This article will be discussing a new feature of Oracle 12c Database, Oracle Multitenant Architecture, which enables an Oracle Database to act as multitenant Container Database (CDB). A CDB includes one or many pluggable databases (PDBs). One default PDB, the seed PDB, is provided by Oracle in every CDB. Users cannot make changes to the seed PDB, but user can create additional PDBs using this default PDB. A CDB can contain 253 PDBs.
Oracle Corporation has released Database 12c for general availability this month. We’re busy geeking out on the new features like multi-tenancy, heat maps, etc. We’ll be back next month with blog posts about some new 12c features.
The PL/SQL function result cache provides the mechanism for caching the results of PL/SQL functions in a shared global area (SGA), available to every session that runs on your database.
When a result-cached function is invoked, the system checks the cache. If the cache contains the result from a previous call to the function with the same parameter values, the system returns the cached result to the invoker and does not re-execute the function body.
SQL Access Advisor allows DBAs and developers to analyze individual SQL statements, SQL tuning sets or the entire system and recommend materialize views, partitioning and indexes on tables. There are two interfaces of SQL Access Advisor: Oracle Enterprise Manager and DBMS_ADVISOR package. The Oracle Enterprise Manager interface is easy and user-friendly, but DBMS_ADVISOR package provides the same recommendations from SQL*Plus, which is useful in environments that do not have OEM installed. SQL Access Advisor is a part of the Oracle Tuning Pack, which also requires the Diagnostic Pack.
A customer had an interesting problem recently involving selective bit-flipping. The real scenario was a bit more complicated, but it came down to the following scenario: the client has a large number of members. Each member visits multiple times. They want to switch the value between X2 and NULL every time a ‘true’ event occurs.