coordinator process:
Query V$STREAMS_APPLY_READER for information about the reader server background process.
An apply server receives the transactions from the coordinator background process,
and either applies database changes in LCRs or sends LCRs or messages to apply handlers.
Apply servers can also enqueue a queue. If an apply server encounters an error,
then it then tries to resolve the error with a user-specified conflict handler or error handler.
If an apply server cannot resolve an error, then it rolls back the transaction and places the entire transaction,
including all of its messages, in the error queue. When an apply server commits a completed transaction,
this transaction has been applied. When an apply server places a transaction in the error queue and commits,
this transaction also has been applied. Query V$STREAMS_APPLY_SERVER for information about the apply server background process.
The coordinator process name is ASnn, where nn can include both letters and numbers. |
| Morgan's Library Link |
| |
| BMRn |
| Automatic Block Media Recovery Slave Pool |
When a process submits a block media recovery request to ABMR,
it dynamically spawns slave processes (BMRn) to perform the recovery.
BMRn processes fetch blocks from a real-time readable standby database. ABMR and BMRn terminate if idle for a long time. |
| Morgan's Library Link |
| |
| Bnnn |
| ASM Blocking Slave for GMON |
Performs actions that require waiting for resources on behalf of GMON.
A Bnnn slave is spawned when an ASM disk is taken offline.
The Off-line timer processing and disk drop are performed in this slave. Up to five process (B000 to B004) can exist depending on the load. |
| TBD |
| |
| CJQ0 |
| Job Queue Coordinator |
Selects jobs that need to be run from the data dictionary and spawns job queue slave processes
(Jnnn) to run the jobs. This process is automatically started and stopped as needed by the Scheduler.
The JOB_QUEUE_PROCESSES initialization parameter specifies the maximum number of processes that can be created for job executions.
CJQ0 starts only as many job queue processes as required by the number of jobs to run and available resources. |
| Morgan's Library Link |
| |
| CKPT |
| Checkpointer |
At specific times CKPT starts a checkpoint request by messaging DBWn to begin writing dirty buffers.
On completion of individual checkpoint requests, CKPT updates data file headers and control files to record the most recent checkpoint. |
| TBD |
| |
| CPnn |
| Streams Capture |
Captures database changes from the redo log with LogMiner utilizing one reader server that reads the redo log
and divides it into regions, one or more preparer servers that scan the redo log,
and one builder server that merges redo records from the preparer servers. Each reader server, preparer server, and builder server is a separate process.
Query the V$STREAMS_CAPTURE view for information about this background process.
The capture process name is CPnn, where nn can include letters and numbers.
The underlying LogMiner process name is MSnn, where nn can include letters and numbers. |
| Morgan's Library Link |
| |
| CSnn |
| Streams Propagation Sender |
Sends LCRs to a propagation receiver. In an Oracle Streams combined capture and apply optimization,
the propagation sender sends LCRs directly to the propagation receiver to improve performance. The propagation receiver passes the LCRs to an apply process.
Query V$PROPAGATION_SENDER for information about a propagation sender. |
| Morgan's Library Link |
| |
| CSnn |
| I/O Calibration |
Slave processes are started on execution of the DBMS_RESOURCE_MANAGER.CALIBRATE_IO procedure with one slave process per CPU per instance. |
| Morgan's Library Link |
| |
| CTWR |
| Block Change Tracking Writer |
CTWR tracks changed blocks as redo is generated at a primary database and as redo is applied at a standby database.
The process is slightly different depending on the type of database.
Buffer size can be configured with a number of undocumented parameter listed here in the Undocumented Parameters section. |
| Morgan's Library Link |
| |
| DBRM |
| Database Resource Manager |
Only active if a resource plan is enabled: Sets resource plans and performs other tasks related to the Database Resource Manager. |
| Morgan's Library Link |
| |
| DBWn |
| Database Writers |
Writes modified blocks from the database buffer cache to the data files on disk.DBWn also writes checkpoints, manages file open synchronization, and the logging of Block Written records.
