• Oracle

    Oracle RMAN Recovery manager-13

    RMAN- Recovery manager It’s a utility and an oracle internal tool. Keyword — rman Features of RMAN RMAN only backup the used block, incremental backup with block change tracking and optimization on archivelog. Whereas hot & cold backup.  Less space used. From 10g onwards, You can backup used +free data by rman. It’s called image copy. Used data backup is called backupset backup. Default one. All data backup — Image copy Used backup–Backupset By default, We can compress the currently not used & unused block compression to skip datafile blocks RMAN also supports binary compression of backup sets. The supported algorithms are BZIP2 (default) – max compression and ZLIB –…

  • Oracle

    Oracle Export and Import Backup and Restore-12

    Export and Import Backup and Restore Logical backup: Normal export/import and Data pump Data pump has many features. Like (PARALLEL, Job,NETWORK_LINK,REMAP DATAFILE & tablespace, exclude, include, version, extimate_only) It mostly done in the DB server itself. It access data by direct path and external tables a master process, and worker processes. Whereas normal export/import uses Conventional path. DataPump: Faster, Filtering option (remaps, compression & parallel), job, & self-tuning etc Data Pump Export/Import Normal Export/Import Filtering of data and metadata and remaps etc Not much Change PARTITION_OPTIONS while import No Two process at DB server level Master & Worker It runs on DB & client level Data Pump jobs runs server,…

  • Oracle

    Oracle Backup and Recovery-11

    Backup and Recovery   Types: Physical backup – i. Cold backup ii. Hot backup & RMAN Logical backup – i. Export ii. Import Cold Backup Hot Backup RMAN Offline / consistent backup Online  / partial / inconsistent backup,  only a read consistent and no active transactions backup consistent DB down Can Backup online. Can Backup online. Both modes Database should be in archive mode Any Mode All physical files Tablespace, control file All physical + logical   Cold Backup: It’s an offline backup/ consistent backup. Database needs to be down by – Shutdown immediate /normal Oracle will run checkpoint and write a SCN number. If you use, shutdown abort for…

  • Oracle

    Oracle Indexes and Constraints-10

    Indexes: http://docs.oracle.com/cd/E11882_01/server.112/e40540/indexiot.htm#CNCPT1895 http://www.oracle.com/us/education/my-richardfoote-seminar-079059.html A table dependent object. (Root — Branch –Leaf) An index is an optional structure, associated with a table or table cluster. Index properties: Usability Indexes are usable (default) or unusable. An unusable index is not maintained by DML operations and is ignored by the optimizer. An unusable index can improve the performance of bulk loads. Instead of dropping an index and later re-creating it, you can make the index unusable and then rebuild it. Unusable indexes and index partitions do not consume space. When you make a usable index unusable, the database drops its index segment. When we move the table without index it will be unusable.…