Tagged: Database oracle

Cloud / Cloud System / Oracle Application

What is cloud computing?

Aspects and definition of the SaaS, PaaS, DaaS, IaaS platforms. What is cloud computing? Possibility of relying on a specialized provider for the management of one or more IT resources that, from that moment on, are provided via the Web through an outsourcing contract. All this, without the company having to bear the costs of purchasing licenses or machines to take advantage of services indispensable to the business. the supplier to maintain all the infrastructure necessary to manage and distribute the services based on the request (on demand) and with a pay per use formula. All with a subscription to...

Oracle Database 12 c

ORACLE 12C M.T.S. model

Until Oracle Database 12c, Oracle processes did not run as threads on UNIX and Linux systems. Every dedicated connection was represented by an operating system process. In systems where high workload was an issue, the only way to reduce CPU and memory usage was to switch from dedicated connections to shared connections using the multithreaded server (MTS) feature. Starting in Oracle Database 12c the multithreaded database model was introduced, enabling database processes to be executed as operating system threads and reducing the number of dedicated process necessary to manage database services. By default, every new 12c instance is created to...

Oracle Database / Oracle VM

ORACLE: OVMM 3.4.2

PART 1 LINK Oracle VM 3-4-2 Oracle VM Manager 3.4.2 supports current and previous Oracle VM Server releases. Part 2 You can use Oracle VM Manager 3.4.2 to manage Oracle VM Server Release 3.4.x, 3.3.x, 3.2.10, or 3.2.11. If Oracle VM environment consists of Oracle VM Manager Release 3.4.2 and one or more instances of Oracle VM Server at a different release, you should review the list of supported and unsupported operations and features, as follows: Supported Operations Oracle VM supports most common operations when using Oracle VM Manager to manage an instance of Oracle VM Server that is at...

Oracle Database

DB_ULTRA_SAFE parameter

DB_ULTRA_SAFE is a new parameter introduced in 11g. It provides an integrated mechanism to offer protection from various possible data corruptions. and provides critical high availability benefits for Oracle Database. Setting DB_ULTRA_SAFE initialization parameter will configure the appropriate data protection block checking level in the database. It will control DB_BLOCK_CHECKING, DB_BLOCK_CHECKSUM, and DB_LOST_WRITE_PROTECT. DB_BLOCK_CHECKING controls whether or not Oracle performs block checking for database blocks. DB_BLOCK_CHECKSUM determines whether DBWn and the direct loader will calculate a checksum and store it in the cache header of every data block when writing it to disk. DB_LOST_WRITE_PROTECT enables or disables lost write detection....

Oracle Database

ORACLE – VM 3.4.2

During Oracle OpenWorld 2016, the company has announced new version (3.4.2) of their virtualization platform Some of the key new features that have been delivered include: Oracle VM Manager support for previous Oracle VM Server releases: – Manage Oracle VM Server for x86 – 3.4.x, 3.3.x or 3.2.10/11 releases. – Manage Oracle VM Server for SPARC – Agent 3.4.x or 3.3.x releases. Support for NVM Express (NVMe) devices: – Discover NVMe devices and present them to Oracle VM Manager – NVMe devices can be used to store virtual machine disks or create storage repositories. Extended SCSI functionality available for virtual...

Oracle Database / Oracle Database 12 c

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...

Oracle Database

Applicate Baseline

Have you ever been in a situation in which some database queries that used to behave well suddenly started performing poorly? More likely than not, you traced the cause back to a change in the execution plan. Further analysis may have revealed that the performance change was due to newly collected optimizer statistics on the tables and indexes referred to in those queries. One of the many method to secure the execution plan is to use a baseline Below we will explain how to set an execution plan with a baseline having already ‘the optimal plan in memory or having...

Oracle Database

What is the Recycle Bin?

The recycle bin is a data dictionary table containing information about dropped objects. Dropped tables and any associated objects such as indexes, constraints, nested tables, and the likes are not removed and still occupy space. Enabling and Disabling the Recycle Bin ALTER SESSION SET recyclebin = OFF; ALTER SYSTEM SET recyclebin = OFF; ALTER SESSION SET recyclebin = ON; ALTER SYSTEM SET recyclebin = ON; An example of recovery: drop table SALARY2016; select object_name,original_name,type,can_undrop as “undo”,can_purge as “PUR”, droptime from dba_recyclebin where original_name like SALARY%’ order by droptime; OBJECT_NAME ORIGINAL_NAME TYPE undo PUR DROPTIME BIN$JZgAyoU+u1DgUxQVCApelQ==$0 SALARY2016 TABLE YES YES 2016-08-04:13:39:27...

Oracle Database

Copy asm datafile to another diskgroup

SQL> select file_name from dba_data_files where tablespace_name=’TEST’; FILE_NAME —————————————————— +DATA/TEST/datafile/test_01.363.837018395 SQL> alter database datafile ‘+DATA/TEST/datafile/test_01.363.837018395’ offline; RMAN> copy datafile ‘+DATA/TEST/datafile/test_01.363.837018395’ to ‘+DATA_2’; RMAN>run { set newname for datafile ‘+DATA/TEST/datafile/test_01.363.837018395’ to ‘+DATA_2/TEST/datafile/test_01.264.837098131’ ; switch datafile all; SQL> recover datafile ‘+DATA_2/TEST/datafile/test_01.264.837098131’; SQL> alter database datafile ‘+DATA_2/TEST/datafile/test_01.264.837098131′ online; SQL> select file_name from dba_data_files where tablespace_name=’TEST’; FILE_NAME —————————– +DATA_2/TEST/datafile/test_01.264.837098131 SQL> alter diskgroup data drop file ‘+DATA/TEST/datafile/test_01.363.837018395’;

Oracle Database

ORA-01555 Snapshot too old

ORA-01555 is caused by Oracle read consistency mechanism. When you run a select all data refer to the same “Instant”, from the first to the last selected row, for the entire duration of the processing and for how many changes are made on the selected tables from other transaction. When read consistency is not more possibile, the error appear. To solve “ORA-01555” you need to set the parameter of undo_retention and stretch retention. The informations of UNDO is stored in Rollback Segments until the commit or rollback, then these segments are available to be overwritten. The automatic management of UNDO...