VDBG 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. The background processes consolidate functions that would otherwise be handled by multiple Oracle Database programs running for each user process. Maintains a connection to the Oracle ASM instance for metadata operations. LSP0 is the initial process created upon startup of Data Guard SQL Apply. The V$PROCESS view lists database processes running in these container processes. Source:- http://docs.oracle.com/cd/E16655_01/server.121/e17615/bgprocesses.htm Some of the parameters that names have been changed, for example NSA1 (Redo transport services has been named as TTnn etc) These processes are fatal processes, if any of them is killed, it will result in instance termination. LDDn - Global Enqueue Service Daemon Helper Slave Helps the LMDn processes with various tasks. IPC0: - IPC Service Background Process - Common background server for basic messaging and RDMA primitives based on IPC (Inter-process communication) methods. When a connection becomes active, the connection broker hands off the connection to a compatible pooled server process. LGWR writes the redo log entries sequentially into a redo log file. Common background server for basic messaging and RDMA primitives based on IPC (Inter-process communication) methods. System might be adversely affected. XDWK gets started when asynchronous actions such as ONLINE, DROP, and ADD an Oracle ASM disk are requested by XDMG. Action Ensure that the executable image is in the correct place with the correct protections, and that there is enough memory. Table F-1 describes Oracle Database background processes. The pooled server process performs network communication directly on the client connection and processes requests until the client releases the server. LMDn processes enqueue resources managed under Global Enqueue Service. These background slave processes perform tasks on behalf of a coordinating process running in another cluster instance. Wait, 92? The principal parameters are: DISPATCHERS, SHARED_SERVERS, MAX_SHARED_SERVERS, LOCAL_LISTENER, REMOTE_LISTENER. Atomic Control File to Memory Service Process, Coordinates consistent updates to a control file resource with its SGA counterpart on all instances in an Oracle RAC environment. The process is created when a Data Guard broker configuration is enabled. These slaves are started by setting the corresponding slave enable parameter in the server parameter file. On completion of individual checkpoint requests, CKPT updates data file headers and control files to record most recent checkpoint. (Inter-process communication) methods. SMCO dynamically spawns slave processes (Wnnn) to implement these tasks. Under normal operation on non-Exadata hardware and on Exadata hardware that is not utilizing ASM volumes, these processes will not be started. Writes modified blocks from the database buffer cache to the data files. Database Apply Process Coordinator Process, Obtains transactions from the reader server and passes them to apply servers. The LMFC process will perform actions related to scanning the dead instance's database flash cache and claim flash blocks mastered by the dead instance. FBDA is also responsible for automatically managing the flashback data archive for space, organization (partitioning tablespaces), and retention. Wnnn processes are slave processes dynamically spawned by SMCO to perform space management tasks in the background. See the Long Description for the DBWn process in this table for more information about the BWnn process. VKRM manages the CPU scheduling for all managed Oracle processes. See "THREADED_EXECUTION" for more information about the THREADED_EXECUTION initialization parameter. SMON is resilient to internal and external errors raised during background activities. After the job is complete, the slave processes commit and then execute appropriate triggers and close the session. XDMG monitors all configured Exadata cells for state changes, such as a bad disk getting replaced, and performs the required tasks for such events. RACcrash,hang,shutdownabort.shutdownabort.,CodeAntenna The dictionary is necessary for logical standby databases to interpret the redo of the new primary database. Coordinates Oracle ASM disk scrubbing operations. Like RMON etc. If required, MARK can also be started on demand when disks go offline in the Oracle ASM redundancy disk group. PO is approved as if using online mode Issue can be seen in the following excerpt from the wfstat.sql script output : The background processes perform maintenance tasks required to operate the database and to maximize performance for multiple users. Performs or schedules many manageability tasks. Extracts and masks bind values from workloads like SQL tuning sets and DB Replay capture files. In Oracle 12c there is a total of 19 new background processes meaning that if you are running in an 11gR2 environment you will only have 92. This process performs the resizing of memory components on the instance. In-memory populate and repopulate tasks running on Wnnn slaves are also initiated from foreground processes in response to queries and DMLs that reference in-memory enabled objects. Query V$STREAMS_APPLY_SERVER for information about the apply server background process. Writes flashback data to the flashback logs in the fast recovery area. Onnn slave processes are spawned on demand. The database starts multiple archiver processes as needed to ensure that the archiving of filled online redo logs does not fall behind. Database instances, Logical Standby, Oracle Streams, XStream Outbound servers, Oracle GoldenGate, Monitors idle connections and hands off active connections in Database Resident Connection Pooling, Transfers