Load History System Tables

CedarDB collects metrics on system usage. These metrics include CPU usage, network usage, disk usage for the disk the database resides on, as well as some CedarDB-internal metrics.

These metrics are exposed through system tables, and can be queried through sql:

select * from cedardb_cpu_load_history
order by timestamp desc
limit 10;

           timestamp           | cpu_load
-------------------------------+-----------
 2026-09-08 14:09:51.552458+02 |       2.1
 2026-09-08 14:09:41.552465+02 |      2.06
 2026-09-08 14:09:31.552557+02 |      1.37
 2026-09-08 14:09:21.552383+02 | 1.5500001
 2026-09-08 14:09:11.552349+02 |       1.4
 2026-09-08 14:09:01.552454+02 | 1.5799999
 2026-09-08 14:08:51.552497+02 | 1.5899999
 2026-09-08 14:08:41.552507+02 |      1.77
 2026-09-08 14:08:31.552545+02 |      2.23
 2026-09-08 14:08:21.552451+02 | 2.5500002
(10 rows)

Load history collection is an enterprise feature and requires an enterprise license to use.

Configuration

Both the interval in which these metrics are collected and the number of measurements to retain can be configured.

Setting loadhistory.interval specifies the time between two measurements (in ms). The default value for this setting is 10000 (10 seconds). Setting this to 0 disables load history collection altogether.

Setting loadhistory.retention specifies the number of measurements that are stored before they will be dropped. The default value for this setting is 8640. For an interval of 10 seconds, this will retain values for 24 hours.

Metrics and Tables

All cedardb_*_load_history tables have as their first column the timestamp of when the measurement was taken.

CPU load

CedarDB makes available the CPU usage through the system table cedardb_cpu_load_history.

cpu_load: CPU usage in percent

Connection activity

CedarDB makes available metrics on connections through the system table cedardb_connection_load_history.

total: Total number of connections to the database open
active: Connections currently executing a statement
idle: Connections currently not inside a transaction
idle_in_transaction: Connections with an active transaction, but not currently executing a statement

Memory usage

Since CedarDB is optimized to make good use of memory, it uses 90% of system memory by default. Thus, it doesn’t report usage of system RAM, but rather the pressure on the buffer manager. This metric is exposed through the system table cedardb_memory_load_history.

buffer_pressure: The last known pressure estimate of the buffer manager

You can read more about CedarDB’s technology on the docs page.

Disk usage

CedarDB makes available metrics on the disk that the database resides on through the system table cedardb_disk_load_history.

All metrics are in bytes.

disk_size: The total size of the disk
free_space: The total free space left on the disk
db_file_size: The size of the db file
page_file_size: The size of the db.pages file
tmpfiles_dir_size: The combined size of all files inside the tmpfiles directory
wal_files_size: The combined size of all .wal files
read_bytes: The number of bytes read by CedarDB since startup
write_bytes: The number of bytes written by CedarDB since startup

Network I/O

CedarDB makes available metrics on network usage through the system table cedardb_network_load_history.

read_bytes: The total number of bytes read from any network interface (except loopback) since OS startup
write_bytes: The total number of bytes written to any network interface (except loopback) since OS startup

Tables on Google Cloud Storage Pgvector Extension