How to adjust the Oracle database

After a long period of development in Oracle, many users are familiar with Oracle database adjustment. Here I will share my personal understanding and discuss it with you. The Oracle database is adjusted in the Oracle database operation phase. The Oracle Database adjustment in the Oracle database operation phase includes two aspects:
◆ OS-level adjustment
◆ Adjust the Oracle database level

1. Operating System Adjustment

The main purpose of implementing OS-level adjustments is to reduce memory swap and paging so that SGA (SystemGlobleArea) can stay in memory.

1.1 reduce memory Switching

Memory swap swapping) may cause a large memory overhead, it should be minimized. For Oracle databases running on the SolarisUnix operating system, you can use vmstat or sar commands to check and exchange the system-level memory and hard disk I/O usage, adjust parameters such as the size of the unix data buffer pool and the memory size that each process can use.

Vmstat command

It reports the activity of processes, virtual memory, disks, pages, and CPUs on Solaris. The following command will display the summary of what the system does every five seconds: % vmstat5

Sar command

Monitors swap, paging, disk, and CPU activity. The following command displays a summary of 10 paging activities every 10 seconds: % sar-p1010

If the system memory exchange is large and memory saving is required, the following measures can be taken:
1) Avoid running unnecessary system daemon processes or application processes;
2) Reduce the number of Oracle Database buffers without significantly affecting the data block hit rate to release some memory;
3) Reduce the number of UNIX file buffers, especially when using bare devices ).

1.2 control Paging

A small amount of memory paging does not significantly affect the system performance, because applications do not have to be fully stored in the memory. However, too many pages will cause the system performance to decline. To detect too many pages, you can run the measurement during fast response or idle time and compare it with the measurement during slow response. You can solve this problem by using the following methods:
◆ Use vmstat or sar-p monitoring pagination;
◆ Install more memory;
◆ Move some work to another system;
◆ The core of the Configuration System uses less memory;

Keep the SGA in a single shared memory segment.

1.3 keep SGA (SystemGlobleArea) in memory

SGA is a global system zone for quick access to Oracle database data. If SGA needs to be released and allocated frequently, it is impossible to quickly access data. Therefore, the SGA memory is required to reside. At this time, we can reconfigure the UNIX core and adjust some operating system parameters to increase the shared memory. The preceding section describes how to adjust the Oracle database level.

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