db2 sql performance tuning

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

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

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

Outline: I. Overview 2. What is performance tuning? (What) 3. Why performance optimization? (Why) 4. When do I need performance optimization? (When) 5. Where do I need performance tuning? (Where) 6. Who will perform

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

daily data calculation is only 20 minutes, but if I want to count the whole month, The system takes more than 10 hours (SQL statements degrade performance in the presence of large data volumes). This divide-and-conquer approach helps performance in the face of big data, just like the merge sort. Performance optimizati

user trace file records the statistics that are executed by a user's SQL statement. Start user tracking can be at the instance level and session level. Instance level: Sets the Sql_trace initialization parameter to TRUE and generally does not advocate tracking user actions at the instance level Session level: Executes the dbms_system.set_sql_trace_in_session function, as follows EXECUTE dbms_system.set_sql_trace_in_session (8,12,true); The Dbms_syste

Performance Tuning overview: I. Overview 2. what is performance tuning? (What) 3. Why performance optimization? (Why) 4. When do I need performance optimization? (When) 5. where do I need per