DBWn performs multiblockwrites when possible to improve efficiency but because it's writes are scattered throughout the disk
they are usually slower than the sequential writes performed by LGWR. The number of blocks written in a multiblock write varies by operating system.
The DB_WRITER_PROCESSES initialization parameter specifies the number of DBWn processes (DBW0-DBW9 and DBWa-DBWz).
The database selects an appropriate default setting for this parameter or adjusts a user-specified setting based on the number of CPUs and processor groups. |
Learn How To Obliterate Processor Caches: Configure Lots and Lots of DBWR Processes. Part 1.
Over-configuring DBWR Processes. Part II
Over-configuring DBWR Processes. Part III
Over-configuring DBWR Processes. Part IV |
| |
| DIA0 |
| Hang detection diagnostic process |
Detects and aids in resolving hangs and deadlocks |
| TBD |
| |
| DIAG |
| Diagnostic Capture |
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. |
| Morgan's Library Link |
| |
| DMnn |
| DataPump |
Coordinates the Data Pump job tasks performed by Data Pump worker processes and handles client interactions.
The Data Pump master (control) process is started during job creation and coordinates all tasks performed by the Data Pump job.
It handles all client interactions and communication, establishes all job contexts, and coordinates all worker process activities on behalf of the job. |
| Morgan's Library Link |
| |
| DMON |
| Data Guard Broker Monitor |
Manages and monitors a database that is part of a Data Guard broker configuration.
When you start the Data Guard broker, a DMON process is created. DMON runs for every database instance that is managed by the broker.
DMON interacts with the local database and the DMON processes of the other databases to perform the requested function.
DMON also monitors the health of the broker configuration and ensures that every database has a consistent description of the configuration.
DMON maintains profiles about all database objects in the broker configuration in a binary configuration file.
A copy of this file is maintained by the DMON process for each of the databases that belong to the broker configuration.
The process is created when the DG_BROKER_START initialization parameter is set to true. |
| Morgan's Library Link |
| |
| Dnnn |
| Dispatcher |
Performs network communication in the shared server architecture.
In the shared server architecture, clients connect to a dispatcher process, which creates a virtual circuit for each connection.
When the client sends data to the server, the dispatcher receives the data into the virtual circuit and places the active circuit
on the common queue to be picked up by an idle shared server. The shared server then reads the data from the virtual circuit and
performs the database work necessary to complete the request. When the shared server must send data to the client, the server
writes the data back into the virtual circuit and the dispatcher sends the data to the client.
After the shared server completes the client request, the server releases the virtual circuit back to the dispatcher and is free to handle other clients.
Several initialization parameters relate to shared servers.
The principal parameters are: DISPATCHERS, SHARED_SERVERS, MAX_SHARED_SERVERS, LOCAL_LISTENER, REMOTE_LISTENER. |
| TBD |
| |
| DRnn |
| ASM Disk Resynchronization Slave |
Resynchronizes the contents of an offline disk.
When a disk online SQL command is issued on a disk or disks that are offline, ASM spawns DRnn. Depending on the load, more than one slave may be spawned. |
| TBD |
| |
| DSKM |
| Dismon Slave |
Conduit between the database, ASM instances, and the Master Diskmon daemon to communicate information to Exadata storage.
This process is active only if Exadata Storage is used. DSKM performs operations related to Exadata I/O fencing and Exadata cell failure handling. |
| TBD |
| |
| DWnn |
| DataPump Worker |
Performs Data Pump tasks as assigned by the Data Pump master process.
The Data Pump worker process is responsible for performing tasks that are assigned by the Data Pump master process,
such as the loading and unloading of metadata and data. |
| Morgan's Library Link |
| |
| EMNC |
| Emon Coordinator |
Coordinates event management and notification activity in the database, including Streams Event Notifications,
Continuous Query Notifications, and Fast Application Notifications. |
| Morgan's Library Link |
| |
| Ennn |
| Emon Slave |
The database event management and notification load is distributed among the EMON slave processes.
