Tag: oratidbit

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Oracle Tidbits – December 2016 #oratidbit

“Oracle *daily* TidBits” (#oratidbit) published on Facebook, Twitter and Google+ during weekdays in December 2016. You will also see these tidbits, one tidbit at a time, for each page refresh on the right side of this blog as well… Hope you find these helpful to learn something new or to remind you of its existence and use.

OraTidBit
#oratidbit #DB12cR2 You can capture Automatic Workload Repository (AWR) data for Oracle Active Data Guard standby databases. This feature enables performance tuning of Oracle Active Data Guard standby databases.
#oratidbit #DB12cR2 INACTIVE_ACCOUNT_TIME initialization parameter automatically locks the database user account who has not logged in to the database instance in a specified number of days.
#oratidbit #db12cR2 You can prioritize the PDBs in a CDB when you upgrade the CDB. The PDBs with higher priority are upgraded before PDBs with lower priority.
#oratidbit #db12cR2 A CDB can run in local undo mode or shared undo mode. Local undo mode means that every container in the CDB uses local undo. Shared undo mode means that there is one active undo tablespace for a single-instance CDB.
#oratidbit #db12cR2 In 12.2, tables with BFILE columns can be redefined online.
#oratidbit #db12cR2 In 12.2, Query the V$ONLINE_REDEF view to monitor the progress of an online table redefinition operation.
#oratidbit #db12cR2 In 12.2, SYSRAC is a new administrative privilege for tasks related to Oracle Real Application Clusters (#Oracle #RAC) operations.
#oratidbit #DB12cR2 ALLOW_GROUP_ACCESS_TO_SGA is new parameter and controls group access to shared memory on UNIX platforms. The default value is false, which means that database shared memory is created with owner access only. In Oracle Database releases prior to Oracle Database 12c Release 2 (12.2.0.1), database shared memory was created with owner and group access.
#oratidbit #DB12cR2 AWR_PDB_AUTOFLUSH_ENABLED is new parameter and enables you to specify whether to enable or disable automatic Automatic Workload Repository (AWR) snapshots for all the PDBs in a CDB or for individual PDBs in a CDB.The default value of AWR_PDB_AUTOFLUSH_ENABLED is false. Thus, by default, automatic AWR snapshots are disabled for all the PDBs in a CDB. When you change the value of AWR_PDB_AUTOFLUSH_ENABLED in the CDB root, the new value takes effect in all the PDBs in the CDB. Therefore, if you change the value of AWR_PDB_AUTOFLUSH_ENABLED in the CDB root to true, the value of AWR_PDB_AUTOFLUSH_ENABLED is also changed to true in all of the PDBs, so that automatic AWR snapshots are enabled for all the PDBs. You can also change the value of AWR_PDB_AUTOFLUSH_ENABLED in any of the individual PDBs in a CDB, and the value that is set for each individual PDB will be honored. This enables you to enable or disable automatic AWR snapshots for individual PDBs.
#oratidbit #DB12cR2 ENABLE_AUTOMATIC_MAINTENANCE_PDB is new parameter and can be used to enable or disable the running of automated maintenance tasks for all the PDBs in a CDB or for individual PDBs in a CDB. When you change the value of ENABLE_AUTOMATIC_MAINTENANCE_PDB in the CDB root, the new value takes effect in the root and in all the PDBs in the CDB. You can also change the value of ENABLE_AUTOMATIC_MAINTENANCE_PDB in any of the individual PDBs in a CDB, and the value that is set for each individual PDB will be honored. This enables you to enable or disable automated maintenance tasks for individual PDBs.
#oratidbit #DB12cR2 ENABLED_PDBS_ON_STANDBY is new parameter and specifies which pluggable databases (PDBs) to replicate on an Oracle Data Guard standby database. The asterisk (*) and question mark (?) wildcard characters are supported.
#oratidbit #DB12cR2 REMOTE_RECOVERY_FILE_DEST is new parameter and specifies a directory from which to read archive log files during a pluggable database (PDB) refresh operation if the source is not available.
#oratidbit #DB12cR2 UNIFORM_LOG_TIMESTAMP_FORMAT is new parameter and specifies that a uniform timestamp format be used in Oracle Database trace (.trc) files. When the value of UNIFORM_LOG_TIMESTAMP_FORMAT is TRUE, the format used for timestamps in trace files is standardized on universal time with millisecond precision. When the value of UNIFORM_LOG_TIMESTAMP_FORMAT is FALSE, trace files include a mix of timestamps using different precisions, with some timestamps showing local time and other timestamps showing universal time.
#oratidbit Before you create a DBaaS instance on Oracle Database #Cloud (#DBaaS), you must setup an SSH public/private key pair to connect to compute node and optionally Oracle storage cloud service container to backup the database to cloud.
#oratidbit Use dbaascli utility on Oracle #DBaaS cloud deployments to perform a variety of life-cycle and administration operations including patching, database recovery and data guard switchover.
#oratidbit Use raccli utility #DBaaS cloud deployments that use Oracle Real Application Clusters (RAC) to perform a variety of life-cycle and administration operations including backup, recovery, patching, security configurations and so on.
#oratidbit Use dbpatchmdg utility #DBaaS cloud deployments that are configured with Oracle Data Guard to perform a variety of patching operations.
#oratidbit Use the oracle-dbcs-cli utility on your Linux computer to connect to Oracle Cloud and perform a variety of life-cycle and administration operations on Oracle Database Cloud Service deployments (non RAC).
#oratidbit To use #Oracle Database Backup Cloud Service you’ll subscribe to the service, install the Oracle Database Cloud Backup Module, and configure your environment to send backups to the cloud using familiar RMAN commands.
#oratidbit Oracle Database Exadata Express Cloud Service delivers a managed Oracle Database 12c Release 2 Enterprise Edition with options, running on Oracle Exadata engineered systems.
#oratidbit #DB12cR2 In 12.2, the maximum length for most database object names has increased from 30 bytes to 128 bytes.
#oratidbit #DB12cR2 In 12.2, you can encrypt undo tablespaces, temporary tablespaces, and the SYSTEM and SYSAUX tablespaces. Also, encrypt both offline and online tablespaces.
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Oracle Tidbits – May 2016

