Gitlab Collector: User Indexes collector and test

collector/pg_stat_user_indexes.go

@@ -0,0 +1,141 @@
+// Copyright 2023 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package collector
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/go-kit/log"
+	"github.com/go-kit/log/level"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+func init() {
+	registerCollector(statUserIndexesSubsystem, defaultDisabled, NewPGStatUserIndexesCollector)
+}
+
+type PGStatUserIndexesCollector struct {
+	log log.Logger
+}
+
+const statUserIndexesSubsystem = "stat_user_indexes"
+
+func NewPGStatUserIndexesCollector(config collectorConfig) (Collector, error) {
+	return &PGStatUserIndexesCollector{log: config.logger}, nil
+}
+
+var (
+	statUserIndexesIdxScan = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, statUserIndexesSubsystem, "idx_scans_total"),
+		"Number of index scans initiated on this index",
+		[]string{"schemaname", "relname", "indexrelname"},
+		prometheus.Labels{},
+	)
+	statUserIndexesIdxTupRead = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, statUserIndexesSubsystem, "idx_tup_reads_total"),
+		"Number of index entries returned by scans on this index",
+		[]string{"schemaname", "relname", "indexrelname"},
+		prometheus.Labels{},
+	)
+	statUserIndexesIdxTupFetch = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, statUserIndexesSubsystem, "idx_tup_fetches_total"),
+		"Number of live table rows fetched by simple index scans using this index",
+		[]string{"schemaname", "relname", "indexrelname"},
+		prometheus.Labels{},
+	)
+
+	statUserIndexesQuery = `
+	SELECT
+		schemaname,
+		relname,
+		indexrelname,
+		idx_scan,
+		idx_tup_read,
+		idx_tup_fetch
+	FROM pg_stat_user_indexes
+	`
+)
+
+func (c *PGStatUserIndexesCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
+	db := instance.getDB()
+	rows, err := db.QueryContext(ctx,
+		statUserIndexesQuery)
+
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+	for rows.Next() {
+		var schemaname, relname, indexrelname sql.NullString
+		var idxScan, idxTupRead, idxTupFetch sql.NullFloat64
+
+		if err := rows.Scan(&schemaname, &relname, &indexrelname, &idxScan, &idxTupRead, &idxTupFetch); err != nil {
+			return err
+		}
+		if !schemaname.Valid {
+			level.Debug(c.log).Log("msg", "Skipping stats on index because schemaname is not valid")
+			continue
+		}
+		if !relname.Valid {
+			level.Debug(c.log).Log("msg", "Skipping stats on index because relname is not valid")
+			continue
+		}
+		if !indexrelname.Valid {
+			level.Debug(c.log).Log("msg", "Skipping stats on index because indexrelname is not valid")
+			continue
+		}
+		labels := []string{schemaname.String, relname.String, indexrelname.String}
+
+		if !idxScan.Valid {
+			level.Debug(c.log).Log("msg", "Skipping stats on index because idx_scan is not valid")
+			continue
+		}
+		if !idxTupRead.Valid {
+			level.Debug(c.log).Log("msg", "Skipping stats on index because idx_tup_read is not valid")
+			continue
+		}
+		if !idxTupFetch.Valid {
+			level.Debug(c.log).Log("msg", "Skipping stats on index because idx_tup_fetch is not valid")
+			continue
+		}
+
+		idxScanMetric := idxScan.Float64
+		ch <- prometheus.MustNewConstMetric(
+			statUserIndexesIdxScan,
+			prometheus.CounterValue,
+			idxScanMetric,
+			labels...,
+		)
+
+		idxTupReadMetric := idxTupRead.Float64
+		ch <- prometheus.MustNewConstMetric(
+			statUserIndexesIdxTupRead,
+			prometheus.CounterValue,
+			idxTupReadMetric,
+			labels...,
+		)
+
+		idxTupFetchMetric := idxTupFetch.Float64
+		ch <- prometheus.MustNewConstMetric(
+			statUserIndexesIdxTupFetch,
+			prometheus.CounterValue,
+			idxTupFetchMetric,
+			labels...,
+		)
+	}
+	if err := rows.Err(); err != nil {
+		return err
+	}
+	return nil
+}

collector/pg_stat_user_indexes_test.go

@@ -0,0 +1,68 @@
+// Copyright 2023 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package collector
+
+import (
+	"context"
+	"testing"
+
+	"github.com/DATA-DOG/go-sqlmock"
+	"github.com/prometheus/client_golang/prometheus"
+	dto "github.com/prometheus/client_model/go"
+	"github.com/smartystreets/goconvey/convey"
+)
+
+func TestPgStatUserIndexesCollector(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("Error opening a stub db connection: %s", err)
+	}
+	defer db.Close()
+	inst := &instance{db: db}
+	columns := []string{
+		"schemaname",
+		"relname",
+		"indexrelname",
+		"idx_scan",
+		"idx_tup_read",
+		"idx_tup_fetch",
+	}
+	rows := sqlmock.NewRows(columns).
+		AddRow("public", "pgbench_accounts", "pgbench_accounts_pkey", 5, 6, 7)
+
+	mock.ExpectQuery(sanitizeQuery(statUserIndexesQuery)).WillReturnRows(rows)
+
+	ch := make(chan prometheus.Metric)
+	go func() {
+		defer close(ch)
+		c := PGStatUserIndexesCollector{}
+
+		if err := c.Update(context.Background(), inst, ch); err != nil {
+			t.Errorf("Error calling PGStatUserIndexesCollector.Update: %s", err)
+		}
+	}()
+	expected := []MetricResult{
+		{labels: labelMap{"schemaname": "public", "relname": "pgbench_accounts", "indexrelname": "pgbench_accounts_pkey"}, value: 5, metricType: dto.MetricType_COUNTER},
+		{labels: labelMap{"schemaname": "public", "relname": "pgbench_accounts", "indexrelname": "pgbench_accounts_pkey"}, value: 6, metricType: dto.MetricType_COUNTER},
+		{labels: labelMap{"schemaname": "public", "relname": "pgbench_accounts", "indexrelname": "pgbench_accounts_pkey"}, value: 7, metricType: dto.MetricType_COUNTER},
+	}
+	convey.Convey("Metrics comparison", t, func() {
+		for _, expect := range expected {
+			m := readMetric(<-ch)
+			convey.So(expect, convey.ShouldResemble, m)
+		}
+	})
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("there were unfulfilled exceptions: %s", err)
+	}
+}