These processes work on the system notifications in parallel, offering a capability to process a larger volume of notifications,
a faster response time, and a lower shared memory use for staging notifications. |
| Morgan's Library Link |
| |
| FBDA |
| Flashback Data Archiver |
This technology is part utilized by Flashback Archive marketed by Oracle as "Total Recall."
When a transaction that modifies a tracked table commits, FBDA stores the pre-image of the rows in the archive.
FDBA maintains metadata on the current rows and tracks how much data has been archived.
FBDA is also responsible for automatically managing the flashback data archive for space, organization (partitioning tablespaces), and retention.
FBDA also keeps track of how far the archiving of tracked transactions has progressed. |
| Morgan's Library Link |
| |
| FMON |
| File Mapping Monitor |
The DBMS_STORAGE_MAP package enables control of the mapping operations. When instructed by the user,
FMON builds mapping information and stores it in the SGA, refreshes the information when a change occurs,
saves the information to the data dictionary, and restores it to the SGA at instance startup.
FMON is started by the database whenever the FILE_MAPPING initialization parameter is set to true. |
| Morgan's Library Link |
| |
| FSFP |
| Data Guard Broker Fast Start Failover Pinger |
This process is created when Fast Start Failover is enabled |
| Morgan's Library Link |
| |
| GCRn |
| Global Conflict Resolution Slave Process |
Transient slaves started and stopped as required by LMHB to perform synchronous or resource intensive tasks |
| TBD |
| |
| GEN0 |
| General Task Execution Monitor |
Performs required tasks including SQL and DML |
| TBD |
| |
| GMON |
| ASM Disk Group Monitor |
Monitors all disk groups mounted in an ASM instance and is responsible for maintaining consistent disk membership and status information.
Membership changes result from adding and dropping disks, whereas disk status changes result from taking disks offline or bringing them online.
Calls Bnnn slaves to perform the work. |
| TBD |
| |
| GTXn |
Global Transaction
Supports global XA transactions with RAC |
These processes help maintain the global information about XA global transactions throughout the cluster.
They support global transaction two phase commit anywhere in the cluster so that an Oracle RAC database behaves as a single system to
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. |
| Morgan's Library Link |
| |
| Innn |
| Disk and Tape I/O Slave |
I/O slave process can be configured on platforms where asynchronous I/O support is not available.
These slaves are started by setting the corresponding slave enable parameter in the server parameter file.
The I/O slaves simulate the asynchronous I/O behavior when the underlying platform does not have native support for asynchronous I/O. |
| TBD |
| |
| INSV |
| Data Guard Broker Instance Slave |
INSV is created when the DG_BROKER_START initialization parameter is set to true. |
| Morgan's Library Link |
| |
| Jnnn |
| Job Queue Slave |
Job slave processes are created or awakened by the job coordinator when it is time for a job to be executed.
Job slaves gather all the metadata required to run the job from the data dictionary. The slave processes start a database session as the owner of the job,
execute triggers, and then execute the job. After the job is complete, the slave processes commit and then execute appropriate triggers and close the session.
The slave can repeat this operation in case additional jobs need to be run. |
| Morgan's Library Link |
| |
| LCK0 |
Instance Enqueue Background
Global enqueue and cross-instance broadcast |
The process handles all requests for resources other than data blocks. For examples, LCK0 manages library and row cache requests. |
| Morgan's Library Link |
| |
| LGWR |
| Log Writer |
Redo log entries are generated in the redo log buffer of the system global area (SGA).
LGWR writes the redo log entries sequentially into a redo log file.
If the database has a multiplexed redo log, then LGWR writes the redo log entries to a group of redo log files. |
| Morgan's Library Link |
| |
| LMD0 |
| Global Enqueue Service Daemon 0 |
LMD0 processes enqueue resources managed under Global Enqueue Service.
