db2 performance tuning

:37YesOrchid Island Main 15:34:51Oh.Orchid Island Main 15:35:12Other, not quite understand your data in the situation, not very good fine optimization.Orchid Island Main 15:35:44Should still be quick.Snow Leopard 15:36:34GoodSnow Leopard 15:36:36Let me seeOrchid Island Main 15:37:16For example: The index of the other two tablesSnow Leopard 15:37:31WellOrchid Island Main 15:37:43The full table scan, although the table is small, but to 0.5s, should also be a small proportion.Snow Leopard 15:37:55I

. NET Performance Tuning series articles Series Article Index . NET Performance tuning: Use of the ANTS performance Profiler . NET Performance Tuning two: Code metrics with Vis

Cache Size| Query_cache_type | On | cache type, determines what queries are cached| Query_cache_wlock_invalidate | OFF | when other clients are writing to the MyISAM table If the query cache is returned , the cache result, or wait for the write operation to complete the reread table to get results+------------------------------+---------+Mysql> show global Status Like "qcache%";+-------------------------+-------+| variable_name | Value |+-----------------------

can avoid Key lookup is perfect, let's revise non-clustered index to include it in the index with the Include keyword His fields are:[SQL] DROP INDEX idx_non_clust_salesorddetaildemo_modifieddate on salesorddetaildemo GO CREATE nonclustered INDEX idx_non_clust_salesorddetaildemo_modifieddate on salesorddetaildemo (ModifiedDate) INCLUDE ( ProductID, UnitPrice ) GO --Clear the cache, only for the development environment! DBCC Freeproccache DBCC dropcleanbuffers GO

A basic knowledge1.1 What is performanceBefore performance tuning, let's start by understanding what performance is. With regard to performance, I think everyone who has studied Java can list a few points and even talk about it. In the Java TM Platform performance, the follo

Performance bottlenecks:Slow, write faster than read The main performance indicators:Frequency of visits,The number of concurrent connections,Cache Hit Ratio,Index use,Slow log opening and analysis,Query log, querying logThreads_cached: Whether the connection thread cache is turned onThread_cache_size: The size of the number of thread cachesQuery_cache_size: Query Cache SizeJoin_buffer_size:join Buffer Size

MySql Performance Tuning (5) demonstration of using a proper lock mechanism for table locks, mysql Tuning MySql locks take the following forms: 1. Table-level locks; low overhead, fast locking; no deadlock; large lock granularity, the highest probability of lock conflict, the lowest concurrency. The MyISAM engine belongs to this type. 2. Row-level locks: high ove

MySql Performance Tuning (4) Quick table structure modification and mysql Tuning 1. Modify the varchar type To meet your needs, change varchar (6) To varchar (8). A better method is not to use altertable modify, but to use the following steps: A. Create A temporary table and set varchar to varchar (8) as follows: B. Replace the. frm table stru

Build high performanceASP. NETSite Chapter 5-Performance Tuning Overview (previous) During this time, the seriesArticleI reorganized it. The previous introduction to performance optimization was not very clear. It can be said that starting from this article, it is the beginning of a complete series. Links to articles: Build high performanceASP. NETSit

DB2 database is locked for upgrade in the following two scenarios:1) when an app's lock is used by the memory >locklistxmaxlocks2) memory >locklist used by multiple application locksWhat happens if a lock is upgraded?As this is the mechanism of self-control of the database, we inadvertently enjoy the benefits of the same time, is often plagued by this mechanism. It is obvious that, once the system concurrency and

In use. NET to start and develop the application quickly, the next problem may be the performance tuning aspects of the program, and performance tuning can sometimes involve all aspects of the problem, such as the program host system, database, network environment, and so on, and when the program is unusually large and

buffer pool, but will eventually need to write these pages to disk. Some general I/O tuning steps can speed up this process when I/O to a page is written to disk, such as: Distribute tablespaces across multiple containers (these containers map to different disks). Use the fastest hardware and storage management configuration possible, which includes factors such as disk and channel speed, write caching, and parallel write. Avoid RAID5 (unless used wi

A graduation on the contact optimization problems, professional optimization also has at least 5 years of time, but now still often hear many people think that optimization is very simple, is to build index problem, it really can not blame everyone, do this line for more than 20 years, at every stage of career, almost can hear such a voice, In many books have also seen such a statement, but here I want to tell you: optimization is not just index, optimization is not very simple thing, this job r

High-performance ASP. NET Site build series Article Directories During this time, I reorganized the series of articles, and the previous introduction to performance optimization was not very clear. It can be said that starting from this article, it is the beginning of a complete series. The topics in this chapter are as follows: General performance

MySQL performance tuning and Architecture design--9th chapter The performance optimization of MySQL database schema designPreface: Many people think that performance is optimized in the process of writing code (program code or database code), in fact, this is a very big misunderstanding. The real impact of the most

JavaScript is a relatively complete front-end development language, in today's web development applications are very wide, especially for Web 2.0 applications. As Web 2.0 becomes more and more popular today, we will find that there will be a lot of JavaScript code in our Web application projects, and that there will be more and more in the future. JavaScript, as a language to interpret execution, and its single-threaded mechanism, determines that performance