OracleNotes

Author: Biju

  • Oracle Tidbits – July 2016

    “Oracle *daily* TidBits” (#oratidbit) published at https://www.facebook.com/oraclenotes on weekdays in July 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…

    TidBit
    #oratidbit Oracle SQL Connector for Hadoop Distributed File System (Oracle SQL Connector for HDFS) provides read access to HDFS from an Oracle database using external tables.
    #oratidbit Direct upgrade to 12c is possible if your current Oracle Database is release 10.2.0.5, 11.1.0.7, or release 11.2.0.2 or later. You may directly upgrade from release 12.1.0.1 to 12.1.0.2.
    #oratidbit Starting with Oracle Database 12c, non-rolling upgrades for Oracle Real Application Clusters require Oracle Clusterware on the local node to be up and running.
    #oratidbit On Windows systems, Oracle Universal Installer (OUI) sets environment variables such as PATH, ORACLE_BASE, ORACLE_HOME, and ORACLE_SID in the registry during installation. On Linux and UNIX systems, you must manually set these environment variables.
    #oratidbit On Windows systems, Oracle Universal Installer (OUI) creates the ORA_DBA, ORA_OPER, ORA_HOMENAME_DBA, and ORA_HOMENAME_OPER groups, which are used for operating system authentication for Oracle instances. On Linux and UNIX systems, you must create the operating system groups manually.
    #oratidbit On the Windows platform, to upgrade Oracle Clusterware from releases 10.2.0.5 and 11.1.0.7 to release 12.1, you must perform an interim upgrade to 11.2.0.3 for Oracle Clusterware. After upgrading Oracle Clusterware to release 11.2.0.3, you must move the Oracle Cluster Registry (OCR) and voting disk (VDSK) to Oracle ASM.
    #oratidbit Once installed, there is no simple command to change the Oracle cluster name. On windows you must reinstall Oracle Grid Infrastructure. On Linux, the process will require cluster outage and delete all GI resources, then run $GRID_HOME/crs/config/config.sh script.
    #oratidbit The location of the Oracle central inventory on Windows is always %SYSTEM_DRIVE%\Program Files\Oracle\Inventory. When you install Oracle software on the system, OUI creates the directories for the Oracle central inventory and the Oracle Inventory group, ORA_INSTALL.
    ‪#‎oratidbit‬ Transparent Data Encryption (TDE) enables you to encrypt data so that only an authorized recipient can read it. TDE automatically encrypts data when it is written to disk, and then automatically decrypts the data when applications access it.
    #oratidbit Oracle Data Redaction enables you to redact (mask) column data, using full redaction, partial redaction, regular expressions, and random redaction. Data Redaction performs the redaction at runtime.
    ‪#‎oratidbit‬ You cannot create a Data Redaction policy for a multitenant container database (CDB). This is because the objects for which you create Data Redaction policies typically reside in a PDB.
    #oratidbit The objective in tuning an Oracle database should be to reduce the time that users spend in performing an action on the database, or to simply reduce “DB time”. Time model statistics are accessible from the V$SESS_TIME_MODEL and V$SYS_TIME_MODEL views.
    #oratidbit V$SYSMETRIC_SUMMARY shows a summary of system Metric values. The average, maximum value, minimum value, and the value of one standard deviation for the last hour are displayed for each metric item. Snapshots of this view is kept in AWR as DBA_HIST_SYSMETRIC_SUMMARY.
    #oratidbit V$SYSMETRIC_HISTORY displays system metric values available in the database, with 1 hour history. Snapshots of this view is kept in AWR as DBA_HIST_SYSMETRIC_HISTORY.
    #oratidbit In a Container database, the seed PDB is a system-supplied template that the CDB can use to create new PDBs. The seed PDB is named PDB$SEED. You cannot add or modify objects in PDB$SEED.
    #oratidbit The CREATE DATABASE … ENABLE PLUGGABLE DATABASE SQL statement creates a new Container Database. If you do not specify the ENABLE PLUGGABLE DATABASE clause, then the newly created database is a non-CDB and can never contain PDBs.
    #oratidbit If you start a database instance using the server parameter file (spfile) with the ORACLE_BASE environment variable set, then its value is automatically stored in spfile. If you unset the ORACLE_BASE environment variable and start the instance again, then the database uses the value of the Oracle base directory stored in spfile.
    #oratidbit If you have set ORACLE_BASE for the oracle user during installation, then Oracle Universal Installer creates the Oracle Inventory directory one level above the ORACLE_BASE in the path ORACLE_BASE/../oraInventory.
    #oratidbit For job separation, Oracle RDBMS installation lets you have many OS groups – OSDBA and OSOPER are standard groups. Extended group includes OSBACKUPDBA (backups), OSDGDBA (Data Guard), OSKMDBA (Key Management).
    #oratidbit Oracle Grid Infrastructure for a standalone server includes Oracle Restart and Oracle Automatic Storage Management.
    #oratidbit The orainstRoot.sh script must be run if this is the first time you are installing Oracle software on your system. orainstRoot.sh creates the inventory pointer file (/etc/oraInst.loc).

