What are the considerations to bear in mind when using …

When using Parallel queries in Oracle, it is important to keep the following considerations in mind:

1. The use of parallel queries should be approached with caution, and it is only recommended to use parallel queries when conducting complex queries on large datasets.
2. Before executing parallel queries, it is essential to ensure that the database is properly configured. This involves correctly setting parallelism parameters and enabling appropriate hardware resources.
3. Running parallel queries can potentially consume a substantial amount of system resources, such as CPU, memory, and disk I/O. As a result, during parallel queries, there may be an impact on other users’ queries and transactions.
4. Parallel queries will generate additional logs and temporary data, so it is important to ensure there is enough disk space and I/O throughput to support parallel queries.
5. The effectiveness of parallel query execution depends on the characteristics of the query and the data distribution. Therefore, it is advisable to test and optimize before using parallel queries to ensure optimal performance.
6. Parallel queries may result in issues with data distribution and sorting. Before using parallel queries, it may be beneficial to consider creating indexes or partitions to improve query performance.
7. Regular monitoring and adjustment of database resources during parallel queries execution is necessary to prevent deadlocks and resource contention issues.
8. The degree of parallelism for parallel queries should be adjusted based on actual circumstances. A higher degree of parallelism may lead to wastage of resources, while a lower degree may not fully utilize system resources.

In conclusion, when using parallel queries, it is important to carefully evaluate and plan to ensure proper configuration of database and hardware resources, optimize and test queries to achieve optimal performance and reliability.