While shutting down the oracle database , i have encountered the ora-00600 error. I checked “ps -ef | grep ora_” and found no oracle process are running. I got confused ..
SQL> shutdown immediate
Database closed.
Database dismounted.
ORA-00600: internal error code, arguments: [LibraryCacheNotEmptyOnClose], [], [], [], [], [], [], []
And i serached in web for the error and i found that Continue Reading»
Execess redolog generation during hot backup
What happens during tablespace begin backup?
When a tablespace is in backup mode, datafile’s header belonging to the tablespace will be freezed rather than the datafile.So checkpoint happens and update the datafile header with checkpoint SCN and there after it is freezed until we take tablespace out of backup mode.
Since header only freezed,datafile remains as normal and data changes happens continuously to this datafile while in backup mode. So the datafile which coping during backup is inconsistent. That’s reason of execess redolog generation.
There are many ways to troubleshoot the performance Issues in oracle database. Here you can find some methods to troubleshoot performance Issues.
Scenario 1:
Users are complaining that Application is slow.
DBMS_CRYPTO package provides an interface to encrypt and decrypt stored data. For example, the table CUST_MASTER has three columns ACNO,NAME,BALANCE and you wish to encrypt the column NAME and BALANCE. Using the dbms_crypto.ENCRYPT functions,you can create your function to encrypt data.
Example:
Create a table CUST_MASTER .
The SYSAUX tablespace is the new feature introduced in Oracle Database 10g. It serves as an auxiliary tablespace to the SYSTEM tablespace. Because it is the default tablespace for many Oracle Database features and products that previously required their own tablespaces. Continue Reading»
snoop- capture and inspect network packets
SYNOPSIS
snoop [-aqrCDNPSvV] [-t [r| a| d]] [-c maxcount] [-d device] [-i filename] [-n filename] [-o filename] [-p first[,last]] [-s snaplen] [-x offset[,length]] [expression]
snoop captures packets from the network and displays their contents. snoop uses both the network packet filter and streams buffer modules to provide efficient capture of packets from the network.
In Linux and Solaris Operating Sytems the Run levels are considered as more important.
If the Runlevels are used improperly then there will be problem in booting up and using the system.
Linux Run Levels
============
0 - halt (Do NOT set initdefault to this)
1 - Single user mode
2 - Multiuser, without NFS
3 - Full multiuser mode
4 - unused
5 - X11
6 - reboot (Don’t set this to default init level) Continue Reading»
The sar command is used to sample and report various cumulative statistic counters maintained by the operating system.
SYNOPSIS
sar [-dgpu] [-n mode] [-o filename] t [n]
sar [-dgpu] [-n mode] [-e time] [-f filename] [-i seconds] [-s time]
The sar command writes to standard output the contents of selected cumulative activity counters in the operating system. The accounting system, based on the values in the count and interval parameters, writes information the specified number of times spaced at the specified intervals in seconds. Continue Reading»
vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity.
The first report produced gives averages since the last reboot. Addi-tional reports give information on a sampling period of length delay.The process and memory reports are instantaneous in either case.
vmstat - Report virtual memory statistics
SYNOPSIS
vmstat [-a] [-n] [delay [ count]]
vmstat [-f] [-s] [-m]
vmstat [-S unit]
vmstat [-d]
vmstat [-p disk partition]
vmstat [-V]
vmstat does not require special permissions.
vmstat reports are intended to help identify system bottlenecks. Continue Reading»
The iostat command is used for monitoring system input/output device loading by observing the time the devices are active in relation to their average transfer rates. The iostat command generates reports that can be used to change system configuration to better balance the input/output load between physical disks.
iostat - Report Central Processing Unit (CPU) statistics and input/output statistics for devices and partitions.
SYNOPSIS
iostat [ -c | -d ] [ -k ] [ -t ] [ -V ] [ -x ] [ { device [ … ] | ALL} ] [ -p [ { device | ALL } ] ] [ interval [ count ] ]
Iostat command is veryuseful commands for system admins and DBA’s for anlaysing the system load . Continue Reading»