redo from current online redo logs to remote standby destinations configured for SYNC transport. CSS monitors RDBMS instances which are connected to the Oracle ASM instance and constantly doing I/Os. The PL/SQL code has been fired as a background job. These are the main Oracle background processes, in no particular order, as all of them are equally important: 1.Database Writer Process. A minimum of three MSnn processes work as a group to provide transactions to a LogMiner client, for example, a logical standby database or a database capture. Performs Oracle ASM disk scrubbing verify operation. CTWR tracks changed blocks as redo is generated at a primary database and as redo is applied at a standby database. They receive and perform units of work sent from the query coordinator. Transfers redo from current online redo logs to remote standby destinations configured for SYNC transport. DMON interacts with the local database and the DMON processes of the other databases to perform the requested function. CSnn slave processes are started on execution of the DBMS_RESOURCE_MANAGER.CALIBRATE_IO() procedure. LMSn and LMnn processes maintain a lock database for Global Cache Service (GCS) and buffer cache resources. The SAnn process allocates the rest of SGA in small chunks. ABMR and BMRn terminate after being idle for a long time. Database instances, Logical Standby, XStream Outbound servers, Oracle GoldenGate. These processes receive, process, and send GCS requests, block transfers, and other GCS-related messages. The DBMS_STORAGE_MAP package enables you to control the mapping operations. The LSP1 process is spawned on a logical standby database that is intended to become the new primary database. Wnnn processes are utilized by the IMCO background process for prepopulation of in-memory enabled objects with priority LOW/MEDIUM/HIGH/CRITICAL, and for repopulation of in-memory objects. The LOG_ARCHIVE_MAX_PROCESSES initialization parameter specifies the number of ARCn processes that the database initially invokes. After a 5 minute period of inactivity, this process will shut itself down. Analyzes single SQL statements sent from SQL Performance Analyzer (SPA). Multiple MSnn processes can exists, where n is 0-9 or a-Z. oracle@zdb010108:/tmp$ srvctl start database -d biet8 PRCR-1079 : Failed to start resource ora.biet8.db CRS-5017: The resource action "ora.biet8.db start" encountered the following error: ORA-01617: cannot mount: 2 is not a valid thread number . AQPC is responsible for performing administrative tasks for AQ Master Class Processes including commands like starting, stopping, and other administrative tasks. Performs synchronous tasks on behalf of LMHB. Wnnn processes are utilized by the IMCO background process for prepopulation of in-memory enabled objects with priority LOW/MEDIUM/HIGH/CRITICAL, and for repopulation of in-memory objects. Handles client requests in the shared server architecture, Emulates I/O errors on Oracle ASM disks through named events. After being started, the slave acts as an autonomous agent. These processes exit when the instance is shut down or terminated. CJQ0 starts only as many job queue processes as required by the number of jobs to run and available resources. The ACMS process works with a coordinating caller to ensure that an operation is executed on every instance in Oracle RAC despite failures. When the THREADED_EXECUTION initialization parameter is set to TRUE on Linux and UNIX, the DBW, PMON, PSP, and VKTM background processes run as operating system processes, and the other background processes run as operating system threads. Performs tasks relating to manageability, including active session history sampling and metrics computation. Performs tasks relating to manageability, including active session history sampling and metrics computation. Performs automation tasks requested by XDMG. 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. In an Oracle RAC database, the SMON process of one instance can perform instance recovery for other instances that have failed. ABMR and BMRn terminate after being idle for a long time. Then, the number of worker processes is computed as follows: When parallel_level is 1, no worker processes are spawned. NSSn can run as multiple processes, where n is 1-9 or A. See the Long Description for the DBWn process in this table for more information about the BWnn process. The database starts multiple archiver processes as needed to ensure that the archiving of filled online redo logs does not fall behind. FMON is started by the database whenever the FILE_MAPPING initialization parameter is set to true. CKPT checks every three seconds to see whether the amount of memory exceeds the value of the PGA_AGGREGATE_LIMIT initialization parameter, and if so, takes the action described in "PGA_AGGREGATE_LIMIT". Global Cache/Enqueue Service Heartbeat Monitor, Monitor the heartbeat of several processes. The RMON process is spawned on demand to run the protocol for transitioning an ASM cluster in and out of rolling migration mode. Performs Oracle ASM disk scrubbing verify operation. SCRn acts as a slave process for SCRB and performs the repairing operations. Parallel Query has two components: a foreground process that acts as query coordinator and a set of parallel slaves (Pnnn) that are background processes. If required, MARK can also be started on demand when disks go offline in the Oracle ASM redundancy disk group. Performs manageability tasks for Oracle RAC. ORA-00443 You May The I/O slaves simulate the asynchronous I/O behavior when the underlying platform does not have native support for asynchronous I/O. For XStream Inbound servers, query V$XSTREAM_APPLY_SERVER. The RMON process is