feat: add pg_index_properties and pg_index_size_bytes

Signed-off-by: Michael Todorovic <[email protected]>

collector/pg_index.go

@@ -0,0 +1,170 @@
+// 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"
+	"fmt"
+	"strings"
+
+	"github.com/go-kit/log"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+func init() {
+	registerCollector(pgIndexSubsystem, defaultDisabled, NewPgIndexCollector)
+}
+
+type PGIndexCollector struct {
+	log log.Logger
+}
+
+const pgIndexSubsystem = "index"
+
+func NewPgIndexCollector(config collectorConfig) (Collector, error) {
+	return &PGIndexCollector{log: config.logger}, nil
+}
+
+var (
+	pgIndexProperties = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, pgIndexSubsystem, "properties"),
+		"Postgresql index properties",
+		[]string{"datname", "schemaname", "relname", "indexrelname", "is_unique", "is_primary", "is_valid", "is_ready"},
+		prometheus.Labels{},
+	)
+	pgIndexSize = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, pgIndexSubsystem, "size_bytes"),
+		"Postgresql index size in bytes",
+		[]string{"datname", "schemaname", "relname", "indexrelname"},
+		prometheus.Labels{},
+	)
+)
+
+func pgIndexQuery(columns []string) string {
+	return fmt.Sprintf("SELECT %s FROM pg_catalog.pg_stat_user_indexes s JOIN pg_catalog.pg_index i ON s.indexrelid = i.indexrelid WHERE i.indislive='1';", strings.Join(columns, ","))
+}
+
+func boolToString(b bool) string {
+	if b {
+		return "1"
+	}
+	return "0"
+}
+
+func (c *PGIndexCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
+	db := instance.getDB()
+
+	columns := []string{
+		"current_database() datname",
+		"s.schemaname",
+		"s.relname",
+		"s.indexrelname",
+		"i.indisunique",
+		"i.indisprimary",
+		"i.indisvalid",
+		"i.indisready",
+		"pg_relation_size(i.indexrelid) AS indexsize",
+	}
+
+	rows, err := db.QueryContext(ctx,
+		pgIndexQuery(columns),
+	)
+
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+	for rows.Next() {
+		var datname, schemaname, relname, indexrelname sql.NullString
+		var idxIsUnique, idxIsPrimary, idxIsValid, idxIsReady sql.NullBool
+		var idxSize sql.NullFloat64
+
+		r := []any{
+			&datname,
+			&schemaname,
+			&relname,
+			&indexrelname,
+			&idxIsUnique,
+			&idxIsPrimary,
+			&idxIsValid,
+			&idxIsReady,
+			&idxSize,
+		}
+
+		if err := rows.Scan(r...); err != nil {
+			return err
+		}
+		datnameLabel := "unknown"
+		if datname.Valid {
+			datnameLabel = datname.String
+		}
+		schemanameLabel := "unknown"
+		if schemaname.Valid {
+			schemanameLabel = schemaname.String
+		}
+		relnameLabel := "unknown"
+		if relname.Valid {
+			relnameLabel = relname.String
+		}
+		indexrelnameLabel := "unknown"
+		if indexrelname.Valid {
+			indexrelnameLabel = indexrelname.String
+		}
+
+		indexIsUniqueLabel := "unknown"
+		if idxIsUnique.Valid {
+			indexIsUniqueLabel = boolToString(idxIsUnique.Bool)
+		}
+
+		indexIsPrimaryLabel := "unknown"
+		if idxIsPrimary.Valid {
+			indexIsPrimaryLabel = boolToString(idxIsPrimary.Bool)
+		}
+
+		indexIsValidLabel := "unknown"
+		if idxIsValid.Valid {
+			indexIsValidLabel = boolToString(idxIsValid.Bool)
+		}
+
+		indexIsReadyLabel := "unknown"
+		if idxIsReady.Valid {
+			indexIsReadyLabel = boolToString(idxIsReady.Bool)
+		}
+
+		indexSizeMetric := -1.0
+		if idxSize.Valid {
+			indexSizeMetric = idxSize.Float64
+		}
+
+		propertiesLabels := []string{datnameLabel, schemanameLabel, relnameLabel, indexrelnameLabel, indexIsUniqueLabel, indexIsPrimaryLabel, indexIsValidLabel, indexIsReadyLabel}
+		ch <- prometheus.MustNewConstMetric(
+			pgIndexProperties,
+			prometheus.CounterValue,
+			1,
+			propertiesLabels...,
+		)
+
+		sizeLabels := []string{datnameLabel, schemanameLabel, relnameLabel, indexrelnameLabel}
+		ch <- prometheus.MustNewConstMetric(
+			pgIndexSize,
+			prometheus.GaugeValue,
+			indexSizeMetric,
+			sizeLabels...,
+		)
+	}
+	if err := rows.Err(); err != nil {
+		return err
+	}
+	return nil
+}

collector/pg_index_test.go

@@ -0,0 +1,84 @@
+// 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 TestPgIndexesCollector(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{
+		"datname",
+		"schemaname",
+		"relname",
+		"indexrelname",
+		"indisunique",
+		"indisprimary",
+		"indisvalid",
+		"indisready",
+		"indexsize",
+	}
+	rows := sqlmock.NewRows(columns).
+		AddRow("postgres", "public", "pgtest_accounts", "pgtest_accounts_pkey", "0", "1", "1", "1", "123456789")
+
+	cols := []string{
+		"current_database() datname",
+		"s.schemaname",
+		"s.relname",
+		"s.indexrelname",
+		"i.indisunique",
+		"i.indisprimary",
+		"i.indisvalid",
+		"i.indisready",
+		"pg_relation_size(i.indexrelid) AS indexsize",
+	}
+
+	mock.ExpectQuery(sanitizeQuery(pgIndexQuery(cols))).WillReturnRows(rows)
+
+	ch := make(chan prometheus.Metric)
+	go func() {
+		defer close(ch)
+		c := PGIndexCollector{}
+
+		if err := c.Update(context.Background(), inst, ch); err != nil {
+			t.Errorf("Error calling PGIndexCollector.Update: %s", err)
+		}
+	}()
+
+	expected := []MetricResult{
+		{labels: labelMap{"datname": "postgres", "indexrelname": "pgtest_accounts_pkey", "schemaname": "public", "relname": "pgtest_accounts", "is_unique": "0", "is_primary": "1", "is_valid": "1", "is_ready": "1"}, value: 1, metricType: dto.MetricType_COUNTER},
+		{labels: labelMap{"datname": "postgres", "indexrelname": "pgtest_accounts_pkey", "schemaname": "public", "relname": "pgtest_accounts"}, value: 123456789, metricType: dto.MetricType_GAUGE},
+	}
+	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)
+	}
+}