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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.
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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.