spawned on demand to run the protocol for transitioning an ASM cluster in and out of rolling migration mode. Provides transparent support for XA global transactions in an Oracle RAC environment. After it finishes task execution, it automatically picks up another task from the queue. This background process coordinates the execution of various space management tasks, including proactive space allocation and space reclamation. Job slave processes are created or awakened by the job coordinator when it is time for a job to be executed. Manages and monitors a database that is part of a Data Guard broker configuration. The capture process includes 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. DMON runs for every database instance that is managed by the broker. The process exits upon completion of SGA allocation. Manages global enqueue requests and cross-instance broadcasts. Possible processes include LG00-LG99. In an Oracle IOServer (IOS) instance, the ASMB process enables the IOS instance to connect to an Oracle ASM instance in order to access Oracle ASM disk groups. See "THREADED_EXECUTION" for more information about the THREADED_EXECUTION initialization parameter. The shared server then reads the data from the virtual circuit and performs the database work necessary to complete the request. Apply servers can also enqueue a queue. See Also: Oracle Database The RPOP process is responsible for re-creating and repopulating data files from snapshots files. Once released, the server class processes are moved to a free server pool. The IMCO background process can also initiate repopulation of in-memory objects. After a 5 minute period of inactivity, this process will shut itself down. In an Oracle ASM instance, it coordinates rebalance activity for disk groups. Coordinates execution of tasks such as filtering duplicate block media recovery requests and performing flood control. Table F-1 describes Oracle Database background processes. SCVn acts as a slave process for SCRB and performs the verifying operations. GCRn processes are transient slaves that are started and stopped as required by LMHB to perform synchronous or resource intensive tasks. SCCn acts as a slave process for SCRB and performs the checking operations. In particular, they process incoming enqueue request messages and control access to global enqueues. Provides database service run-time load balancing and topology information to clients. They receive and perform units of work sent from the query coordinator. Coordinates database event management and notifications. Look at the V$ tables. They are also helper processes for LMS to handle non-critical work from global cache service. DMON maintains profiles about all database objects in the broker configuration in a binary configuration file. Performs monitoring management tasks related to Data Guard on behalf of DMON. There can be a maximum of eight CR processes per LMS process, with names from CR00 to CR07. Processes fence requests for RDBMS instances which are using Oracle ASM instances. VBGn handles messages originating from the volume driver in the operating system and sends them to the Oracle ASM instance. Virtual Scheduler for Resource Manager Process, Serves as centralized scheduler for Resource Manager activity. Database instances, Oracle ASM instances, Oracle RAC, Monitors an Oracle RAC cluster to manage global resources. The slave can repeat this operation in case additional jobs need to be run. Job slaves gather all the metadata required to run the job from the data dictionary. Offline timer processing and drop of the disk are performed in this slave. 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. Coordinates the application of redo on a physical standby database. There is one slave process per CPU on each node of the database. When you start the Data Guard broker, a DMON process is created. Processes fence requests for RDBMS instances which are using Oracle ASM instances. Maintains a connection to the Oracle ASM instance for metadata operations, Serves file system requests submitted to an Oracle instance. Oracle ASM instances, Oracle ASM Proxy instances, Forwards Oracle ASM requests to perform various volume-related tasks. CLMN periodically performs cleanup of all the following: dead processes, killed sessions, transactions, network connections, idle sessions, detached transactions, and detached network connections that have exceeded their idle timeout. The External Properties column lists the type of instance in which the process runs. EMNC is a master background process that coordinates event management and notification activity in the database, including Streams Event Notifications, Continuous Query Notifications, and Fast Application Notifications. Symptoms Wait event "RMA: IPC0 completion sync" is in Top Timed Events in AWR report on a fresh 12.2 Real Application Cluster environment. The database event management and notification load is distributed among the EMON slave processes. The RPOP process is responsible for re-creating and repopulating data files from snapshots files. You start troubleshooting an ORA-00445 error by examining your alert log and check for trace files in the bdump (background_dump_dest) directory. The JOB_QUEUE_PROCESSES initialization parameter specifies the maximum number of processes that can be created for the execution of jobs. The slave processes start a database session as the owner of the job, execute triggers, and then execute the job. Wnnn processes execute in-memory populate and in-memory repopulate tasks for population or repopulation of in-memory enabled objects. QMNC is the non-sharded queue master process responsible for facilitating various background activities required by AQ: time management of messages, management of nonpersistent queues, cleanup of resources, and so on. Each RSnn process is a slave process for LMSn to handle remastering work. A logical standby database becomes a primary database because of switchover or failover. RECO uses the information in the pending transaction table to finalize the status of in-doubt transactions. The maximum number of Pnnn processes is controlled by the initialization parameter PARALLEL_MAX_SERVERS. This process handles the extraction of redo and coordinates the application of that redo on a physical standby database. In Database Resident Connection Pooling, clients connect to a connection broker process. These dedicated set of slaves will be used to perform Direct NFS I/Os on behalf of database processes. 