Add "--generate-explain-analyze-helper-sql" command

Like "--generate-stats-helper-sql" this allows generating a SQL script
that installs the pganalyze.explain_analyze helper into all databases on
a server, as specified by the server section name passed as an argument.

Additionally, the "--generate-helper-explain-analyze-role" option allows
setting the role that the helper function should be owned by as a value,
defaulting to "pganalyze_explain".

Note that the role creation, as well as any GRANT statements for the role
must be taken care of separately.

main.go

@@ -50,6 +50,8 @@ func main() {
 	var testExplain bool
 	var testSection string
 	var generateStatsHelperSql string
+	var generateHelperExplainAnalyzeSql string
+	var generateHelperExplainAnalyzeRole string
 	var forceStateUpdate bool
 	var configFilename string
 	var stateFilename string
@@ -74,6 +76,8 @@ func main() {
 	flag.BoolVar(&testExplain, "test-explain", false, "Tests whether EXPLAIN collection works by issuing a dummy query (ensure log collection works first)")
 	flag.StringVar(&testSection, "test-section", "", "Tests a particular section of the config file, i.e. a specific server, and ignores all other config sections")
 	flag.StringVar(&generateStatsHelperSql, "generate-stats-helper-sql", "", "Generates a SQL script for the given server (name of section in the config file, or \"default\" for env variables), that can be run with \"psql -f\" for installing the collector stats helpers on all configured databases")
+	flag.StringVar(&generateHelperExplainAnalyzeSql, "generate-explain-analyze-helper-sql", "", "Generates a SQL script for the given server (name of section in the config file, or \"default\" for env variables), that can be run with \"psql -f\" for installing the collector pganalyze.explain_analyze helper on all configured databases")
+	flag.StringVar(&generateHelperExplainAnalyzeRole, "generate-explain-analyze-helper-role", "pganalyze_explain", "Sets owner role of the pganalyze.explain_analyze helper function, defaults to \"pganalyze_explain\"")
 	flag.BoolVar(&reloadRun, "reload", false, "Reloads the collector daemon that's running on the host")
 	flag.BoolVar(&noReload, "no-reload", false, "Disables automatic config reloading during a test run")
 	flag.BoolVarP(&logger.Verbose, "verbose", "v", false, "Outputs additional debugging information, use this if you're encountering errors or other problems")
@@ -145,33 +149,35 @@ func main() {
 		}
 	}
 
-	if testRunLogs || testRunAndTrace || testExplain || generateStatsHelperSql != "" {
+	if testRunLogs || testRunAndTrace || testExplain || generateStatsHelperSql != "" || generateHelperExplainAnalyzeSql != "" {
 		testRun = true
 	}
 
 	globalCollectionOpts := state.CollectionOpts{
-		StartedAt:                time.Now(),
-		SubmitCollectedData:      !benchmark && true,
-		TestRun:                  testRun,
-		TestRunLogs:              testRunLogs || dryRunLogs,
-		TestExplain:              testExplain,
-		TestSection:              testSection,
-		GenerateStatsHelperSql:   generateStatsHelperSql,
-		DebugLogs:                debugLogs,
-		DiscoverLogLocation:      discoverLogLocation,
-		CollectPostgresRelations: !noPostgresRelations,
-		CollectPostgresSettings:  !noPostgresSettings,
-		CollectPostgresLocks:     !noPostgresLocks,
-		CollectPostgresFunctions: !noPostgresFunctions,
-		CollectPostgresBloat:     !noPostgresBloat,
-		CollectPostgresViews:     !noPostgresViews,
-		CollectLogs:              !noLogs,
-		CollectExplain:           !noExplain,
-		CollectSystemInformation: !noSystemInformation,
-		StateFilename:            stateFilename,
-		WriteStateUpdate:         (!dryRun && !dryRunLogs && !testRun) || forceStateUpdate,
-		ForceEmptyGrant:          dryRun || dryRunLogs || testRunLogs || benchmark,
-		OutputAsJson:             !benchmark,
+		StartedAt:                        time.Now(),
+		SubmitCollectedData:              !benchmark && true,
+		TestRun:                          testRun,
+		TestRunLogs:                      testRunLogs || dryRunLogs,
+		TestExplain:                      testExplain,
+		TestSection:                      testSection,
+		GenerateStatsHelperSql:           generateStatsHelperSql,
+		GenerateHelperExplainAnalyzeSql:  generateHelperExplainAnalyzeSql,
+		GenerateHelperExplainAnalyzeRole: generateHelperExplainAnalyzeRole,
+		DebugLogs:                        debugLogs,
+		DiscoverLogLocation:              discoverLogLocation,
+		CollectPostgresRelations:         !noPostgresRelations,
+		CollectPostgresSettings:          !noPostgresSettings,
+		CollectPostgresLocks:             !noPostgresLocks,
+		CollectPostgresFunctions:         !noPostgresFunctions,
+		CollectPostgresBloat:             !noPostgresBloat,
+		CollectPostgresViews:             !noPostgresViews,
+		CollectLogs:                      !noLogs,
+		CollectExplain:                   !noExplain,
+		CollectSystemInformation:         !noSystemInformation,
+		StateFilename:                    stateFilename,
+		WriteStateUpdate:                 (!dryRun && !dryRunLogs && !testRun) || forceStateUpdate,
+		ForceEmptyGrant:                  dryRun || dryRunLogs || testRunLogs || benchmark,
+		OutputAsJson:                     !benchmark,
 	}
 
