Oracle Tidbits – September 2017 #oratidbit

Oracle *daily* TidBits” (#oratidbit) published on Facebook, Twitter, and Google+ during weekdays in September 2017. 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 #db12cR2 The V$MANAGED_STANDBY view is deprecated in Oracle Database 12c Release 2 (12.2.0.1). Use the new view V$DATAGUARD_PROCESS.
#oratidbit #db12cR2 Starting in Oracle Database 12c Release 2 (12.2), the Advanced Replication feature of Oracle Database is unsupported. Start using Oracle GoldenGate.
#oratidbit #db12cR2 DBUA in Database 12cR2 has pause and continue functionality: You can stop the upgrade, and continue the upgrade at a later time.
#oratidbit #db12cR2 init parameter DATA_GUARD_SYNC_LATENCY defines the maximum amount of time (in seconds) that the primary database may wait before disconnecting subsequent destinations after at least one synchronous standby has acknowledged receipt of the redo.
#oratidbit #db12cR2 init parameter ENABLED_PDBS_ON_STANDBY specifies a subset of pluggable databases (PDBs) for replication on a physical standby of a multitenant container database (CDB). In prior releases, you had to specify either all PDBs or none.
#oratidbit #db12cR2 Oracle Diagnostic Pack can be used with an Oracle Active Data Guard standby database that is open read-only.
#oratidbit #db12cR2 When a physical standby database is converted into a primary, STANDBY_DB_PRESERVE_STATES init parameter lets you keep any sessions connected to the standby during the switchover/failover.
#oratidbit The Enterprise Manager Command Line Interface (EM CLI) enables to access Enterprise Manager functionality through a command-line interface or scripts. EMCLI operates in standard command mode, interactive mode or script mode.
#oratidbit OEM13c EMCLI client is downloaded from your OMS – https:///em/public_lib_download/emcli/kit/emclikit.jar. To be able to do scripting download emcliadvancedkit.jar.
#oratidbit The Oracle Database Provider for DRDA is a network front-end that enables client programs to connect to Oracle Database using the Distributed Relational Database Architecture (DRDA) protocol.
#oratidbit Starting with #DB12cR2, Oracle Net listener supports multiple redirects with the parameter, ALLOW_MULTIPLE_REDIRECTS_listener_name. It supports seamless migration of a PDB from a local database to Public Cloud.
#oratidbit Starting with #db12cR2, data compression can be set in the sqlnet.ora file using parameters SQLNET.COMPRESSION and SQLNET.COMPRESSION_LEVELS. Setting these parameters in the sqlnet.ora file affects all the connections using the sqlnet.ora file.
#oratidbit The Automatic Diagnostic Repository (ADR) is a systemwide tracing and logging central repository. The repository is a file-based hierarchical data store for depositing diagnostic information, including network tracing and logging information.
#oratidbit #db12cR2 Oracle RAC Reader Nodes facilitate Oracle Flex Cluster architecture by allocating a set of read/write instances running Online Transaction Processing (OLTP) workloads and a set of read-only database instances across Hub Nodes and Leaf Nodes in the cluster. In this architecture, updates to the read-write instances are immediately propagated to the read-only instances on the Leaf Nodes, where they can be used for online reporting or instantaneous queries.
#oratidbit Start and stop Oracle instances with Oracle Enterprise Manager, SQL*Plus, or SRVCTL. OEM and SRVCTL provide options to start and stop all of the instances in an Oracle RAC database with a single step.
#oratidbit If you stop database instances using “crsctl stop crs” or “crsctl stop cluster -all”, databases are stopped with “shutdown abort”.
#oratidbit Oracle database startup looks for initialization parameter file in $ORACLE_HOME/dbs directory. The file names checked are spfile<sid>.ora, spfile.ora, init<sid>.ora, in order.
#oratidbit In #db12cR2 the optimizer uses the UNION-ALL operator to perform the OR expansion. Earlier, CONCATENATION operator was used.
#oratidbit DBMS_STATS.GET_STATS_HISTORY_RETENTION function shows the current optimizer statistics history retention value. DBMS_STATS.GET_STATS_HISTORY_AVAILABILITY function retrieves the oldest time stamp when statistics history is available.

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