cozystack/packages/apps/postgres/tests/shared_buffers_test.yaml

suite: shared_buffers default follows the memory limit and request

# PostgreSQL's built-in shared_buffers default is 128MB regardless of the
# container. Below a 512Mi memory limit the chart defaults it to a quarter of
# the limit with a 16MB floor, capped at the memory request. From 512Mi up
# nothing is rendered, so those instances keep the PostgreSQL default.

templates:
  - templates/db.yaml

release:
  name: pg-test
  namespace: tenant-test

set:
  _cluster:
    scheduling: {}

tests:
  - it: "the default preset (t1.micro, 256Mi) gets 64MB"
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "64MB"

  - it: "t1.nano (128Mi) gets 32MB"
    set:
      resourcesPreset: t1.nano
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "32MB"

  - it: "a resources override that sets only cpu keeps the preset memory limit and its 32MB"
    set:
      resourcesPreset: t1.nano
      resources:
        cpu: 500m
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.resources.limits.memory
          value: 128Mi
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "32MB"

  - it: "explicit resources with 500Mi memory, just under the threshold, get 125MB"
    set:
      resources:
        cpu: 500m
        memory: 500Mi
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "125MB"

  - it: "a 32Mi limit is floored at 16MB"
    set:
      resources:
        cpu: 250m
        memory: 32Mi
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "16MB"

  - it: "t1.small (512Mi) renders no shared_buffers, as before"
    set:
      resourcesPreset: t1.small
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - notExists:
          path: spec.postgresql.parameters.shared_buffers

  - it: "t1.large (2Gi) renders no shared_buffers, as before"
    set:
      resourcesPreset: t1.large
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - notExists:
          path: spec.postgresql.parameters.shared_buffers

  - it: "an explicit shared_buffers wins over the default on a small preset"
    set:
      resourcesPreset: t1.nano
      postgresql:
        parameters:
          shared_buffers: "24MB"
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "24MB"

  - it: "an explicit shared_buffers is still rendered on a large preset"
    set:
      resourcesPreset: t1.large
      postgresql:
        parameters:
          shared_buffers: "1GB"
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "1GB"

  - it: "other default parameters are still rendered"
    set:
      resourcesPreset: t1.nano
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.postgresql.parameters.max_connections
          value: "100"
      - equal:
          path: spec.postgresql.parameters.max_wal_senders
          value: "30"

  - it: "the default preset caps shared_buffers below a fractional memory request"
    set:
      _cluster:
        memory-allocation-ratio: "5"
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.resources.requests.memory
          value: "53687091"
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "51MB"

  - it: "t1.nano caps shared_buffers at the memory request with overcommit"
    set:
      resourcesPreset: t1.nano
      _cluster:
        memory-allocation-ratio: "5"
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.resources.requests.memory
          value: "26843545"
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "25MB"

  - it: "a request equal to a quarter of the limit keeps the quarter"
    set:
      resourcesPreset: t1.nano
      _cluster:
        memory-allocation-ratio: "4"
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.resources.requests.memory
          value: "33554432"
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "32MB"

  - it: "a memory request below 16Mi takes precedence over the floor"
    set:
      resources:
        memory: 60Mi
      _cluster:
        memory-allocation-ratio: "4"
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.resources.requests.memory
          value: "15728640"
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "15MB"

  - it: "an explicit memory limit uses its rendered request for the cap"
    set:
      resources:
        memory: 500Mi
      _cluster:
        memory-allocation-ratio: "5"
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.resources.requests.memory
          value: "104857600"
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "100MB"

  - it: "an explicit shared_buffers still wins when memory is overcommitted"
    set:
      _cluster:
        memory-allocation-ratio: "5"
      postgresql:
        parameters:
          shared_buffers: "40MB"
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - equal:
          path: spec.postgresql.parameters.shared_buffers
          value: "40MB"

  - it: "512Mi still renders no default when memory is overcommitted"
    set:
      resourcesPreset: t1.small
      _cluster:
        memory-allocation-ratio: "5"
    documentSelector:
      path: kind
      value: Cluster
    asserts:
      - notExists:
          path: spec.postgresql.parameters.shared_buffers