“Oracle *daily* TidBits” (#oratidbit) published at https://www.facebook.com/oraclenotes on weekdays in May 2016. You will also see these tidbits, one tidbit at a time, for each page refresh on the right side of this blog as well… Hope you find these helpful to learn something new or to remind you of its existence and use…

#oratidbit 101: In a CDB, the UNDO_MANAGEMENT parameter must be AUTO. There is one active undo tablespace for a single-instance CDB. Cannot have separate UNDO tablespace for PDBs.
#oratidbit To create a service for a PDB using the SRVCTL utility, use the add service command and specify the PDB in the -pdb parameter. If you do not specify a PDB in the -pdb parameter when you create a service, then the service is associated with the root.
#oratidbit PDB management with Oracle EM Express is available starting with Oracle Database 12c Release 1 (12.1.0.2).
#oratidbit There is a default temporary tablespace for the entire CDB. You optionally can create additional temporary tablespaces for use by individual PDBs.
#oratidbit Specify STORAGE clause in CREATE PLUGGABLE DATABASE to specify the amount of storage that can be used by all tablespaces that belong to the PDB. Default is UNLIMITED.
#oratidbit Cluster Verification Utility (CVU) is a command-line tool that you can use for preinstallation and postinstallation checks of your cluster environment. OUI runs CVU after the Oracle Clusterware installation to verify the environment.
#oratidbit Oracle Cluster Registry (OCR) maintains cluster configuration information and configuration information about any cluster database within the cluster. The OCR contains information such as which database instances run on which nodes and which services run on which databases.
#oratidbit For a fixed-size undo tablespace, Oracle Database automatically tunes the system to give the undo tablespace the best possible undo retention. For an automatically extensible undo tablespace, Oracle Database retains undo data longer than the longest query duration and the low threshold of undo retention specified by the UNDO_RETENTION parameter.
#oratidbit Query V$UNDOSTAT.TUNED_UNDORETENTION to determine the amount of time for which undo is retained for the current undo tablespace.
#oratidbit To use Oracle Flashback Transaction Query feature, supplemental logging must be enabled in the database – ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;
#oratidbit When upgrading your database, DBUA expects that both the source (pre-12c) Oracle home and the destination (new 12c) Oracle home are owned by the same user.
#oratidbit Starting with Oracle Database 12c, Oracle XML DB is a mandatory component of Oracle Database. You cannot uninstall Oracle XML DB, and there is no option to exclude it when you create an Oracle database.
#oratidbit Starting with Oracle Database 11g Release 2 (11.2), setting JOB_QUEUE_PROCESSES to 0 causes both DBMS_SCHEDULER and DBMS_JOB jobs to not run.
#oratidbit A Global Data Services (GDS) configuration and its global services are created and managed using the GDSCTL command-line interface. GDS is a highly effective solution for automatic workload management across a set of replicated databases.
#oratidbit Oracle NoSQL Database is available in Community Edition (CE) and Enterprise Edition (EE). Only EE has integration with Oracle Stack such as Oracle Database External Table Integration, Oracle Big Data SQL integration, and so on.
#oratidbit You can model data in Oracle NoSQL Database by using Tables, JSON schemas or a raw key-value interface. Tables are the easiest way to model data and they provide the highest level of abstraction.
#oratidbit Setting database initialization parameter STATISTICS_LEVEL to BASIC disables many Oracle Database features, including ADDM. Setting parameter CONTROL_MANAGEMENT_PACK_ACCESS to NONE also disables ADDM.
#oratidbit ADDM analysis of I/O performance partially depends on DBIO_EXPECTED, which is the average time it takes to read a single database block in microseconds – default is 10 milliseconds.