oracle performance tuning tips

of disk sorting will be greatly increased. This is mainly because at the end of the month, users will make statistics on the transaction data for the month. So at the beginning of the month, because of the number of transactions, so there will be more disk sorting occurs. In this case, it is necessary for the database administrator to adjust the relevant parameters. However, this adjustment is a temporary adjustment, until the cycle has passed, still need to transfer the parameters back. Only i

, which can significantly improve performance. Experience shows that the biggest improvement in SQL Server performance is due to logical database design, index design, and query design. Conversely, the biggest performance problems are often caused by deficiencies in these same areas. In fact, the essence of SQL optimization is that the result is correct, with th

prevents people from overwriting the length () method. In addition, if you specify a class to be final, all methods of that class are final. the Java compiler will look for opportunities for inline (inline) all final methods ( This is related to the specific compiler implementation ). This will increase the performance on average 50%. 1.6 Use local variables as much as possibleparameters that are passed when the method is called and temporary varia

/how-to-drastically-improve-your-app-with-an-afternoon-and-instruments) There are some code that can be used to parse the ISO-8601 date string, and simply rewrite it to use it.Well, just use C to make it look good, but do you believe that we have a better plan!If you can control the date format you are working with, try to choose a Unix timestamp. You can easily convert from timestamp to NSDate: -(nsdate*return[NSDate datewithtimeintervalsince1970:timestamp];}This will be faster than using C

filtering out unwanted records before group by. The following two queries return the same result but the second one is significantly faster.The code is as follows:Low efficiency:SELECT JOB, AVG (SAL)From EMP GROUP job has job = ' president ' and AVG (SAL) >xxxEfficient:SELECT JOB, AVG (SAL)From EMPWHERE JOB = ' President 'OR job = ' MANAGER ' GROUP JOB having and AVG (SAL) >xxx7, usually, if the statement can avoid the use of subqueries, as far as possible without sub-query.Because the overhead

. Create_snapshot; We can also use the Dbms_workload_repository package to complete the baseline, the default settings and other operations.ADDM (Automatic Database diagnostic Monitor AWR)Oracle is an internal consulting system, can automatically complete the most database of some optimization recommendations, giveSQLThe optimization, the creation of the index, the collection of statistics and other suggestions.ADDM report Generation:Sqlplus>@?/rdbms/

some code that can be used to parse the ISO-8601 date string, and simply rewrite it to use it.Well, just use C to make it look good, but do you believe that we have a better plan!If you can control the date format you are working with, try to choose a Unix timestamp. You can easily convert from timestamp to NSDate:-(nsdate*) Datefromunixtimestamp: (nstimeinterval) timestamp {return [nsdate Datewithtimeintervalsince1970:timestamp]; }This will be faster than using C to parse the date string!It is

) name:@"IdleNotification" object:nil]; NSNotification *notification = [NSNotification notificationWithName:@"IdleNotification" object:nil]; [[NSNotificationQueue defaultQueue] enqueueNotification:notification 　　postingStyle:NSPostWhenIdle];} Five, memory optimization Use Autorelease pool to reduce memory spikes Six, Code details optimization 1, not in the viewwillapear time-consuming operation 2. If the key code is more efficient with C/C + + Seven, picture optim

Absrtact: By discussing and studying the characteristics and principles of Oracle Server and Client/server, this paper expounds some principles and methods of improving and adjusting the performance of Oracle Application system. Keywords: Oracle; client/server; system whole zone; network I/O; rollback segment.

so that you can mark the snapshot information set at important times. A baseline is defined between a pair of snapshots, and the snapshot is identified by their snapshot sequence number. eachThe baseline has only a couple of snapshots. A typical performance tuning practice starts with collecting baseline collections of metrics, making changes, and then capturing another set of baselines. You can compare th

the deterioration of performance is a variety of factors, and sometimes the results of the performance degradation caused by multiple elements, this requires the database administrator has a more comprehensive computer knowledge, can be sensitive to the impact of the database performance of the main reason. In addition, good database management tools are also im

"Performance Tuning" Oracle AWR reporting metrics full resolution What is AWR? ===================================================================================================== AWR (Automatic workload Repository) A bunch of historical energy data, placed on the Sysaux table space, AWR and Sysaux are all 10g, are the key features of

Windows 2000 TCP Performance Tuning tips Carl HarrisCommunications Network servicesvirginia tech I was dismayed by the rather dismal TCP Performance in Win2000, especially for FTP up/downloads to distant sites, where the round-trip time (RTT) is nearly triple-digit. being a Unix bigot of sorts, I also found it amusing

Io is very relevant, when the free buffer waiting in the v$session_wait of the entry is very small or not, Explain the DBWR process of your system will be enough, do not need to adjust, there are many items of free buffer wait, your system must feel very slow, then your DBWR is not enough, the resulting wio has become your database performance bottlenecks, the solution is as follows: A.1 to increase the write process while adjusting the db_block_lru_

Tags: Practice login 16px between multiple connect shut down database SQL business logic　　The end of 2016 was the stage where I learned to understand the entire front end, backend, and database programming. During the practice programming process, notice that there is a scene between the server and the database: Start linking Database SQL--- $loginin =mysql_connect ("192.168.10.253:3306", "root", "123456"); To the end of the entire business logic, do not add a channel that closes the SQL linked