Linux

How to Remove No-Name or Empty-Name Files

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After you finish your shell scripting, you’d like to try your scripts to see the result in your test environment. In the debug phase, you will generate a lot of echo message to see where’s problems, and maybe you will get some unrecognized files, like this: $ ls -il total 5     709233 -rw-r–r– […]
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 have noticed 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 […]
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 […]