Unix

How to Monitor Unix Memory Usage by Processes

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In Unix, you have many tools to monitor the overall memory usage, such as “vmstat“, “sar“, “top” and “free“.“vmstat“, you can monitor the field “free” to see how much memory left now, for example:$ vmstat 2 5 procs     memory            page            disk          faults      cpu r b w   swap  free  re  mf pi po fr de sr m1 m1 […]
User and Schema

What is the Difference Between SYSDBA and SYSOPER Privileges

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SYSDBA and SYSOPER According to Oracle documentation about administrative accounts and privileges, I compared their privileges between SYSDBA and SYSOPER as below: Allowed Actions SYSDBA SYSOPER Perform STARTUP and SHUTDOWN operations ALTER DATABASE: open, mount, back up, or change character set Only open, mount and back up CREATE DATABASE DROP DATABASE CREATE SPFILE ALTER DATABASE […]
User and Schema

Who has SYSDBA privilege?

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SYSDBA is a system privilege. By default, only SYS has the privilege, but it can be changed by granting to other user. Although it’s a system privilege, and very special, you will hardly find any other user has SYSDBA privilege by looking up dictionary view, so we also call it administrative privilege. Similarly, SYSOPER is […]
PFILE and SPFILE

How to Resolve SPFILE Does Not Work

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You might notice that the newly created SPFILE for a RAC database was not taking effective after restarts. I think you might create the SPFILE in the wrong places.Oracle 11g RAC stores all the shared files in ASM, including control files, spfile, data files. Thus, it starts all the instances with the shared SPFILE. If […]
Listener

How to Remotely Connect a NOMOUNT Database

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Users who belong to OSDBA or OSOPER can access a database in any states on local host if OS authentication is ON in the listener. It’s probably not a problem on local, but remote or external access would be an issue to connect to the database. Normally, you cannot connect to a nomount state database […]
RMAN

How to Pass Date Format into RMAN

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After you set RMAN log location (2 Ways to Set RMAN Log Location), the next problem you will meet is the format of timestamp in the log, which could be too coarse to judge the actual time like this:08-OCT-12If you are using sqlplus, you can alter the session and set NLS_DATE_FORMAT to modify the format, […]
RMAN

2 Ways to Set RMAN Log Location

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RMAN is a client side utility like sqlplus used to interoperate with DB, we usually compose a script file or a batch file to run via cron job or schedule. If any problems result from RMAN, you can check the log file to debug.There is no RMAN default log location in PFILE to set, so you […]
RMAN

When RMAN met Resource Manager

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Users notified DBA that they found AP responded longer than normal starting from 22:00 everyday, especially when a period of running RMAN on the host, we checked STATPACK report to search the root cause, RMAN was running fine, but there was a wait event utilizing too much resources, see the report summarized below:…Top 5 Timed […]