PMM-10974 Fallback to PGSS in case of not available PGSM.

agent/serviceinfobroker/service_info_broker.go

@@ -26,6 +26,7 @@ import (
 
 	"github.com/go-sql-driver/mysql"
 	"github.com/lib/pq"
+	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	"go.mongodb.org/mongo-driver/mongo"
 
@@ -231,6 +232,13 @@ func (sib *ServiceInfoBroker) getPostgreSQLInfo(ctx context.Context, dsn string,
 	}
 	res.Version = version
 
+	var pgsmVersion string
+	err = db.QueryRowContext(ctx, "SELECT /* agent='serviceinfobroker' */ extversion FROM pg_extension WHERE extname = 'pg_stat_monitor';").Scan(&pgsmVersion)
+	if err != nil && !errors.Is(err, sql.ErrNoRows) {
+		res.Error = err.Error()
+	}
+	res.PgsmVersion = pgsmVersion
+
 	return &res
 }
 

agent/serviceinfobroker/service_info_broker_test.go

@@ -249,6 +249,20 @@ func TestServiceInfoBroker(t *testing.T) {
 		assert.InDelta(t, 250, resp.TableCount, 150)
 	})
 
+	t.Run("PostgreSQLOptions", func(t *testing.T) {
+		cfgStorage := config.NewStorage(&config.Config{
+			Paths: config.Paths{TempDir: t.TempDir()},
+		})
+		c := New(cfgStorage)
+		resp := c.GetInfoFromService(context.Background(), &agentpb.ServiceInfoRequest{
+			Dsn:  tests.GetTestPostgreSQLDSN(t),
+			Type: inventorypb.ServiceType_POSTGRESQL_SERVICE,
+		}, 0)
+		require.NotNil(t, resp)
+		assert.Equal(t, []string{"postgres", "pmm-agent"}, resp.DatabaseList)
+		assert.Equal(t, "", resp.PgsmVersion)
+	})
+
 	t.Run("MongoDBWithSSL", func(t *testing.T) {
 		mongoDBDSNWithSSL, mongoDBTextFiles := tests.GetTestMongoDBWithSSLDSN(t, "../")
 

api/agentpb/agent.proto

@@ -474,6 +474,8 @@ message ServiceInfoResponse {
   string version = 3;
   // A list of PostgreSQL databases.
   repeated string database_list = 4;
+  // A version of pg_stat_monitor, empty if unavailable.
+  string pgsm_version = 5;
 }
 
 // JobStatusRequest is a ServerMessage asking pmm-agent for job status.

managed/models/agent_model.go

@@ -129,6 +129,7 @@
 	SSLKey             string `json:"ssl_key"`
 	AutoDiscoveryLimit int32  `json:"auto_discovery_limit"`
 	DatabaseCount      int32  `json:"database_count"`
+	PGSMVersion        string `json:"pgsm_version"`
 }
 
 // Value implements database/sql/driver.Valuer interface. Should be defined on the value.
@@ -439,7 +440,7 @@
 
 		if s.MongoDBOptions != nil {
 			if s.MongoDBOptions.TLSCertificateKey != "" {
 				q.Add("tlsCertificateKeyFile", tdp.Left+".TextFiles."+certificateKeyFilePlaceholder+tdp.Right)
 			}
 			if s.MongoDBOptions.TLSCertificateKeyFilePassword != "" {
 				q.Add("tlsCertificateKeyFilePassword", s.MongoDBOptions.TLSCertificateKeyFilePassword)

managed/services/agents/service_info_broker.go

@@ -211,6 +211,7 @@ func (c *ServiceInfoBroker) GetInfoFromService(ctx context.Context, q *reform.Qu
 				}
 			}
 		}
+		agent.PostgreSQLOptions.PGSMVersion = sInfo.PgsmVersion
 		agent.PostgreSQLOptions.DatabaseCount = int32(databaseCount - excludedDatabaseCount)
 
 		l.Debugf("Updating PostgreSQL options, database count: %d.", agent.PostgreSQLOptions.DatabaseCount)

managed/services/management/postgresql.go

@@ -19,6 +19,7 @@ import (
 	"context"
 