In particular, LMD0 processes incoming enqueue request messages and controls access to global enqueues. It also performs distributed deadlock detections. |
| Morgan's Library Link |
| |
| LMHB |
| Global Cache/Enqueue Service Hearbeat |
LMHB monitors LMON, LMD, and LMSn processes to ensure they are running normally without blocking or spinning. |
| Morgan's Library Link |
| |
| LMON |
| Global Enqueue Service Monitor |
LMON maintains instance membership within Oracle RAC.
The process detects instance transitions and performs reconfiguration of GES and GCS resources. |
| Morgan's Library Link |
| |
| LMSn |
Global Cache Service
Resource control with RAC instances |
LMS, where n is 0-9 or a-z, maintains a lock database for Global Cache Service (GCS) and buffer cache resources.
This process receives, processes, and sends GCS requests, block transfers, and other GCS-related messages. |
| Morgan's Library Link |
| |
| LSP0 |
| Logical Standby Coordinator |
LSP0 is the initial process created upon startup of Data Guard SQL Apply.
In addition to managing LogMiner and Apply processes, LSP0 is responsible for maintaining inter-transaction
dependencies and appropriately scheduling transactions with applier processes.
LSP0 is also responsible for detecting and enabling runtime parameter changes for the SQL Apply product as a whole. |
| Morgan's Library Link |
| |
| LSP1 |
| Logical Standby Dictionary Build |
The LSP1 process is spawned on a logical standby database that is intended to become the new primary database.
A logical standby database becomes a primary database by means of switchover or failover.
The dictionary is necessary for logical standby databases to interpret the redo of the new primary database. |
| Morgan's Library Link |
| |
| LSP2 |
Logical Standby Set Guard
Determines which objects will be protected |
The LSP2 process is created as needed during startup of SQL Apply to update the list of objects that are protected by the database guard. |
| Morgan's Library Link |
| |
| Lnnn |
Pooled Server
Manages client requests in database resident connection pooling |
In Database Resident Connection Pooling, clients connect to a connection broker process.
When a connection becomes active, the connection broker hands off the connection to a compatible pooled server process.
The pooled server process performs network communication directly on the client connection and processes requests until the client releases the server.
After being released, the connection is returned to the broker for monitoring, leaving the server free to handle other clients. |
| Morgan's Library Link |
| |
| MARK |
| Mark AU for Resynchronization Coordinator.
Marks ASM allocation units as stale |
MARK essentially tracks which extents require resynchronization for offline disks.
This process runs in the database instance and is started when the database instance first begins using the ASM instance.
If required, MARK can also be started on demand when disks go offline in the ASM redundancy disk group. |
| TBD |
| |
| MMAN |
| Memory Manager |
Performs instance memory component resizing |
| TBD |
| |
| MMNL |
| Manageability Monitor Lite |
Performs multiple manageability related tasks including session history capture and metrics computation |
| TBD |
| |
| MMON |
| Manageability Monitor |
Performs multiple manageability tasks including taking AWR snapshots and ADDM analysis |
| Morgan's Library Link |
| |
| Mnnn |
| MMON Slave |
Performs manageability tasks dispatched to them by MMON |
| Morgan's Library Link |
| |
| MRP0 |
| Physical Data Guard Managed Standby Recovery |
Spawned at the start of redo apply on a Data Guard physical standby.
MRP0 handles the extraction and coordinates the application of redo on the physical standby |
| Morgan's Library Link |
| |
| MSnn |
| Log Miner Worker |
Multiple MSnn processes can exists, where n is 0-9 or a-Z.
A minimum of three MSnn processes work as a group to provide transactions to a LogMiner client, for example, a logical standby database.
There may be more than one such group, for example, Downstream Capture sessions. |
| Morgan's Library Link |
| |
| Nnnn |
| Connection Broker |
In Database Resident Connection Pooling, clients connect to a connection broker process.
When a connection becomes active, the connection broker hands off the connection to a compatible pooled server process.
