Configuration When Presto Uses Heap and Off-Heap Memory

Presto Administration : Presto Server Configuration : Memory Configuration for the Presto Server : Configuration When Presto Uses Heap and Off-Heap Memory

Presto should be configured to use both heap and off-heap memory only when the available memory supports this adequately and you have also installed BigMemory Servers.

Note:

You must have installed a copy of your BigMemory license in Presto to use off-heap memory. See Manage Licenses for Presto, Universal Messaging and BigMemory for instructions.

With combination heap and off-heap memory, as this figure shows, BigMemory uses off-heap memory for the Presto Analytics In-Memory Stores and Presto caches. All other Presto processing, including the Integrated MashZone Server and Event Service that are deployed with Presto, remains in heap.

The total available off-heap memory may be limited to local off-heap memory as shown above, or it may include additional off-heap memory on external hosts if you have installed BigMemory Server arrays.

Note:

For more information and suggestions on memory requirements for the Integrated MashZone Server and Event Service, see Tune Memory/Caching for the Integrated MashZone Server.

To update memory configuration:

1. In a text editor of your choice, open the application server configuration file appropriate for your operating system:

presto-install/apache-tomee-jaxrs/bin/setenv.bat, for Windows

presto-install/apache-tomee-jaxrs/bin/setenv.sh, for Linux, OS/X or UNIX

2. Change or add either of these memory options used with BigMemory:

-Dpresto.bm.maxOffHeap	Default = 1G This is the maximum size of local off-heap memory that BigMemory can use for the Presto Analytics In-Memory Stores and Presto caches. This property sets off-heap memory limits in the presto-config/ehcache.xml configuration file. The total size of off-heap memory may include additional, external memory depending on how BigMemory is deployed.
-XX:MaxDirectMemorySize	Default = 1500M This Java memory option must be set to allow access to both off-heap and an additional allocation for Java. The value of this option must always be larger than the memory allocated to off-heap. A good rule of thumb is at least 500M more.

3. Change or set any of these Java memory options:

-Xms	Default = 512M
-Xmx	Default = 1G See the Java Tuning White Paper for more information and suggestions.
-XX:PermSize	Default = 128M
-XX:MaxPermSize	Default = 256M

4. Save your changes and restart the Presto Server. See Start and Stop the Presto Server for instructions.

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