Oracle Tidbits – April 2017 #oratidbit

Oracle *daily* TidBits” (#oratidbit) published on Facebook, Twitter and Google+ during weekdays in April 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 #orcldb Multiple Instance Redo Apply (MIRA), a #DB12cR2 feature, enables redo apply on all or some standby instances with RAC configuration.
#oratidbit #orcldb Init parameter ARCHIVE_LAG_TARGET forces a log switch after the specified amount of time (minutes) elapses. The typical value is 1800 (30 minutes). Low values can result in frequent log switches, which could degrade performance.
#oratidbit #orcldb Init parameter AWR_SNAPSHOT_TIME_OFFSET specifies an offset for the AWR snapshot start time. AWR snapshots normally start at the top of the hour. On large systems with many databases, this setting can help to avoid CPU spikes at the top of the hour.
#oratidbit #orcldb Init parameter AWR_SNAPSHOT_TIME_OFFSET has a special value 1000000, which is automatic mode, in which the offset is based on the database name.
#oratidbit #orcldb If init parameter CPU_COUNT is set to 0 (its default setting), then Oracle Database continuously monitors the number of CPUs reported by the operating system and uses the current count. If CPU_COUNT is set to a value other than 0, then Oracle Database will use this count rather than the actual number of CPUs, thus disabling dynamic CPU reconfiguration.
#oratidbit #orcldb Use ASMCMD spbackup, spcopy, or spmove commands to back up, copy, or move an Oracle ASM SPFILE.
#oratidbit #orcldb The minimum MEMORY_TARGET for Oracle ASM instance is 1 GB. If you set MEMORY_TARGET lower, then Oracle increases the value for MEMORY_TARGET to 1 GB automatically.
#oratidbit #orcldb You can upgrade Oracle database directly to 12.2 from versions 11.2.0.3 or later, 12.1.0.1 and 12.1.0.2.
#oratidbit #orcldb The COMPATIBLE parameter minimum value for 12cR1 database is 11.0.0 and for 12cR2 database is 11.2.0.
#oratidbit #orcldb To properly convert from an Enterprise Edition database to a Standard Edition database, perform an Export/Import operation. Use the Standard Edition Export utility to export the data.
#oratidbit #orcldb #windows Starting with Oracle Grid Infrastructure 12c Release 2 (12.2), the Oracle Grid Infrastructure software is available as an image file for download and installation. Extract the image software into the Grid home directory, and run the gridSetup.bat script to start the Oracle Grid Infrastructure installation.
#oratidbit #orcldb #windows Starting with Oracle Database 12c Release 2 (12.2), Oracle Database is supported on Resilient File System (ReFS). ReFS uses checksums for file metadata, and an allocate-on-write method to update data which minimizes the risk of corruption.
#oratidbit #orcldb #windows Oracle Database 12.2 is supported on Windows 7, 8, 8.1, 10, Windows Server 2012, 2012 R2. x64 only.
#oratidbit #orcldb DBA_GOLDENGATE_NOT_UNIQUE view displays all tables that have no primary and no non-null unique indexes. New in #DB12cR2
#oratidbit #orcldb #db12cR2 Oracle implicitly returns to the client application the results of SQL statements executed within a stored procedure, bypassing the explicit use REF CURSORs. This feature eliminates the overhead of re-writing the client-side code.
#oratidbit #orcldb Reference partitioning enables the partitioning of two tables that are related to one another by referential constraints. The partitioning key is resolved through an existing parent-child relationship, enforced by enabled and active primary key and foreign key constraints.
#oratidbit #orcldb I/O calibration statistics can be gathered with the PL/SQL DBMS_RESOURCE_MANAGER.CALIBRATE_IO procedure. I/O calibration is a one-time action if the physical hardware does not change.
#oratidbit #orcldb A bigfile tablespace consists of a single data or temporary file which can be up to 128 TB. The use of bigfile tablespaces can significantly reduce the number of data files for your database. Oracle Database supports parallel RMAN backup and restore on single data files.
#oratidbit #orcldb Automatic data optimization (ADO) is a component of Information Lifecycle Management (ILM) that automates the compression and movement of data between different tiers of storage within the database.

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