Database Smart Flash Cache resides on one or more flash disk devices, which are solid state storage devices that use flash memory. It can improve response time and overall throughput for both read-intensive online transaction processing (OLTP) workloads and ad hoc queries and bulk data modifications in a data warehouse environment. Database Smart Flash Cache is an extension of the SGA-resident buffer cache, providing a level 2 cache for database blocks. If your database is running on Solaris or Oracle Linux, you can optionally add another memory component: Database Smart Flash Cache. The total PGA memory allocated for all background and server processes attached to an Oracle Database instance is referred to as the total instance PGA memory, and the collection of all individual PGAs is referred to as the total instance PGA, or just instance PGA.įigure 6-1 illustrates the relationships among these memory structures.įigure 6-1 Oracle Database Memory Structuresĭescription of "Figure 6-1 Oracle Database Memory Structures"
Background processes also allocate their own PGAs. There is one PGA for each server process.
Access to the PGA is exclusive to the server process. It is nonshared memory created by Oracle Database when a server process is started. Examples of data stored in the SGA include cached data blocks and shared SQL areas.Ī PGA is a memory region that contains data and control information for a server process. The SGA is shared by all server and background processes. The SGA is a group of shared memory structures, known as SGA components, that contain data and control information for one Oracle Database instance. The basic memory structures associated with Oracle Database include: Understand basic memory structures associated with Oracle Database. If you choose advanced installation, then DBCA enables you to select automatic memory management or automatic shared memory management. When system memory is greater than 4 gigabytes, automatic memory management is disabled, and automatic shared memory management is enabled. If you create your database with Database Configuration Assistant (DBCA) and choose the basic installation option, automatic memory management is enabled when system memory is less than or equal to 4 gigabytes. These memory management methods are described later in this chapter.
#MEM PATCH MEANING MANUAL#
Manual PGA memory management - for the instance PGA Manual shared memory management - for the SGAĪutomatic PGA memory management - for the instance PGA These methods are:Īutomatic shared memory management - for the SGA The methods therefore vary in the amount of effort and knowledge required by the DBA. Some of these methods retain some degree of automation. There are a few different methods available for manual memory management. If you prefer to exercise more direct control over the sizes of individual memory components, you can disable automatic memory management and configure the database for manual memory management.