wait event

1. Read the data of indexkey to the cache. If this part of data is not read to DBCache, dbfilescatterreadwrite wait events may occur. 2. Sort the data of indexkey. If sort_area_size or pga_aggregate_target is not large, disksort may be performed. 1.

Among the many Oracle problems, the most important one is the buffer busy wait (buffer busy wait) event. Buffer busy waiting is the most common phenomenon in the I/O-bound Oracle system, especially in the first five busy (sequential/distributed)

Oracle11Gdirectpathread is very beautiful and hurtful.Direct path read In 11g, full table scan may use direct path read to bypass the buffer cache. Such full table scan is physical read. In 10 Gbit/s, it is read through gc buffer, so there is no

The database encountered the problem of enq: TX-row lock contention. This morning, we made an awr report and the database encountered a lot of waiting events for enq: TX-row lock contention, it feels strange. Query the wait event in gv $ session

When tuning an Oracle database, each component has its own set of statistics. to look at the system as a whole, it is necessary to have a common scale for comparisons. for this reason, most Oracle Database advisories and reports describe statistics

Windows Background Services Program Authoring1. Why to write a background service programThere is a program in the work to be written in the form of back-office services, groping a bit, share with you.In the Windows operating system, a background

both are common design patterns in concurrent programming for separating and distributing I/O events, but slightly different:The Proactor is used for asynchronous I/O operations, while reactor is used for synchronous I/O operations. typical reactor

first of all continue to recall that, before the execution of the sub-thread has a content that is not involved ngx_process_events_and_timers, today we will study this function. This post is from:http://blog.csdn.net/lengzijian/article/details/7601

I. Conditions for triggering DBWR Disk Data Writing 1. when a process scans the secondary LRU and primary LRU linked lists to find the buffer header that can be overwritten [idle buffer, if the number of buffer headers that have been scanned reaches

Enqueue is a lock mechanism to protect shared resources. This locking mechanism protects shared resources, such as recorded data, to prevent two people from updating the same data at the same time. EnqueueIt includes a queuing system, namely, the

(Original)I bought the 2007.4 issue of programmer magazine yesterday and read it for the first time. One of the two high-performance I/O design patterns is eye-catching, this is a translation. I have been trying to carefully read this article for a

You can use utlbstat and utlestat to obtain the performance difference report and analyze the report to determine the information that mainly affects the system. however, due to the uncertainty of performance differences between two points, such as

Oracle SQL tracking method: 1. SQL _trace Enable tracking: Alter session set SQL _trace = true; Mark the trace file: Alter session set tracefile_identifier = 'look _ for_me '; Stop tracking: Alter session set SQL _trace = false; You can use the

-- Main Waiting ViewSelect * from V $ session_wait;Select * from V $ session_event;Select * from V $ system_event;Select * from V $ waitstat where count> 0; -- Related viewSelect * from V $ session_wait Select * from V $ filestat Select * From

This problem is found in a database in the customer environment. At that time, the customer asked for help, the database status is not normal, connected to the database can not operate normally, and sometimes error ORA-12537 error. ORA-12537: TNS:

When the data block in the buffer cache is modified, the server process generates redo data and writes it to the redo log buffer. When the following conditions are met, LGWR will write the entries in the redo log buffer into the online redo log:--

Document directory Sample Code Device management Select the video card to use Run the computing coloring Tool Resources in DirectCompute Computing coloring machine (CS) HLSL Programming Note: DirectX has always been the core technology of

In the previous two articles, the author introduced how to useIPhone applicationsThe page template is inAxure, a prototype design toolAnd how to view the iPhone app prototype on the iPhone. Next, I will explain how to use axure to set upShow and

Recently, I just made a performance optimization job. According to the statspack report of one week, I wrote an optimization solution. I. Existing major performance problems of the systemAccording to the typical statspack report in the last week,

Io OptimizationIn the case of massive data, more than 80% of database performance problems are related to Io, So I/O optimization is an important task throughout the whole process of massive database management.I/O optimization involves a wide range