“Oracle *daily* TidBits” (#oratidbit) published on Facebook, Twitter, and Google+ during weekdays in October 2018. Hope you find these helpful to learn something new or to remind you of its existence and use.
| #oratidbit #db18c You can convert a conventional disk group (disk group created before Oracle ASM 18c) to an Oracle ASM flex disk group without using the restrictive mount (MOUNTED RESTRICTED) option. |
| #oratidbit #asm Oracle Automatic Storage Management 18c supports Database 18c or older software versions, including Oracle Database 10gR1 (10.1). When using different software versions, the database instance supports Oracle ASM functionality of the earliest release in use. |
| #oratidbit #asm Use ASMCMD command orapwusr to add, drop, or modify an Oracle ASM password file user. Command lspwuser list the users from the local Oracle ASM password file. |
| #oratidbit #asm Use ASMCMD command lsop to list the current operations on a disk group in an Oracle ASM instance. lsop displays information from the V$ASM_OPERATION view. |
| #oratidbit Oracle Database provides a set of mapping v$ views to show a complete mapping of a ASM data file to locate the exact disk on which any block of a file resides. To enable file mapping, set the FILE_MAPPING initialization parameter to TRUE. |
| #oratidbit #OEM13c Oracle Enterprise Manager Cloud Management Pack for Oracle Database helps to set up a Database Cloud and operate the Database as a Service model. |
| #oratidbit #oracleVM Features in OVM Release 3.4: vCPUs per host raised from 900 to 4096; maximum vdisk size on NFS raised from 2 TB to 10 TB and on OCFS2 from 10 TB to 64 TB. Support for Fibre Channel over Ethernet (FCoE) and Unified Extensible Firmware Interface (UEFI). |
| #oratidbit #db18c Private temporary tables are temporary database objects that are dropped at the end of a transaction or session. Private temporary tables are stored in memory and each one is visible only to the session that created it. Must be prefixed with ORA$PTT_. |
| #oratidbit #OracleVM #VMWare Partition alignment on both physical machines and VMFS partitions prevent performance I/O degradation caused by I/O crossing track boundaries. Partition misalignment add latency to workloads due to a single I/O having to cross physical boundaries. |
| #oratidbit #db18c Use the CREATE PRIVATE TEMPORARY TABLE statement to create a private temporary table. The ON COMMIT clause indicates if the data in the table is transaction-specific (ON COMMIT DROP DEFINITION – the default) or session-specific (ON COMMIT PRESERVE DEFINITION). |
| #oratidbit #db18c The SLEEP procedure that belonged to DBMS_LOCK in earlier releases is now in package DBMS_SESSION. For backward compatibility, DBMS_LOCK.SLEEP is still available, but not documented. |
| #oratidbit #db18c Names of private temporary tables must be prefixed according to the initialization parameter private_temp_table_prefix. Default is ORA$PTT_. Value must begin with ORA$. After setting the prefix, regular table, view, and object names cannot use the same prefix. |
| #oratidbit A SQL patch is a patch that contains SQL scripts which need to be run after OPatch completes. DBA_REGISTRY_SQLPATCH contains information about the SQL patches that have been installed in the database. DBA_REGISTRY_SQLPATCH is updated by the datapatch utility. |
| #oratidbit #oracleTFA The Trace Filey Analyzer recommended install on Linux is as root daemon mode to get the richest capabilities. Recommended install location is /opt/oracle.tfa. |
| #oratidbit #oracleTFA Use “tfactl summary” for a quick real-time view of all key database components using the Trace File Analyzer. It shows any potential problems with important elements (database, clusterware, ASM, patch, listener, OS, network). |
| #oratidbit #oracleTFA Use the “tfactl changes” command to view the changes detected by Oracle Trace File Analyzer. Report any noted changes in the system setup over a given time period. This includes database a parameters, OS parameters, patches applied. |
| #oratidbit #oracleTFA The Oracle Trace File Analyzer install includes a Web Application Resource (WAR) file (TFA_HOME/jlib/tfa.war) to enable the REST service via Apache Tomcat. |
| #oratidbit #oracleTFA Oracle Trace File Analyzer root installations on Linux or Solaris will automatically setup and run the ORAchk daemon. The daemon will be restarted at 1am every morning, in order to discover any environment changes. |
| #oratidbit #dbupgrade Make all tablespaces OFFLINE NORMAL or make READ ONLY except for SYSTEM, SYSAUX, <UNDO> prior to upgrade. If upgrade fails, only the SYSTEM and rollback datafiles need to be restored rather than the entire database. |
| #oratidbit #dbupgrade Database Upgrade Assistant (DBUA) has an option to use flashback database feature for restoring and recovering the Database in case of upgrade failure. This can be done by selecting the option “Use Flashback and Guaranteed Restore Point”. |
| #oratidbit #Multitenant You can create up to 252 PDBs with Oracle Enterprise Edition (on-prem). On Oracle Engineered Systems (EE-ES) and Oracle Cloud (DBCS & ExaCS), you can create up to 4096 PDBs. |
| #oratidbit #Sharding No limit on the number of either primary shards or standby shards if every shard has an Oracle Active Data Guard, Golden Gate, or Oracle RAC license. Without license, use is limited to three primary shards, with basic Data Guard standbys. |
| #oratidbit #oraclecloud Exadata Cloud Service Bare Metal can scale up to 336 cores and 8 nodes, with high memory and storage capacity (over 1 petabyte) and unlimited I/Os. Exadata Cloud Machines include Oracle Database Enterprise Edition Extreme Performance. |