Configuration

This guide covers the configuration files and the SET statement.

Configuration Files

By default, configuration files are stored in /etc/sqream.

A very minimal configuration file looks like this:

{
    "compileFlags": {
    },
    "runtimeFlags": {
    },
    "runtimeGlobalFlags": {
    },
    "server": {
        "gpu": 0,
        "port": 5000,
        "cluster": "/home/sqream/sqream_storage",
        "licensePath": "/etc/sqream/license.enc"
    }
}
  • Each SQream DB worker (sqreamd) has a dedicated configuration file.
  • The configuration file contains four distinct sections, compileFlags, runtimeFlags, runtimeGlobalFlags, and server.

In the example above, the worker will start on port 5000, and will use GPU #0.

Frequently Set Parameters

Server flags
Name Section Description Default Value range Example
gpu server Controls the GPU ordinal to use ✗ 0 to (number of GPUs in the machine -1). Check with nvidia-smi -L "gpu": 0
port server Controls the TCP port to listen on ✗ 1024 to 65535 "port" : 5000
ssl_port server Controls the SSL TCP port to listen on. Must be different from port ✗ 1024 to 65535 "ssl_port" : 5100
cluster server Specifies the cluster path root ✗ Valid local system path "cluster" : "/home/sqream/sqream_storage"
license_path server Specifies the license file for this worker ✗ Valid local system path to license file "license_path" : "/etc/sqream/license.enc"
Runtime Global Flags
Name Section Description Default Value range Example
spoolMemoryGb runtimeGlobalFlags Modifies RAM allocated for the worker for intermediate results. Statements that use more memory than this setting will spool to disk, which could degrade performance. We recommend not to exceed the amount of RAM in the machine. This setting must be set lower than the limitQueryMemoryGB setting. 128 1 to maximum available RAM in gigabytes. "spoolMemoryGb": 250
WriteToFileThreads runtimeGlobalFlags Configures the number of threads in the WriteToFile function 16    
limitQueryMemoryGB runtimeGlobalFlags Modifies the maximum amount of RAM allocated for a query. The recommended value for this is total host memory / sqreamd workers on host. For example, for a machine with 512GB of RAM and 4 workers, the recommended setting is 512/4 → 128. 10000 1 to 10000 "limitQueryMemoryGB" : 128
cudaMemQuota runtimeGlobalFlags Modifies the maximum amount of GPU RAM allocated for a worker. The recommended value is 99% for a GPU with a single worker, or 49% for a GPU with two workers. 90 % 1 to 99 "cudaMemQuota" : 99
showFullExceptionInfo runtimeGlobalFlags Shows complete error message with debug information. Use this for debugging. false true or false "showFullExceptionInfo" : true
initialSubscribedServices runtimeGlobalFlags Comma separated list of service queues that the worker is subscribed to "sqream" Comma separated list of service names, with no spaces. Services that don’t exist will be created. "initialSubscribedServices": "sqream,etl,management"
logClientLevel runtimeGlobalFlags Used to control which log level should appear in the logs 4 (INFO) 0 SYSTEM (lowest) - 4 INFO (highest). See information level table for explanation about these log levels. "logClientLevel" : 3
nodeInfoLoggingSec runtimeGlobalFlags Sets an interval for automatically logging long-running statements’ SHOW_NODE_INFO output. Output is written as a message type 200. 60 (every minute) Positive whole number >=1. "nodeInfoLoggingSec" : 5
useLogMaxFileSize runtimeGlobalFlags Defines whether SQream logs should be cycled when they reach logMaxFileSizeMB size. When true, set the logMaxFileSizeMB accordingly. false false or true "useLogMaxFileSize" : true
logMaxFileSizeMB runtimeGlobalFlags Sets the size threshold in megabytes after which a new log file will be opened. 20 1 to 1024 (1MB to 1GB) "logMaxFileSizeMB" : 250
logFileRotateTimeFrequency runtimeGlobalFlags Control frequency of log rotation never daily, weekly, monthly, never "logClientLevel" : 3
useMetadataServer runtimeGlobalFlags Specifies if this worker connects to a cluster (true) or is standalone (false). If set to true, also set metadataServerIp true false or true "useMetadataServer" : true
metadataServerIp runtimeGlobalFlags Specifies the hostname or IP of the metadata server, when useMetadataServer is set to true. 127.0.0.1 A valid IP or hostname "metadataServerIp": "127.0.0.1"
useConfigIP runtimeGlobalFlags Specifies if the metadata should use a pre-determined hostname or IP to refer to this worker. If set to true, set the machineIp configuration accordingly. false - automatically derived by the TCP socket false or true "useConfigIP" : true
machineIP runtimeGlobalFlags Specifies the worker’s external IP or hostname, when used from a remote network. No default A valid IP or hostname "machineIP": "10.0.1.4"
tempPath runtimeGlobalFlags Specifies an override for the temporary file path on the local machine. Set this to a local path to improve performance for spooling. Defaults to the central storage’s built-in temporary folder A valid path to a folder on the local machine "tempPath": "/mnt/nvme0/temp"
Runtime Flags
Name Section Description Default Value range Example
insertParsers runtimeFlags Sets the number of CSV parsing threads launched during bulk load 4 1 to 32 "insertParsers" : 8
insertCompressors runtimeFlags Sets the number of compressor threads launched during bulk load 4 1 to 32 "insertCompressors" : 8
statementLockTimeout runtimeGlobalFlags Sets the delay in seconds before SQream DB will stop waiting for a lock and return an error 3 >=1 "statementLockTimeout" : 10

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Changing Settings Temporarily

The SET statement can modify one of the configuration settings for the session or connection.

For example, to set the query plan’s logging interval to “every 3 seconds” for subsequent statements:

t=> SET nodeInfoLoggingSec=3; SELECT * FROM nba;