# Oracle Database - PARALLEL_MAX_SERVERS parameter

This parameter determines the maximum number of parallel servers that may be started for a database instance, should there be demand for them.

The default value on Oracle Database 10g and higher is:

$$\text{PARALLEL MAX SERVERS} = 10 * \text{cpu count} * \text{parallels threads per cpu}$$

where:

## Rule of thumb

A good rule of thumb is to ensure parallel_max_servers is set to a number greater than : $$\text{parallel_max_servers} > \text{maximum number of concurrent queries} * \text{maximum degree of parallelism need by a query}$$ where:

By doing this you will ensure every query gets the appropriate number of parallel servers.