Configuring Presto#

Presto configuration parameters can be modified to tweak performance or add/remove features. While Presto is designed to work well out-of-the-box, you still may need to make some changes.

Memory configuration#

It is often necessary to change the default memory configuration based on your cluster’s capacity. The default max memory for each Presto server is 16 GB, but if you have a lot of memory (say, 120GB/node), you may want to allocate more memory to Presto for better performance.

In order to update the max memory value to 60 GB per node:

Change the line in ~/.prestoadmin/coordinator/jvm.config and ~/.prestoadmin/workers/jvm.config that says -Xmx16G to -Xmx60G.
Change the following lines in ~/.prestoadmin/coordinator/config.properties and ~/.prestoadmin/workers/config.properties:
```
query.max-memory-per-node=8GB
query.max-memory=50GB
```
to
```
query.max-memory-per-node=30GB
query.max-memory=<30GB * number of nodes>
```
We recommend setting query.max-memory-per-node to half of the JVM config max memory, though if your workload is highly concurrent, you may want to use a lower value for query.max-memory-per-node. If you have large data skew, query.max-memory-per-node should. By default in Presto 148t and higher, query.max-memory-per-node is 10% of the Xmx value specified in jvm.config.
Run the following command to deploy the configuration change to the cluster:
```
./presto-admin configuration deploy
```
Restart the Presto servers so that the changes get picked up:
```
./presto-admin server restart
```
If you are running Presto in a test environment that has less than 16 GB of memory available, you will need to follow similar procedures to set the memory configurations lower.

Log file location configurations#

For most production environments, it will be necessary to change the log locations. In order to update these:

Stop the Presto server.
```
./presto-admin server stop
```
Presto stores logs and other data in node.data-dir, node.launcher-log-file, and node.server-log-file. It is very important that these locations have enough space for the logs on the filesystem on each node where Presto is running. The default location for node.data-dir is /var/lib/presto/data, the default location for node.launcher-log-file is /var/log/presto/launcher.log, and the default location for node.server-log-file is /var/log/presto/server.log. Assuming the chosen locations are /data1/presto and /data2/presto for the data directory and server logs respectively, the properties in ~/.prestoadmin/coordinator/node.properties and ~/.prestoadmin/workers/node.properties will be as follows:
```
node.data-dir=/data1/presto/data
node.launcher-log-file=/data2/presto/launcher.log
node.server-log-file=/data2/presto/server.log
```
The log directory(ies) (in the above example, /data1/presto and /data2/presto; the data directory for node.data-dir is created by Presto) need to exist on all nodes and be owned by the presto user. The command presto-admin run_script can be used to perform these actions on all of the nodes. First, create a script in the same directory as presto-admin, called script.sh:
```
#!/bin/bash
mkdir -p /data1/presto
mkdir -p /data2/presto
chown presto:presto /data1/presto
chown presto:presto /data2/presto
```
Then, run the following command:
```
./presto-admin run_script script.sh
```
Run the following command to deploy the log configuration change to the cluster:
```
./presto-admin configuration deploy
```
Restart the Presto servers so that the changes get picked up:
```
./presto-admin server restart
```

For detailed documentation on configuration deploy, see configuration deploy. For more configuration parameters, see the Presto documentation.