  • Oracle Tidbits – June 2016

    “Oracle *daily* TidBits” (#oratidbit) published at https://www.facebook.com/oraclenotes on weekdays in June 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…

    TidBit
    #oratidbit The Oracle #APEX session state is managed in the database tables within Oracle Application Express. APEX does not use a dedicated database connection. Instead, each request is made through a separate database session, consuming minimal CPU resources.
    #oratidbit Oracle #APEX three-tier architecture has 1) A web browser 2) Oracle HTTP Server (Apache) with mod_plsql or Oracle Application Express Listener 3) An Oracle database containing Oracle Application Express.
    #oratidbit Oracle #APEX two-tier architecture has 1) A web browser 2) An Oracle database containing the embedded PL/SQL gateway and Oracle Application Express. The embedded PL/SQL gateway runs in the Oracle XML DB Protocol Server in the Oracle database and includes the core features of mod_plsql.
    #oratidbit In Oracle #APEX, the area where you develop applications is called a workspace. A workspace is a virtual private database that enables multiple users to work within the same Oracle Application Express installation while keeping their objects, data, and applications private.
    #oratidbit The hostname in the #APEX login URL will depend on the type of setup. 1) name of the system where Oracle Application Express Listener is installed 2) name of the system where Oracle HTTP Server is installed 3) name of the system where Oracle XML DB Protocol Server is installed.
    #oratidbit Configure Oracle DB Smart Flash Cache using parameters DB_FLASH_CACHE_FILE and DB_FLASH_CACHE_SIZE. To configure multiple devices, comma separate each device and each device size in same order.
    #oratidbit Oracle recommends to configure DB Smart Flash Cache on all RAC nodes (or none), and the total size be approximately same on all nodes.
    #oratidbit The In-Memory (IM) column store is a static pool in the SGA. Data in the IM column store does not reside in the traditional row format but instead in a columnar format.
    #oratidbit In-Memory column store can be enabled at a column, table, materialized view, tablespace or partition level. For a partitioned table, you can populate all of the partitions in the IM column store or a subset of the partitions.
    #oratidbit INMEMORY_SIZE sets the size of the IM column store in a database instance. Value for CDB$ROOT determines the total IM size for CDB. Each PDB can set this parameter to limit the IM size for PDB. If this parameter is not specifically set for a PDB, the PDB inherits the CDB value.
    #oratidbit For maximum speed and efficiency, Oracle Big Data Appliance can be connected to Oracle Exadata Database Machine, which can be connected to Oracle Exalytics In-Memory Machine. All connections use Infiniband that enables high speed data transfer.
    #oratidbit Apache Hive is an open-source data warehouse that supports data summarization, ad hoc querying, and data analysis of data stored in HDFS (Hadoop Distributed File System). It uses a SQL-like language called HiveQL.
    #oratidbit Oracle NoSQL (“Not Only SQL”) Database is typically used to store customer profiles and similar data for identifying and analyzing big data.
    #oratidbit Oracle Big Data SQL supports queries against vast amounts of big data stored in multiple data sources, including Apache Hive, HDFS (Hadoop Distributed File System), Oracle NoSQL Database, and Apache HBase. You can view and analyze data from various data stores together, as if it were all stored in an Oracle database.