Performance and testing

vmk8s

This page summarizes the configuration parameters and testing methods that can help optimize and validate Charmed PostgreSQL deployments. It provides operational guidelines for adjusting resource allocation profiles, applying hardware constraints, and executing functional validation tests.

Resource allocation

Charmed PostgreSQL resource allocation can be controlled via the charm’s profile config option:

juju config postgresql profile=<production|testing>

juju config postgresql-k8s profile=<production|testing>

Hardware constraints

The Juju --constraints flag sets RAM and CPU limits for Juju units :

juju deploy postgresql --channel 14/stable --constraints cores=8 mem=16G

juju deploy postgresql --channel 14/stable --constraints cores=8 mem=16G --trust

Juju constraints can be set together with the charm’s profile:

juju deploy postgresql --channel 14/stable --constraints cores=8 mem=16G --config profile=testing

juju deploy postgresql-k8s --channel 14/stable --constraints cores=8 mem=16G --config profile=testing --trust

Testing your deployment

Benchmarking

For performance testing and benchmarking charms, we recommend using the Charmed Sysbench operator. This is a tool for benchmarking database applications that includes monitoring and CPU/RAM/IO performance measurement.

Smoke test

This type of test ensures that basic functionality works over a short amount of time.

One way to do this is by integrating your PostgreSQL application with the PostgreSQL Test Application , and running the “continuous writes” test:

juju run postgresql-test-app/leader start-continuous-writes
Juju 2.9 users

Remember that juju run <action name> becomes juju run-action <action name> --wait for Juju 2.9.

The expected behaviour is:

  • postgresql-test-app will continuously insert records into the database received through the integration (the table continuous_writes).

  • The counters (amount of records in table) will grow on all cluster members

juju add-model smoke-test

juju deploy postgresql --channel 14/stable
juju add-unit postgresql -n 2

juju deploy postgresql-test-app
juju integrate postgresql-test-app:database postgresql

# Optionally configure write speed (default is 500 miliseconds)
juju config postgresql-test-app sleep_interval=1000

juju run postgresql-test-app/leader start-continuous-writes

juju run postgresql-test-app/leader show-continuous-writes

juju add-model smoke-test

juju deploy postgresql-k8s --channel 14/stable --trust
juju scale-application postgresql-k8s 3

juju deploy postgresql-test-app
juju integrate postgresql-test-app:database postgresql

# Optionally configure write speed (default is 500 miliseconds)
juju config postgresql-test-app sleep_interval=1000

juju run postgresql-test-app/leader start-continuous-writes

juju run postgresql-test-app/leader show-continuous-writes
Juju 2.9 users

Remember that juju integrate becomes juju relate for Juju 2.9.

To stop the “continuous write” test, run

juju run postgresql-test-app/leader stop-continuous-writes

To truncate the “continuous write” table (i.e. delete all records from database), run

juju run postgresql-test-app/leader clear-continuous-writes

Watch the data being written:

export user=operator
export pass=$(juju run postgresql/leader get-password username=${user} | yq '.. | select(. | has("password")).password')
export relname=first-database
export ip=$(juju show-unit postgresql/0 --endpoint database | yq '.. | select(. | has("public-address")).public-address')
export db=$(juju show-unit postgresql/0 --endpoint database | yq '.. | select(. | has("database")).database')
export relid=$(juju show-unit postgresql/0 --endpoint database | yq '.. | select(. | has("relation-id")).relation-id')
export query="select count(*) from continuous_writes"

watch -n1 -x juju run postgresql-test-app/leader run-sql dbname=${db} query="${query}" relation-id=${relid} relation-name=${relname}

# OR

watch -n1 -x juju ssh --container postgresql postgresql/leader "psql postgresql://${user}:${pass}@${ip}:5432/${db} -c \"${query}\""

export user=operator
export pass=$(juju run postgresql-k8s/leader get-password username=${user} | yq '.. | select(. | has("password")).password')
export relname=first-database
export ip=$(juju show-unit postgresql-k8s/0 --endpoint database | yq '.. | select(. | has("public-address")).public-address')
export db=$(juju show-unit postgresql-k8s/0 --endpoint database | yq '.. | select(. | has("database")).database')
export relid=$(juju show-unit postgresql-k8s/0 --endpoint database | yq '.. | select(. | has("relation-id")).relation-id')
export query="select count(*) from continuous_writes"

watch -n1 -x juju run postgresql-test-app/leader run-sql dbname=${db} query="${query}" relation-id=${relid} relation-name=${relname}

# OR

watch -n1 -x juju ssh --container postgresql postgresql-k8s/leader "psql postgresql://${user}:${pass}@${ip}:5432/${db} -c \"${query}\""

System test

To perform a system test, deploy the PostgreSQL charm bundle (VM | K8s ). This charm bundle automatically deploys and tests all the necessary parts at once.