{
  "uid": "scrabble-resources",
  "title": "Scrabble — Resources",
  "tags": ["scrabble"],
  "timezone": "",
  "schemaVersion": 39,
  "version": 2,
  "refresh": "30s",
  "time": { "from": "now-1h", "to": "now" },
  "panels": [
    {
      "type": "stat",
      "title": "Postgres connections",
      "description": "Backends connected to the scrabble database (postgres_exporter).",
      "gridPos": { "h": 5, "w": 6, "x": 0, "y": 0 },
      "datasource": { "type": "prometheus", "uid": "prometheus" },
      "targets": [{ "refId": "A", "expr": "sum(pg_stat_database_numbackends{datname=\"scrabble\"})" }]
    },
    {
      "type": "stat",
      "title": "Postgres cache hit ratio",
      "description": "blks_hit / (blks_hit + blks_read) over 5m.",
      "gridPos": { "h": 5, "w": 6, "x": 6, "y": 0 },
      "fieldConfig": { "defaults": { "unit": "percentunit", "min": 0, "max": 1 }, "overrides": [] },
      "datasource": { "type": "prometheus", "uid": "prometheus" },
      "targets": [{ "refId": "A", "expr": "sum(rate(pg_stat_database_blks_hit{datname=\"scrabble\"}[5m])) / clamp_min(sum(rate(pg_stat_database_blks_hit{datname=\"scrabble\"}[5m])) + sum(rate(pg_stat_database_blks_read{datname=\"scrabble\"}[5m])), 1)" }]
    },
    {
      "type": "stat",
      "title": "Postgres commits/s",
      "gridPos": { "h": 5, "w": 6, "x": 12, "y": 0 },
      "datasource": { "type": "prometheus", "uid": "prometheus" },
      "targets": [{ "refId": "A", "expr": "sum(rate(pg_stat_database_xact_commit{datname=\"scrabble\"}[5m]))" }]
    },
    {
      "type": "stat",
      "title": "Database size",
      "gridPos": { "h": 5, "w": 6, "x": 18, "y": 0 },
      "fieldConfig": { "defaults": { "unit": "bytes" }, "overrides": [] },
      "datasource": { "type": "prometheus", "uid": "prometheus" },
      "targets": [{ "refId": "A", "expr": "max(pg_database_size_bytes{datname=\"scrabble\"})" }]
    },
    {
      "type": "timeseries",
      "title": "Container CPU (cores) by container",
      "description": "docker_stats container.cpu.utilization (a gauge where 100 == one core) / 100, per scrabble-* container; the load harness appears when run as --name scrabble-loadtest. Verify the scaling against live Prometheus.",
      "gridPos": { "h": 8, "w": 12, "x": 0, "y": 5 },
      "datasource": { "type": "prometheus", "uid": "prometheus" },
      "targets": [{ "refId": "A", "expr": "max(container_cpu_utilization{container_name=~\"scrabble-.+\"}) by (container_name) / 100", "legendFormat": "{{container_name}}" }]
    },
    {
      "type": "timeseries",
      "title": "Container memory (usage) by container",
      "description": "docker_stats container.memory.usage.total bytes, per scrabble-* container.",
      "gridPos": { "h": 8, "w": 12, "x": 12, "y": 5 },
      "fieldConfig": { "defaults": { "unit": "bytes" }, "overrides": [] },
      "datasource": { "type": "prometheus", "uid": "prometheus" },
      "targets": [{ "refId": "A", "expr": "max(container_memory_usage_total{container_name=~\"scrabble-.+\"}) by (container_name)", "legendFormat": "{{container_name}}" }]
    },
    {
      "type": "timeseries",
      "title": "Container network I/O by container",
      "description": "docker_stats receive (+) and transmit (-) byte rates per scrabble-* container (summed across interfaces).",
      "gridPos": { "h": 8, "w": 12, "x": 0, "y": 13 },
      "fieldConfig": { "defaults": { "unit": "Bps" }, "overrides": [] },
      "datasource": { "type": "prometheus", "uid": "prometheus" },
      "targets": [
        { "refId": "A", "expr": "sum(rate(container_network_io_usage_rx_bytes{container_name=~\"scrabble-.+\"}[5m])) by (container_name)", "legendFormat": "rx {{container_name}}" },
        { "refId": "B", "expr": "-sum(rate(container_network_io_usage_tx_bytes{container_name=~\"scrabble-.+\"}[5m])) by (container_name)", "legendFormat": "tx {{container_name}}" }
      ]
    },
    {
      "type": "timeseries",
      "title": "Postgres transactions/s",
      "description": "Commit and rollback rates on the scrabble database (postgres_exporter).",
      "gridPos": { "h": 8, "w": 12, "x": 12, "y": 13 },
      "datasource": { "type": "prometheus", "uid": "prometheus" },
      "targets": [
        { "refId": "A", "expr": "sum(rate(pg_stat_database_xact_commit{datname=\"scrabble\"}[5m]))", "legendFormat": "commit" },
        { "refId": "B", "expr": "sum(rate(pg_stat_database_xact_rollback{datname=\"scrabble\"}[5m]))", "legendFormat": "rollback" }
      ]
    }
  ]
}
