Nine factors affecting database access speed

1. There is no index or no index database index is used, just like a directory in a book, so that users can find the desired data without having to traverse all the data when accessing the database data. After creating an index, You can ensure the uniqueness of each row of data and greatly improve the efficiency of data retrieval. This is a way to sacrifice space for performance. No index or no index is used, which is the most common cause of slow data access.ProgramA design defect.

2. Low I/O throughput, resulting in a bottleneck effect. I/O throughput is an objective factor (hardware factor) that affects data access speed ). In a certain hardware environment, the I/O throughput can be appropriately increased by using the optimized deployment scheme.

3. If no calculation column is created, the query is not optimized. The calculation column is a special column and is not of any design type. You cannot change the value of this column. The calculated column value is calculated by using a certain function formula and other values of another or more columns as the input values. If no calculation Column exists, you need to calculate existing data in some data queries, which wastes some performance.

4. insufficient memory will undoubtedly occupy a large amount of memory space for database data query and access. When the memory is insufficient, the data access speed will be significantly affected or even access times out, is an objective factor affecting data access speed.

5. slow network speed is an objective factor affecting data access speed. You can solve this problem by increasing the bandwidth of the network.

6. The queried data volume is too large. When the queried data volume is too large, the memory usage and system time usage all affect the data access speed. You can use multiple queries, locate queries, and query data volume control.

7. locks, deadlocks, or deadlocks may cause the visitor to wait for a period of time during database data access, or the user will never be able to obtain the resource. This is one of the most common causes of slow query. It is a defect in programming and should be avoided as much as possible.

8. when unnecessary rows and columns are returned in a general data query, as much data information as possible is obtained, resulting in unnecessary data traversal, this greatly increases the response time for data access. Therefore, in a general query, You can query as few rows and columns as possible to minimize the data Traversal Time to meet data output requirements.

9. The query statement is not optimized enough. During data query access, the most frequently used is the use of custom query statements for data output. Therefore, Writing optimized query statements can greatly speed up data query access.

Performance optimization database performance optimization is mainly to improve the speed of data access, that is, to improve the performance indicators of the database response speed. Performance Optimization consists of subjective and objective factors. The objective factors that affect performance are optimized here.