The pooled server process performs network communication directly on the client connection and processes requests until the client releases the server.
After being released, the connection is returned to the broker for monitoring, leaving the server free to handle other clients. |
| Morgan's Library Link |
| |
| NSAn |
| Redo Transport NSA1 |
As part of Data Guard: NSAn can run as multiple processes,
where n is 1-9 or A-V that ship redo from current online redo logs to standby destinations when configured for ASYNC transport |
| Morgan's Library Link |
| |
| NSSn |
Redo Transport NSS1
SYNC transport LGWR Slave |
Acts as a slave for LGWR when SYNC transport is configured for a remote standby destination |
| Morgan's Library Link |
| |
| NSVn |
Data Guard Broker NetSlave
Broker network communications |
Created when a Data Guard broker configuration is enabled.
There can be as many NSVn processes (where n is 0- 9 and A-U) created as there are databases in the Data Guard broker configuration. |
| Morgan's Library Link |
| |
| OCFn |
| ASM CF Connection Pool |
Maintains a connection to the ASM instance for metadata related operations |
| TBD |
| |
| Onnn |
| ASM Connection Pool |
Slave processes spawned on demand to communicate with an ASM instance |
| TBD |
| |
| PING |
| Interconnect Latency Measurement |
Every few seconds, the process in one instance sends messages to each cluster instance.
The message is received by PING on the target instance and the round trip time measured and collected |
| Morgan's Library Link |
| |
| PMON |
| Process Monitor |
PMON periodically performs cleanup of all the following:
- Processes that died abnormally
- Sessions that were killed
- Detached transactions that have exceeded their idle timeout
- Detached network connections which have exceeded their idle timeout
In addition, PMON monitors, spawns, and stops the following as needed:
- Dispatcher and shared server processes
- Job queue processes
- Pooled server processes for database resident connection pooling
- Restartable background processes
PMON is also responsible for registering information about the instance and dispatcher processes with the network listener.
|
| TBD |
| |
| Pnnn |
| Parallel Query Slave |
Parallel Query has two components: a foreground process that acts as query coordinator and a set of parallel slaves (Pnnn)
that are background processes. These background processes are spawned or reused during the start of a parallel statement.
They receive and carry out units of work sent from the query coordinator.
The maximum number of processes is controlled by the PARALLEL_MAX_SERVERS initialization parameter.
Slave processes are numbered from 0 to the value of the initialization parameter PARALLEL_MAX_SERVERS.
If the query is a GV$ query, then these background processes are numbered backward, beginning with PZ99, then PZ98, etc. |
| TBD |
| |
| PRnn |
| Parallel Recovery |
A slave for the coordinator process performing parallel media recovery carrying out tasks assigned by the coordinator.
The default number of these processes is based on number of CPUs. Parallel recovery sessions can be found in the gv$px_session dynamic performance view. |
| Morgan's Library Link |
| |
| PSP0 |
| Processor Spawner |
After startup spawns background processes |
| TBD |
| |
| QMNC |
| AQ Coordinator |
Responsible for facilitating various background activities required by AQ and Streams such as management of messages,
non-persistent queues, and resource cleanup. Also dynamically spawns Qnnn slave processes as required.
Note that if the AQ_TM_PROCESSES initialization parameter is set to 0, this process will not start.
The database writes the following message to the alert log: "WARNING: AQ_TM_PROCESSES is set to 0. System might be adversely affected." |
| Morgan's Library Link |
| |
| Qnnn |
| AQ Coordinator (QMNC) Slave |
Slave processes initiated by QMNC |
| Morgan's Library Link |
| |
| RBAL |
| ASM Rebalance Master |
In an ASM instance, coordinates disk group rebalance |
| TBD |
| |
| RCBG |
| Result Cache Background |
Handles invalidations and other messaging generated by server processes attached to other instances in a RAC cluster |
| Morgan's Library Link |
| |
| RECO |
| Recoverer |
Uses the information in the pending transaction table to finalize the status of in-doubt transactions.
