cassandra performance tuning

I. Preface Index plays an important role in database performance. The advantages and disadvantages of index design directly affect the efficiency of DB execution. Therefore, when performing DB tuning, some of them will start to process the index. SQL server also provides a good tool for Database Engine Tuning Advisor and provides some advice on index creation and

MySQL performance tuning and Architecture Design-Chapter 1 Basic Principles of scalable design, mysql Tuning Chapter 1 Basic Principles of scalable design Preface: With the rapid increase of information, the development of hardware equipment has gradually become unable to keep up with the application system's requirements for processing capabilities. How can we s

MySQL performance tuning and Architecture Design-the idea and solution of the High Availability design in Chapter 17th, mysql Tuning Chapter 1 High Availability design ideas and solutions Preface: The database system is the core part of an application system. To ensure the overall availability of the system, the database system cannot have any problems. For an en

MySql performance tuning policy and mysql tuning policy This topic provides detailed parameter descriptions for my. cnf configuration. The sample configuration is as follows: # Cat my. cnf # MySQL client library initialization. [Client] Port = 3306 Socket =/tmp/mysql. sock Character-set-server = utf8 # The MySQL server [Mysqld] Init_connect = 'set na

with a graphical performance detection tool. Ability to monitor memory, threads, class loading, virtual machine information, and moreVisual VM is a multi-in-one graphical performance detection tool that integrates a variety of new capability detection tools. Can replace some of the JDK's own tools, if JSTATE,JPS, etc.The Mat full name Memory Analyzer is a powerful Java heap analysis tool capable of analyzi

The main processes of tuning the JVM are:1. Determine heap memory size (-XMX,-XMS)2, the rational distribution of the new generation and old generation (-xx:newratio,-XMN,-xx:survivorratio)3. Determine the size of the permanent zone (-xx:permsize,-xx:maxpermsiize)4. Select the garbage collector5, the garbage collector to set reasonable6. Disable GC (-XX:+DISABLEEXPLICITGC)7. Disable class Metadata recycling (-XNOCLASSGC)8. Disable class validation (-x

:16TAB1 small, TAB2 billion level above, two weeks data in tens of millions of.Lan Hua Main 16:13:22Ok.Orchid Island Main 16:16:29So change the SQL:with T1 as (Select count (t.c1), t.c1,t.c2,t.c3,t.c4,t.c5From Tab1 twhere T.c2 not in (' Val1 ', ' val2 ', ' val3 ', ' val4 ', ' VAL5 ')and C1 is not NULLGroup by T.C1, T.C2,T.C3,T.C4,T.C5)Select T1.c1,t1.c2,t1.c3,t1.c4,t1.c5from T1Where NOT EXISTS (Select/*+ Use_hash (m,n) */M.C1, M.C2,M.C3,M.C4,M.C5from T1 m,tab2 Nwhere N.c2 > Sysdate-14and m.c1 =

Database Tuning tutorial (4) Explain performance analysis command, tuning explain In the previous chapter, we learned how to find slow queries and record statements into logs. How can we know where statement problems occur after slow queries are found. This chapter describes how to use the database performance analysis

Label:This paper mainly explains MySQL performance bottleneck analysis, performance indicators, performance index information collection tools and methods, analysis of the use of tuning tools.The article has not been completed, the following is an outline.Performance bottlenecks:SlowPerformance Index:Frequency of Visit

First, diagnostic tools 1. Warning Log file Warning log files contain system information and error logs that contain important errors (such as: ORA-600) and block checksum error messages (ora-1578,ora-1498). Monitor database operations such as CREATE DATABASE, STARTUP, SHUTDOWN, ARCHIVE log, and RECOVER, and record Non-default initialization parameter values. When Log_checkpionts_to_alert is set to true, the warning log file also records the start and end times of checkpoints, incomplete checkpo

The individual believes that JVM tuning is primarily addressed by the following methods1. Set the appropriate maximum heap memory (maximum and value for Cenozoic and Laosheng generations) and minimum heap memory (the operating system memory size consumed by JVM startup), and set the scale allocation of the heap.2, set up the suitable new generation because of its impact on the system performance and GC reco

Performance optimization is to improve the system performance, reduce energy usage, or reduce the impact of applications on other parts. If the optimization is hasty or there is no measurement, of course, performance optimization may have a bad effect. Performance optimization is to improve the system

Database Tuning tutorial (4) Explain performance analysis command, tuning explain In the previous chapter, we learned how to find slow queries and record statements into logs. How can we know where statement problems occur after slow queries are found. This chapter describes how to use the database performance analysis

: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

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

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

. 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