RAM disk for the stats_temp_directory (original) (raw)

You can use the RDS for PostgreSQL parameter rds.pg_stat_ramdisk_size to specify the system memory allocated to a RAM disk for storing the PostgreSQLstats_temp_directory. The RAM disk parameter is only available in RDS for PostgreSQL version 14 and lower versions.

Under certain workloads, setting this parameter can improve performance and decrease I/O requirements. For more information about thestats_temp_directory, see the PostgreSQL documentation..

To set up a RAM disk for your stats_temp_directory, set therds.pg_stat_ramdisk_size parameter to an integer literal value in the parameter group used by your DB instance. This parameter denotes MB, so you must use an integer value. Expressions, formulas, and functions aren't valid for therds.pg_stat_ramdisk_size parameter. Be sure to reboot the DB instance so that the change takes effect. For information about setting parameters, see Parameter groups for Amazon RDS.

For example, the following AWS CLI command sets the RAM disk parameter to 256 MB.

aws rds modify-db-parameter-group \
    --db-parameter-group-name pg-95-ramdisk-testing \
    --parameters "ParameterName=rds.pg_stat_ramdisk_size, ParameterValue=256, ApplyMethod=pending-reboot"

After you reboot, run the following command to see the status of thestats_temp_directory.

postgres=> SHOW stats_temp_directory;

The command should return the following.

stats_temp_directory
---------------------------
/rdsdbramdisk/pg_stat_tmp
(1 row)