Oracle 12c

ORACLE 12C: Dataguard Far Sync

Oracle Dataguard Far Sync instance is a new feature introduced in Oracle Database 12c, which simply works like a archive/redo repeater.. Far sync instance is something different than the Oracle Database instance, as its mission is accepting redo from the primary database and then shipping that redo to other members of the Oracle Data Guard configuration.. Far Sync instance is an instance without a database.. Although; it has controlfile, and capability to read from standby redolog files and write them into its local archive log files, Far Sync instance does not map any database file, in other words, does not Read More

ORACLE 12 rel.2 – Partitioning new features

In Oracle 12c rel.2 a great number of enhancements to the Oracle database Partitioning option have been introduced. These include: Automatic List Partitioning Filtered Partition maintenance operations Multi-Column List Partitioning Online conversion of non-partitioned to partitioned table Read-only Partitions Partitioned External Tables Automatic List Partitioning: The ability to partition a table based on distinct values in a column has been around since quite some time, but what is new in Oracle database 12.2 is that we can initially partition the table based on values that are known and present in the column we would like to partition the table on. Read More

Oracle 12c release 2: new features

Oracle introduced the long awaited Database 12c Release 2 earlier this year at OracleOpen World. Oracle just released Oracle Database 12c Release 2 for on-premises Linux and Solaris. Find below an incomplete list of the main new features: 1. Multi-Instance Redo Apply : With Oracle 12c Release 2, you can apply redo logs to multiple instance at the same time to improve recovery time objective. 2. Oracle Database Sharding : With Oracle 12c Release 2, you can horizontally partitioned data across many databases and present them as a single logical database to application. 3. Creating Data Guard Standbys With Database Creation Assistant : You Read More

Oracle12C : Database Firewall

The Oracle Database Firewall enables organizations to protect their databases from internal and external attacks. Oracle Database Firewall allows unauthorised SQL traffic on the network to be monitored and blocked before reaching the database. Database Firewall for Security and Compliance Oracle Database Firewall monitors and enforces normal application behavior in order to avoid the increasingly sophisticated Data Centre attacks that can lead to unauthorised external access. The security control of Oracle Database Firewall helps to prevent malicious activity such as SQL injection and application bypass from reaching the database. Next-Generation Network-based Database Security The grammar of the SQL statements being Read More

ORACLE 12C : Extended Data Type

With the previous Oracle database release, long characters strings of more then 4000 bytes had to be handled using CLOB or LONG data types. Starting from Oracle 12c was introduced a new system parameter: MAX_STRING_SIZE. This parameter allows string data types to be much larger when the parameter is changed from its default value STANDARD to EXTENDED. New higher limits (in bytes) are available for following types: – VARCHAR2 – 32767 bytes – NVARCHAR – 32767 bytes – RAW – 32767 bytes To use extended version you need to set new initialization parameter MAX_STRING_SIZE and run sql script utl32k.sql. Set Read More

ORACLE 12C : approx_count_distinct parameter

The APPROX_COUNT_DISTINCT function was added, but not documented, in Oracle 11g to improve the speed of calculating the number of distinct values when gathering statistics using the DBMS_STATS package. Oracle database 12c ( now includes the function in the documentation, so we are free to use it in our applications as a supported SQL function. It returns approximate number of rows that contain distinct values of expression. It’s alternative to the COUNT (DISTINCT expr) function, which returns the exact number of rows that contain distinct values of expr. For processing large amounts of data it’s significantly faster than COUNT, with Read More