At timed intervals, the local RECO process attempts to connect to remote databases and commit or rollback of the local portion of any pending distributed transactions.
All transactions resolved by RECO are removed from the pending transaction table. |
| TBD |
| |
| RMSn |
| RAC Management |
Performs a variety of tasks, including creating resources related to Oracle RAC when new instances are added to a cluster |
| Morgan's Library Link |
| |
| Rnnn |
| ASM Block Remap Slave |
Used by ASM to asynchronously schedules a Rnnn slave process to remap bad blocks from a mirror copy when read errors are detected |
| TBD |
| |
| RPnn |
| Workload Capture |
These are worker processes spawned by calling DBMS_WORKLOAD_REPLAY.PROCESS_CAPTURE.
RPnn processes execute in parallel and each handles a set of assigned files.
The number of worker processes is controlled by the DBMS_WORKLOAD_REPLAY.PROCESS_CAPTURE parallel_level parameter which, by default, is NULL.
Then, the number of worker processes is equal to the value in v$parameter for 'cpu_count.' When parallel_level is set to 1 no worker processes are spawned. |
| Morgan's Library Link |
| |
| RSM0 |
Data Guard Broker Worker
Monitoring for DMON |
Performs monitoring and management tasks related to Data Guard on behalf of DMON.
The process is created when the Data Guard broker configuration is enabled. |
| Morgan's Library Link |
| |
| RSMN |
| Remote Slave Monitoring (RAC) |
Manages the creation of slave processes that perform tasks on behalf of a coordinating process running in another
cluster instance providing communication with their coordinators and peers |
| Morgan's Library Link |
| |
| RVWR |
| Recovery Writer |
Creates flashback logs and writes Flashback Database data from the flashback buffer in the SGA to the flashback logs.
Also performs some tasks for flashback log automatic management |
| Morgan's Library Link |
| |
| SMCO |
| Space Management Coordinator |
Coordinates the execution of various space management tasks, including proactive space allocation and reclamation.
Dynamically spawns Wnnn slave processes to perform the tasks. |
| TBD |
| |
| SMON |
| System Monitor |
Performs multiple maintenance tasks, including the following:
- Creates and manages the temporary tablespace metadata
- Reclaims space used by orphaned temp segments
- Maintains the undo tablespace by on-lining, off-lining, and shrinking undo segments based on undo space usage statistics
- Cleans up the data dictionary when in a transient and inconsistent state
- Maintains the SCN to time mapping table used to support Flashback
In an Oracle RAC database, the SMON process of one instance can perform instance recovery for other instances that have failed. |
| TBD |
| |
| Snnn |
| Shared Server (formerly MTS) |
In the shared server architecture, clients connect to a dispatcher process, which creates a virtual circuit for each connection.
When the client sends data to the server, the dispatcher receives the data into the virtual circuit and places the active circuit on the common queue to be picked
up by an idle shared server. The shared server then reads the data from the virtual circuit and performs the database work necessary to complete the request.
When the shared server must send data to the client, the server writes the data back into the virtual circuit and the dispatcher sends the data to the client.
After the shared server completes the client request, the server releases the virtual circuit back to the dispatcher and is free to handle other clients.
Several initialization parameters relate to shared servers.
The principal parameters are: DISPATCHERS, SHARED_SERVERS, MAX_SHARED_SERVERS, LOCAL_LISTENER, REMOTE_LISTENER. |
| TBD |
| |
| TEMn |
| ASM Disk Test Error Emulation |
I/O errors can be emulated on ASM disk I/O through named events.
The scope can be the process, instance, or cluster. Optionally, a set of AUs can be chosen for error emulation. |
| TBD |
| |
| VBGn |
Volume Background
ASM and O/S volume driver communications |
Handles messages originating from the volume driver in the operating system and sends them to the ASM instance.
