A monitoring software called PIGOSS, it monitors the Oracle database very well. It can sort the SQL statements that occupy more disk IO and read and write times to TOP5, and it is easy to find the SQL statements that occupy more resources . This software is made in China and the price is lower.
There is no upper limit on the number of ORACLE connections in theory, and you can set as many as you want. In fact, it is related to the configuration of the server. The stronger the configuration, the higher the upper limit of the number of connections that can be set.
My current system is set to 3000, of course, the server configuration is also quite strong.
Xiaosheng's time to study on the oracle database is not short, and now I will summarize my experience.
In my opinion, the performance of the database mainly depends on two parts: database management and sql statements. In addition to the optimization theory in textbooks, database optimization needs to be based on specific situations.
1. Database
management The performance problems of the database are mainly reflected in:
1. Insufficient hardware resources. Such as CPU, memory, I/O, network 2, resource design is unreasonable. Such as unreasonable SGA allocation, low hit rate 3, insufficient lock resources.
Below we will provide a variety of methods to analyze these issues. The database in this article is oracle 10g and OLAP system
1.1. Check hardware resources.
Note that the time point should be selected during the busy time of the database.
1.1.1 View host configuration
uname –M -- IBM,9117-MMA prtconf | grep proc |wc –l -- 16 cpu prtconf –s -- Processor Clock Speed: 5008 MHz prtconf –m -- Memory Size: 254208 MB
1.1.2 Machine stress test
vmstat 10 10
We can see that the idle is around 1%, and there is no waiting.
1.1.3 Network and storage stress test The
topas
eno traffic is above 8M, and the en4 is above 1M. (en-Ethernet) Busy disks are already 100%.
1.2 Database Analysis
1.2.1 Database Analysis Report
The database analysis report can give you a comprehensive understanding of your database, which can be generated by statspack and AWR tools. There are many tutorials in this area, and this article will not repeat them. This article mainly analyzes the database for users without DBA privileges.
1.2.2 Understand the SGA status and view the SGA allocation
SELECT* from v$parameter a WHERE a.name IN( 'shared_pool_size' , 'log_buffer', 'db_cache_size', 'java_pool_size','large_pool_size')
View SGA usage
select component,current_size/1048576 ,min_size/1048576 from v$ sga_dynamic_components;
1.2.3 Understand the PGA status
PGA=UGA+sort_area_size + hash_area_size+ bitmap_merge_area_size sort_area_size : The total amount of memory used
to sort information sort_area_retained_size : The total amount of memory to store sorting information in memory after sorting. hash_area_size : The amount of memory used to store the hash list.
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Query the total size of PGA, the result is 24G. SQL>
SQL> select round(sum(pga_alloc_mem)/1048576,1) from v$process;
ROUND(SUM(PGA_ALLOC_MEM)/10485 ------------------------------
4424.1