 	if reloadRun && !testRun {

runner/generate_helper_sql.go

@@ -68,3 +68,36 @@ func GenerateStatsHelperSql(ctx context.Context, server *state.Server, globalCol
 
 	return output.String(), nil
 }
+
+func GenerateExplainAnalyzeHelperSql(ctx context.Context, server *state.Server, globalCollectionOpts state.CollectionOpts, logger *util.Logger) (string, error) {
+	db, err := postgres.EstablishConnection(ctx, server, logger, globalCollectionOpts, "")
+	if err != nil {
+		return "", err
+	}
+	defer db.Close()
+
+	version, err := postgres.GetPostgresVersion(ctx, logger, db)
+	if err != nil {
+		return "", fmt.Errorf("error collecting Postgres version: %s", err)
+	}
+
+	databases, _, err := postgres.GetDatabases(ctx, logger, db, version)
+	if err != nil {
+		return "", fmt.Errorf("error collecting pg_databases: %s", err)
+	}
+
+	output := strings.Builder{}
+	for _, dbName := range postgres.GetDatabasesToCollect(server, databases) {
+		output.WriteString(fmt.Sprintf("\\c %s\n", pq.QuoteIdentifier(dbName)))
+		output.WriteString("CREATE SCHEMA IF NOT EXISTS pganalyze;\n")
+		output.WriteString(fmt.Sprintf("GRANT USAGE ON SCHEMA pganalyze TO %s;\n", server.Config.GetDbUsername()))
+		output.WriteString(fmt.Sprintf("GRANT CREATE ON SCHEMA pganalyze TO %s;\n", globalCollectionOpts.GenerateExplainAnalyzeHelperRole))
+		output.WriteString(fmt.Sprintf("SET ROLE %s;\n", globalCollectionOpts.GenerateExplainAnalyzeHelperRole))
+		output.WriteString(util.ExplainAnalyzeHelper + "\n")
+		output.WriteString("RESET ROLE;\n")
+		output.WriteString(fmt.Sprintf("REVOKE CREATE ON SCHEMA pganalyze FROM %s;\n", globalCollectionOpts.GenerateExplainAnalyzeHelperRole))
+		output.WriteString("\n")
+	}
+
+	return output.String(), nil
+}

runner/run.go

@@ -130,6 +130,34 @@ func Run(ctx context.Context, wg *sync.WaitGroup, globalCollectionOpts state.Col
 		return
 	}
 
+	if globalCollectionOpts.GenerateExplainAnalyzeHelperSql != "" {
+		wg.Add(1)
+		testRunSuccess = make(chan bool)
+		go func() {
+			var matchingServer *state.Server
+			for _, server := range servers {
+				if globalCollectionOpts.GenerateExplainAnalyzeHelperSql == server.Config.SectionName {
+					matchingServer = server
+				}
+			}
+			if matchingServer == nil {
+				fmt.Fprintf(os.Stderr, "ERROR - Specified configuration section name '%s' not known\n", globalCollectionOpts.GenerateExplainAnalyzeHelperSql)
+				testRunSuccess <- false
+			} else {
+				output, err := GenerateExplainAnalyzeHelperSql(ctx, matchingServer, globalCollectionOpts, logger.WithPrefix(matchingServer.Config.SectionName))
+				if err != nil {
+					fmt.Fprintf(os.Stderr, "ERROR - %s\n", err)
+					testRunSuccess <- false
+				} else {
+					fmt.Print(output)
+					testRunSuccess <- true
+				}
+			}
+			wg.Done()
+		}()
+		return
+	}
+
 	state.ReadStateFile(servers, globalCollectionOpts, logger)
 
 	writeStateFile = func() {

state/state.go

@@ -213,14 +213,16 @@ type CollectionOpts struct {
 
 	DiffStatements bool
 
-	SubmitCollectedData    bool
-	TestRun                bool
-	TestRunLogs            bool
-	TestExplain            bool
-	TestSection            string
-	GenerateStatsHelperSql string
-	DebugLogs              bool
-	DiscoverLogLocation    bool
+	SubmitCollectedData              bool
+	TestRun                          bool
+	TestRunLogs                      bool
+	TestExplain                      bool
+	TestSection                      string
+	GenerateStatsHelperSql           string
+	GenerateExplainAnalyzeHelperSql  string
+	GenerateExplainAnalyzeHelperRole string
+	DebugLogs                        bool
+	DiscoverLogLocation              bool
 
 	StateFilename    string
 	WriteStateUpdate bool