Can run as multiple processes, where n is 0-9. |
| TBD |
| |
| VDBG |
| Volume Driver |
Handles requests to lock or unlock an extent for rebalancing, volume resize, disk offline,
add or drop a disk, force and dismount disk group to the Dynamic Volume Manager driver |
| TBD |
| |
| VKRM |
| Virtual Scheduler (Resource Manager) |
Manages CPU scheduling for all managed processes in accordance with an active resource plan |
| Morgan's Library Link |
| |
| VKTM |
| Virtual Timekeeper |
Instance time publisher publishing two time sets.
One is a wall clock time using a seconds interval and a higher resolution time (which is not wall clock time) for interval measurements.
The VKTM timer service centralizes time tracking and offloads multiple timer calls from other clients. |
| TBD |
| |
| VMB0 |
| Volume Membership |
As an I/O capable client maintains cluster membership on behalf of the ASM volume driver. |
| TBD |
| |
| Vnnn |
| ASM Volume I/O Slave |
Responsible for initializing ASM volume contents during the creation process |
| TBD |
| |
| Wnnn |
| Space Management Slave |
Slave processes dynamically spawned by SMCO to perform background space management tasks.
These tasks include pre-allocating space for locally managed tablespaces and SecureFiles segments based on space usage growth
analysis and reclaiming space from dropped segments. At most 10 Wnnn slaves can run on an instance.
The slaves acts as autonomous agents and after task completion, a process automatically picks up another task from the queue or
terminates itself after being idle for an extended time period. |
| TBD |
| |
| XDMG |
| Exadata Automation Storage Manager |
Monitors all configured Exadata cells for state changes, such as a bad disk getting replaced,
and performs the required tasks for such events. Its primary tasks are to watch for inaccessible disks and cells and when they become accessible again,
and to initiate the ASM ONLINE operation. The ONLINE operation is handled by XDWK. |
| TBD |
| |
| XDWK |
| Exadata Automation Manager XDMG Slave |
Started when asynchronous actions such as ONLINE, DROP, and ADD an ASM disk are requested by XDMG.
After a 5 minute period of inactivity, this process will shut itself down. |
| TBD |
| |
| Xnnn |
| ASM Disk Expel Slave |
At the completion of ASM Rebalance expels dropped disks |
| TBD |
| |
| Demo |
| Selected processes from a 4 node 11.1.0.7 RAC cluster running under Solaris 10 |
USERNAME SCHEMANAME OSUSER PROGRAM TYPE SERVICE_NAME
--------- ----------- ------- ----------------------- ----------- ---------------
SYS oracle oracle@usp9003b (ACMS) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (ARC0) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (ARC1) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (ARC2) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (ARC3) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (ASMB) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (CKPT) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (CJQ0) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (DBW0) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (DBW1) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (DBW2) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (DBW3) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (DBW4) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (DBW5) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (DBW6) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (DBRM) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (DIAG) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (DIA0) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (FBDA) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (GTX0) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (LCK0) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (LGWR) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (LMD0) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (LMS0) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (LMS1) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (LMS2) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (LMON) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (MARK) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (MMAN) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (MMNL) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (MMON) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (m001) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (PING) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (PMON) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (PSP0) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (QMNC) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (q000) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (q001) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (q002) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (RCBG) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (RBAL) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (RECO) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (RMS0) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (RSMN) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (SMCO) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (SMON) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (VKTM) BACKGROUND SYS$BACKGROUND
SYS oracle oracle@usp9003b (W000) BACKGROUND SYS$BACKGROUND
XYZCOM OPS oracle oracle@usp9004b (J000) USER ADMIN_HIGH
XYZCOM OPS oracle oracle@usp9004b (J042) USER ADMIN_HIGH
XYZCOM XYZCOM oracle oracle@usp9004b (J043) USER ADMIN_HIGH
XYZCOM OPS oracle oracle@usp9004b (PZ62) USER ADMIN_HIGH
XYZCOM OPS oracle oracle@usp9004b (PZ75) USER ADMIN_HIGH |
