Manage Index 2 - Disadvantage Analysis

Index Disadvantages Analytical
indexes have some inherent deficiencies :
1. Build indexes. The system takes about 1.2 times the hard disk box memory space of the table to store the index.
2. When updating data, the system must have extra time to update the index at the same time to maintain the consistency of data and index.

Practice has shown that inappropriate indexing will not only not help, but will reduce system performance. Because a large number of indexes take more system time for insert, modify and delete operations than no index. For example, it should be inappropriate

to build an index on the following fields : 1. Fields that are rarely or never referenced ; 2. Logical fields, such as male or female (yes or no) and so on. To sum up, improving query efficiency comes at the expense of consuming a certain amount of system resources . Indexes cannot be created blindly. This is an important indicator for examining whether a DBA is excellent.