 	"github.com/AlekSi/pointer"
+	"github.com/sirupsen/logrus"
 	"gopkg.in/reform.v1"
 
 	"github.com/percona/pmm/api/inventorypb"
@@ -37,6 +38,7 @@ type PostgreSQLService struct {
 	state agentsStateUpdater
 	cc    connectionChecker
 	sib   serviceInfoBroker
+	l     *logrus.Entry
 }
 
 // NewPostgreSQLService creates new PostgreSQL Management Service.
@@ -46,6 +48,7 @@ func NewPostgreSQLService(db *reform.DB, state agentsStateUpdater, cc connection
 		state: state,
 		cc:    cc,
 		sib:   sib,
+		l:     logrus.WithField("component", "postgresql"),
 	}
 }
 
@@ -93,6 +96,7 @@ func (s *PostgreSQLService) Add(ctx context.Context, req *managementpb.AddPostgr
 			return err
 		}
 
+		options := models.PostgreSQLOptionsFromRequest(req)
 		row, err := models.CreateAgent(tx.Querier, models.PostgresExporterType, &models.CreateAgentParams{
 			PMMAgentID:        req.PmmAgentId,
 			ServiceID:         service.ServiceID,
@@ -104,7 +108,7 @@ func (s *PostgreSQLService) Add(ctx context.Context, req *managementpb.AddPostgr
 			PushMetrics:       isPushMode(req.MetricsMode),
 			ExposeExporter:    req.ExposeExporter,
 			DisableCollectors: req.DisableCollectors,
-			PostgreSQLOptions: models.PostgreSQLOptionsFromRequest(req),
+			PostgreSQLOptions: options,
 			LogLevel:          services.SpecifyLogLevel(req.LogLevel, inventorypb.LogLevel_error),
 		})
 		if err != nil {
@@ -119,6 +123,13 @@ func (s *PostgreSQLService) Add(ctx context.Context, req *managementpb.AddPostgr
 			if err = s.sib.GetInfoFromService(ctx, tx.Querier, service, row); err != nil {
 				return err
 			}
+
+			// In case of not available PGSM extension it is switch to PGSS.
+			if req.QanPostgresqlPgstatmonitorAgent && row.PostgreSQLOptions.PGSMVersion == "" {
+				s.l.Warningln("Extension pg_stat_monitor is not available. Switching to pg_stats_statements.")
+				req.QanPostgresqlPgstatementsAgent = true
+				req.QanPostgresqlPgstatmonitorAgent = false
+			}
 		}
 
 		agent, err := services.ToAPIAgent(tx.Querier, row)
@@ -138,7 +149,7 @@ func (s *PostgreSQLService) Add(ctx context.Context, req *managementpb.AddPostgr
 				CommentsParsingDisabled: req.DisableCommentsParsing,
 				TLS:                     req.Tls,
 				TLSSkipVerify:           req.TlsSkipVerify,
-				PostgreSQLOptions:       models.PostgreSQLOptionsFromRequest(req),
+				PostgreSQLOptions:       options,
 				LogLevel:                services.SpecifyLogLevel(req.LogLevel, inventorypb.LogLevel_fatal),
 			})
 			if err != nil {
@@ -163,7 +174,7 @@ func (s *PostgreSQLService) Add(ctx context.Context, req *managementpb.AddPostgr
 				CommentsParsingDisabled: req.DisableCommentsParsing,
 				TLS:                     req.Tls,
 				TLSSkipVerify:           req.TlsSkipVerify,
-				PostgreSQLOptions:       models.PostgreSQLOptionsFromRequest(req),
+				PostgreSQLOptions:       options,
 				LogLevel:                services.SpecifyLogLevel(req.LogLevel, inventorypb.LogLevel_fatal),
 			})
 			if err != nil {