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. MARK essentially tracks which extents require resynchronization for offline disks. 6.Archiver Process. Background processes asynchronously perform I/O and monitor other Oracle Database processes to provide increased parallelism for better performance and reliability. The number of these processes vary depending on the active database processes. The number of these processes vary depending on the active database processes. Query V$STREAMS_APPLY_SERVER for information about the apply server background process. RPnn are worker processes spawned by calling DBMS_WORKLOAD_REPLAY.PROCESS_CAPTURE(capture_dir,parallel_level). Performs maintenance actions on Oracle ASM disk groups. These processes handle requests for I/Os targeted at storage not locally accessible. NSSn can run as multiple processes, where n is 1-9 or A. Wnnn slave processes perform work on behalf of Space Management and on behalf of the Oracle Database In-Memory option. When the RDBMS instance terminates due to a failure, all the outstanding I/O's from the RDBMS instance should be drained and any new I/O's rejected. Mandatory Background Processes Optional Background Processes Slave Processes SCRB runs in an Oracle ASM instance and coordinates Oracle ASM disk scrubbing operations. LREG notifies the listeners about instances, services, handlers, and endpoint. All transactions automatically resolved by RECO are removed from the pending transaction table. Quick Example: The GLOBAL_TXN_PROCESSES initialization parameter specifies the number of GTXn processes, where n is 0-9 or a-j. Any changes in the data are managed between the instance's DBW processes and RPOP to ensure the latest copy of the data is returned to the user. Data Guard Broker Fast Start Failover Pinger Process, Maintains fast-start failover state between the primary and target standby databases. The DB_WRITER_PROCESSES initialization parameter specifies the number of Database Writer Processes. The number of worker processes is controlled by the parallel_level parameter of DBMS_WORKLOAD_REPLAY.PROCESS_CAPTURE. Its primary tasks are to watch for when inaccessible disks and cells become accessible again, and to initiate the ASM ONLINE operation. Redo log entries are generated in the redo log buffer of the system global area (SGA). New Background Processes that has been introduced from 12c, compared with 11.2.0.2 Database. They are spawned to help the dedicated LMDn processes with various tasks when certain workloads start creating performance bottlenecks. These container processes are created only when the THREADED_EXECUTION initialization parameter is set to TRUE. This process runs in the database instance and is started when the database instance first begins using the Oracle ASM instance. Performs tasks assigned by the coordinator process performing parallel recovery. Optionally, a set of AUs can be chosen for error emulation. ORACLE 12C List of New Background Processes in Oracle 12c But that is not all. LGWR cannot reuse and overwrite an online redo log group until it has been archived. See Also: Oracle Real Application At specific times CKPT starts a checkpoint request by messaging DBWn to begin writing dirty buffers. The Database Writer Process performs multiblock writes when possible to improve efficiency. The process schedules managed processes in accordance with an active resource plan. Any changes in the data are managed between the instance's DBW processes and RPOP to ensure the latest copy of the data is returned to the user. Performs critical tasks such as instance recovery and dead transaction recovery, and maintenance tasks such as temporary space reclamation, data dictionary cleanup, and undo tablespace management. In an Oracle Streams combined capture and apply optimization, the propagation sender sends LCRs directly to the propagation receiver to improve performance. When an apply server commits a completed transaction, this transaction has been applied. MZnn is a dedicated process for a single MMON slave action. There can be 1 to 100 Database Writer Processes. The database event management and notification load is distributed among the EMON slave processes. In an Oracle ASM instance, the ASMB process runs when the ASMCMD cp command runs, or when a database instance first starts if the server parameter file is stored in Oracle ASM. The number of slave processes spawned is based on the CPU_COUNT value. 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. Database instances, Oracle ASM instances, Oracle RAC, Schedules transactions for Data Guard SQL Apply. MARK essentially tracks which extents require resynchronization for offline disks. I/O errors can be emulated on Oracle ASM disk I/O through named events. Performs Oracle ASM post-rebalance activities. Administrators Guide. Using the data dictionary view USER_SCHEDULER_JOBS, you can verify whether your job is really running.