System Settings

Configuration Settings #

Most options can be changed only in the configuration file or command line. Some options are read-only and represent the runtime state.

Session options can be changed using the SET command.

Main Settings #

Name Type Mode Description
uuid string cli Server ID
timezone string cli, session System and session timezone
format string cli, session System and session result format
shutdown string cli System shutdown mode: fast (default) or graceful. 
show uuid;
["a74fbf39-cc9d-314e-a33e-3aa47559ffe5"];

select system.config().uuid;
["a74fbf39-cc9d-314e-a33e-3aa47559ffe5"]

show format;
["json-pretty"]

Logger Settings #

Name Type Mode Description
log_enable bool cli Log messages
log_to_file bool cli Write log messages to file inside the base directory
log_to_stdout bool cli Duplicate log message to stdout
log_connections bool cli Log connect/diconnect client events
log_options bool cli Log configuration options on start 
show log_connections;
[true]

TLS Certificates #

Name Type Mode Description
tls_capath string cli TLS CA directory path.
tls_ca string cli TLS CA certificate file path.
tls_cert string cli TLS Server certificate file path.
tls_key string cli TLS Server certificate private key file path. 
show tls_cert;
[""]

select system.config().tls_cert;
[""]

Server Settings #

Name Type Mode Description
listen array cli Listen for incoming connections

Listen represent an array of objects, where following fields are recognized:

Argument Type Description
path string Unix socket file path.
path_mode string Unix socket file mode.
host string Listen address (using host or path is mandatory).
port int Listen port.
tls bool Enable TLS for this address.
auth bool Enable Authentication for this address. 
show listen;
[{
  "host": "*",
  "port": 3485,
  "auth": true,
  "tls": true
}]

select system.config().listen;
[{
  "host": "*",
  "port": 3485,
  "auth": true,
  "tls": true
}]

Session Limits #

Name Type Mode Description
limit_send int cli Limit for reply (bytes)
limit_recv int cli Limit for request (bytes)
limit_write int cli Limit for transaction log size (bytes) 
show limit_send;
[3145728]

show limit_recv;
[1048576]

show limit_write;
[0]

IO and Compute Workers #

Name Type Mode Description
frontends int cli Number of frontend workers
backends int init cli Number of backend workers. Can be changed only once on init, after that the DDL commands must be used 
show frontends;
[5]

WAL Settings #

Name Type Mode Description
wal_worker bool cli WAL worker thread for fsync() and file creation (enabled by default).
wal_crc bool cli Calculate and validate checksums during WAL write and read (enabled by default).
wal_sync_on_create bool cli Sync the WAL file together with the directory after creation (enabled by default).
wal_sync_on_close bool cli Sync the WAL file before closing (enabled default).
wal_sync_on_write bool cli Sync the WAL file on each write (disabled by default).
wal_sync_interval string cli Sync the WAL file every interval (“1 sec” by default).
wal_size int cli When the current WAL file reaches this value, a new file will be created.
wal_truncate int cli Truncate WAL files to the specified LSN value to recover invalid WAL files and bring them to a valid location after a crash (0 is disabled). This operation is potentially dangerous. To proceed, it is recommended that you create a copy of the WAL data first.

Replication Settings #

Name Type Mode Description
repl_readahead int cli The amount of data to read from WAL in bytes before sending it to the replica.
repl_reconnect_ms int cli Reconnect interval in ms 
show repl_reconnect_ms;
[3000]

show repl;
[{
  "active": false,
  "role": "primary",
  "primary": null
}]

Checkpoint #

Name Type Mode Description
checkpoint_interval interval cli 5 minutes by default
checkpoint_workers int cli Number of workers which will be created during checkpoint (3 by default)
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