Oracle Tidbits – December 2017 #oratidbit

Oracle *daily* TidBits” (#oratidbit) published on Facebook, Twitter, and Google+ during weekdays in December 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 Credentials created using the DBMS_CREDENTIAL.CREATE_CREDENTIAL procedure are database objects that hold a username/password pair for authenticating and impersonating EXTPROC callout functions, remote jobs, external jobs and file watchers from the SCHEDULER.
#oratidbit #orcldb Oracle Advanced Queuing stores user messages in abstract storage units called queues. When business applications communicate with each other, producer applications enqueue messages and consumer applications dequeue messages.
#oratidbit #orcldb XStream consists of Oracle Database components and application programming interfaces (APIs) that enable client applications to receive data changes from an Oracle database and send data changes to an Oracle database.
#oratidbit #db12cR2 Init parameter ASM_IO_PROCESSES in 12.2 specifies the number of I/O worker processes to be started in an Oracle Automatic Storage Management (Oracle ASM) IOServer instance.
#oratidbit #db12cR2 Init parameter ENABLE_AUTOMATIC_MAINTENANCE_PDB in 12.2 can be used to enable or disable the running of automated maintenance tasks for all the PDBs in a CDB or for individual PDBs in a CDB.
#oratidbit #db12cR2 In 12.2 Oracle Multitenant license allows 252 PDBs in Enterprise Edition and 4096 PDBs in EE on Exadata.
#oratidbit #db12cR2 When the character set of the CDB root is AL32UTF8, any container in the CDB canSharding is a data tier architecture in which data is horizontally partitioned across independent databases. use a character set that is different from the CDB root and different from other containers in the CDB.
#oratidbit A proxy PDB provides access to another PDB in a remote CDB. Use the CREATE PLUGGABLE DATABASE statement to create a proxy PDB by referencing the other PDB. Use a proxy PDB when you want a local context for a remote PDB.
#oratidbit #db12cR2 Use FLASHBACK PLUGGABLE DATABASE command to rewind a PDB to any SCN without affecting other PDBs in a CDB. You can also create a restore point specific for a PDB, and rewind the PDB to this restore point without affecting other PDBs.
#oratidbit #orcldb database acquires a full table lock on the child table when no index exists on the foreign key column of the child table, and a session modifies a primary key in the parent table.
#oratidbit #Sharding is a data tier architecture in which data is horizontally partitioned across independent databases. Sharding provides linear scalability and complete fault isolation for the most demanding OLTP applications.
#oratidbit In Oracle Database 12c Release 1 (12.2.0.1) all shards and shard catalog must be non-CDB databases.
#oratidbit #db12cR2 Use the new -R option for the parallel upgrade utility (catctl.pl) to resume the upgrade at the point of failure, so that only the missing upgrade phases are rerun – Automatic Resume After Failed Upgrades feature.
#oratidbit #db12cR2 Use the new -T option for the parallel upgrade utility (catctl.pl) to set user tablespaces automatically to READ-ONLY during an upgrade. After the upgrade, the tablespaces are changed back automatically to READ/WRITE.

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