Setting a single parameter is a great way to get there.įor the novice user wanting to play with parallel query for the first time, parallel automatic tuning is a good way to get started. I have found that, for most cases, this achieves my desired goal, which is usually to get the best performance, with the least amount of work, in a manner that is most manageable. The degree of parallelism (how many processes/threads will be thrown at a problem) will be decided for me and vary over time as the load on the system varies. Now, all I need to do is set the PARALLEL option on the table (not PARALLEL, just PARALLEL) and Oracle will, when appropriate, parallelize certain operations on that table for me. With this setting, the other parallel settings are automatically set. As I mentioned earlier, my current favorite way to set up parallelism in Oracle is using the automatic tuning option first introduced in Oracle8i Release 2 (version 8.1.6): PARALLEL_AUTOMATIC_TUNING = TRUE. That topic is well covered in both the Oracle Concepts Guide and Data Warehousing Guide. I will not discuss the physical setup of parallel query operations. Parallel query is my last path of action for solving a performance problem it's never my first course of action. Parallel query is suitable for a certain class of large problems: very large problems that have no other solution. Here is a short quote from my book Effective Oracle by Design on this topic: That you use the automatic parallel tuning.
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