분류 전체보기351 ORACLE TO TERADATA MIGRATION GUIDELINES Primary Index creation rules: OracleTeradataPRIMARY KEYMake UPI and change those columns to NOT NULL.No PRIMARY KEY but one or more UNIQUE indexesCreate UPI with unique index with the least number of columns. Maintain NULL/NOT NULL constraint as is.No PRIMARY KEY, no Unique indexes, but only non-unique indexesPick a good candidate for PI and create NUPI. Maintain NULL/NOT NULL constraint as is.N.. 2014. 4. 28. Performance tuning #1 출처: http://www.teradatatips.com/2010/07/performance-tuning-1.html I have taken a long break from updating this blog. To appease my mind, I am going to update a series of posts for Performance tuning, as it is going on in my project work. When it comes to performance tuning, we cannot stick to a certain set of rules. It varies based on the data you are dealing with. Although, we can create a base.. 2014. 4. 24. Teradata Performance Tuning - Basic Tips Performance tuning thumb rules. Here are very basic steps which are used to PT any given query in given environment . As a pre-requiste , make sure - user has proper select rights and actual profile settings - Enough space available to run and test the queries 1. Run explain plan (pressing F6 or "EXPLAIN sel * …",) Then see for potential information like - No or low confidence - Product joins co.. 2014. 4. 24. Teradata SQL Query Optimization Or Performance Tuning SQL and Indexes : 1) Primary indexes: Use primary indexes for joins whenever possible, and specify in the where clause all the columns for the primary indexes. 2) Secondary indexes (10% rule rumor): The optimizer does not actually use a 10% rule to determine if a secondary index will be used. But, this is a good estimation: If less than 10% of a table will be accessed if the secondary index is u.. 2014. 4. 24. 이전 1 ··· 69 70 71 72 73 74 75 ··· 88 다음