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How to know the size of oracle database?

Oracle database consist of datafiles,redo log files, control files and temp files. And sum of all these file is the size of the oracle database. i.e   select ( select sum(bytes)/1024/1024/1024 data_size from dba_data_files ) + ( select nvl(sum(bytes),0)/1024/1024/1024 temp_size from dba_temp_files ) + ( select sum(bytes)/1024/1024/1024 redo_size from sys.v_$log ) + ( select sum(BLOCK_SIZE*FILE_SIZE_BLKS)/1024/1024/1024 … continue reading

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ORA-01033 : file 1 needs media recovery

Possbile Solutions: Basically your system.dbf is corrupted / incomplete.. needs recovery1. kill all connects from OS level2. ps -ef |grep pmonans kill the database service that is running…3. Do you have any RMAN backup or archivelogs?If YES – Recover database with the archivelogsif NO – try to recover using all the redo logs..Commnad: recover database … continue reading

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what is consistency =y in export ?

It makes all of the queries run by exp be “as of the same point in time– consistent with regards to eachother”Imagine if you started an export at 9am of the EMP and DEPT tables.EMP started exporting at 9am and DEPT at 9:15am.Now, the EMP data would be “as of 9am”, but the DEPT data … continue reading

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why we use crosscheck, obsolete , restore validate in rman?

1. why we use crosscheck command in rman ? 2. why we use obsolete command in rman ? 3. why we go for restore database validate ? Solution : .1. To check whether backups are physically available2. To check whether backups are valid (redundant)3. To check the existing backup pieces are valid to restore  

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What is meant by incremental,cumulative and complete backups?

Full BackupsA full backup is different from a whole database backup. A full data file backup is a backup that includes every used data block in the file. RMAN copies all blocks into the backup set or image copy, skipping only data file blocks that have never been used. For a full image copy, the … continue reading

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how to find current size, available size, used size and total size in a Tablespace .

For used size: select sum(bytes) from dba_segments where tablespace_name=”; For available size: select sum(bytes) from dba_datafiles where tablespace_name=”; select df.tablespace_name “Tablespace”, totalusedspace “Used MB”, (df.totalspace – tu.totalusedspace) “Free MB”, df.totalspace “Total MB”, round(100 * ( (df.totalspace – tu.totalusedspace)/ df.totalspace)) “Pct. Free” from (select tablespace_name, round(sum(bytes) / 1048576) TotalSpace from dba_data_files where tablespace_name like ‘%xxxxxxxxxxxxxx%’ group … continue reading

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Why expdp is faster than regular exp?

Solutions: 1. expdp is faster due to parallelism. 2. expdp is more advanced. 3. expdp is direct path export which is Oracle Data block. Exp uses SQL level extraction. 4. Exp,imp runs on client side, but expdp and impdp runs on server side.so we have much control compared to traditional exp,imp !  

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How to know log sequence number/SCN of Archive log file for restoration purpose

Possible Solutions: select * from v$log; select sequence# from v$archived_log; RMAN>RESTORE DATABASE PREVIEW  

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The flashback recovery area has run out of space …under different scenarios

The flashback recovery area has run out of space what different solution to overcome that issue. as we see some expert solution to this question lets add some scenarios on that,now i know how i increase-up the FRA say db_recovery_file_dest_size = 10G what happened when we reduced it to db_recovery_file_dest_size = 5G……? The flash recovery … continue reading

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What is the difference between ‘archived’ and ‘applied’ on v$archived_log view ?

Archived means whether the archive is generated or not on primary and  applied means whether the archive applied on standby or not. Enjoy.  

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