Data Guard

How to Implement Fast-Start Failover 11g

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Before enabling fast-start failover in data guard broker, the only required precondition is enabling Flashback Database. But before enabling Flashback Database, you must enable Flash Recovery Area (FRA). The other configurations that are not required but they might make your fast-start failover go smoothly.Set FastStartFailoverTarget on a database which is the target database to be switched […]
Data Guard

How to Failover to a Standby Database Manually and Rebuild Data Guard – By Example

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Since a fast-start failover (automatic failover) could become a false failover when the observer or the standby database cannot connect to the primary database within a specific time, which may cost the database to lose some transactions followed by reinstating or recreating the standby database (the former primary database).Therefore, it could be a bad idea […]
SQL*Plus

How to Set Autocommit ON

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In the default behavior, if session A wants to see session B’s results, he must be waiting for session B to commit his transaction explicitly or an implicit commit is triggered.Implicit commits will happened under normal session terminations:Gracefully exit.To exit a program will notify database to disconnect from this session and then close the program. […]
Flashback

How to Enable Flashback Database

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Flashback Database Flashback Database can rewind an entire database back to a state of point-in-time, just before operation failures which involved whole database. The result is the same as database point-in-time recovery (DBPITR) performed by RMAN, but rather simple to operate. If you want to save a recently truncated table, Flashback Table helps none, but […]
Fast Recovery Area

How to Enable Fast Recovery Area (FRA)

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Fast Recovery Area (FRA) is a very convenient feature for DBA to backup and restore database. It could happen on us to leave FRA option unchecked during database installations. And we may want to enable fast recovery area after the database has been created. Enable Fast Recovery Area There’re 3 statements make your database starting […]
Performance

How to Check Free Memory in SGA Pools

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The dynamic view gv$sga can tell you how much memory he occupied from OS. They won’t change very often. The real available memory of SGA is provided on gv$sgastat, you can check the free memory of every pool like this.SQL> column “Free (MB)” format 9,999.99;SQL> SELECT inst_id, pool, name, bytes/1024/1024 “Free (MB)” FROM gv$sgastat WHERE name=’free […]
Performance

How to Check SGA Components Memory Distribution on Database 9i

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For database 9i, there is no dynamic view gv$sgainfo like 10g and 11g that can represents current memory distribution of every component. Another dynamic view gv$sga_dynamic_components might help, but the information is incomplete.If you have memory issues on database 9i, you could seek gv$sgastat for help, which can provides more detailed information AFTER some processes and combinations. Let’s […]
Tablespace

How to Check Tablespace Usage By SQL

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If someday, you have no GUI tools around, the only tool you got is sqlplus, a text_based tool, everything must be back to basic. How basic? Every routine jobs including monitoring, maintenance and troubleshooting must be composed as statements and scripts one by one. Checking all tablespaces usage is one of the jobs, very routine, […]