db2 performance tuning tips mainframe

the data processing to the SSAS Cube Dimension (also disk files), again generate unequal disk overhead, in addition to distinct to recalculate, the former need to the membership dimension of this large table to do tier to heavy, the latter only need to the membership level this small dictionary table to do the heavy, obviously the calculation is different weight class, These are just the cost of the process, perhaps you are doing in the night, not care these, then the

The DB2 tutorial you're looking at is: Tips for improving Insert performance in DB2 (1). Overview of the INSERT processing processFirst let's take a quick look at the process steps when inserting a row. Each of these steps has the potential to optimize, which we will discuss later. Prepare the statement on the c

Tags: process optimizer consolidation requires merging auto overwrite session accessThe full execution order of the SELECT statement:The full execution order of the SQL SELECT statement: 1. The FROM clause assembles data from different data sources; 2. The WHERE clause filters the record rows based on the specified criteria, 3, the GROUP BY clause divides the data into multiple groupings, 4, uses the aggregation function for the calculation, 5, uses the HAVING clause to filter the grouping; 6, e

an execution plan, and stored in a database of SQL statements, is a collection of control flow language, the speed of course fast. 48, the return value of the function is not too large, this overhead is very large. A user-defined function that executes as a cursor consumes a large amount of resources if a large result is returned with a stored procedure. 49, as far as possible to avoid repeated access to the same or several tables, especially the large number of data tables, you can consider th