alter publications if needed

pkg/cluster/database.go

@@ -39,7 +39,12 @@ const (
 	createExtensionSQL      = `CREATE EXTENSION IF NOT EXISTS "%s" SCHEMA "%s"`
 	alterExtensionSQL       = `ALTER EXTENSION "%s" SET SCHEMA "%s"`
 
+	getPublicationsSQL = `SELECT p.pubname, string_agg(pt.schemaname || . || pt.tablename, ', ' ORDER BY pt.schemaname, pt.tablename)
+	        FROM pg_publication p
+			JOIN pg_publication_tables pt ON pt.pubname = p.pubname
+			GROUP BY p.pubname;`
 	createPublicationSQL = `CREATE PUBLICATION "%s" FOR TABLE %s WITH (publish = 'insert, update');`
+	alterPublicationSQL  = `ALTER PUBLICATION "%s" SET TABLE %s;`
 
 	globalDefaultPrivilegesSQL = `SET ROLE TO "%s";
 			ALTER DEFAULT PRIVILEGES GRANT USAGE ON SCHEMAS TO "%s","%s";
@@ -508,6 +513,67 @@ func (c *Cluster) execCreateOrAlterExtension(extName, schemaName, statement, doi
 	return nil
 }
 
+// getPublications returns the list of current database publications with tables
+// The caller is responsible for opening and closing the database connection
+func (c *Cluster) getPublications() (publications map[string]string, err error) {
+	var (
+		rows           *sql.Rows
+		dbPublications map[string]string
+	)
+
+	if rows, err = c.pgDb.Query(getPublicationsSQL); err != nil {
+		return nil, fmt.Errorf("could not query database publications: %v", err)
+	}
+
+	defer func() {
+		if err2 := rows.Close(); err2 != nil {
+			if err != nil {
+				err = fmt.Errorf("error when closing query cursor: %v, previous error: %v", err2, err)
+			} else {
+				err = fmt.Errorf("error when closing query cursor: %v", err2)
+			}
+		}
+	}()
+
+	for rows.Next() {
+		var (
+			dbPublication       string
+			dbPublicationTables string
+		)
+
+		if err = rows.Scan(&dbPublication, &dbPublicationTables); err != nil {
+			return nil, fmt.Errorf("error when processing row: %v", err)
+		}
+		dbPublications[dbPublication] = dbPublicationTables
+	}
+
+	return dbPublications, err
+}
+
+// executeCreatePublication creates new publication for given tables
+// The caller is responsible for opening and closing the database connection.
+func (c *Cluster) executeCreatePublication(pubName, tableList string) error {
+	return c.execCreateOrAlterPublication(pubName, tableList, createPublicationSQL,
+		"creating publication", "create publication")
+}
+
+// executeAlterExtension changes the table list of the given publication.
+// The caller is responsible for opening and closing the database connection.
+func (c *Cluster) executeAlterPublication(pubName, tableList string) error {
+	return c.execCreateOrAlterPublication(pubName, tableList, alterPublicationSQL,
+		"changing table list of publication", "alter publication tables")
+}
+
+func (c *Cluster) execCreateOrAlterPublication(pubName, tableList, statement, doing, operation string) error {
+
+	c.logger.Infof("%s %q table list %q", doing, pubName, tableList)
+	if _, err := c.pgDb.Exec(fmt.Sprintf(statement, pubName, tableList)); err != nil {
+		return fmt.Errorf("could not execute %s: %v", operation, err)
+	}
+
+	return nil
+}
+
 // Creates a connection pool credentials lookup function in every database to
 // perform remote authentication.
 func (c *Cluster) installLookupFunction(poolerSchema, poolerUser string) error {
@@ -612,23 +678,3 @@ func (c *Cluster) installLookupFunction(poolerSchema, poolerUser string) error {
 
 	return nil
 }
-
-// getExtension returns the list of current database extensions
-// The caller is responsible for opening and closing the database connection
-func (c *Cluster) createPublication(dbName, publication, tables string) (err error) {
-
-	if err := c.initDbConnWithName(dbName); err != nil {
-		return fmt.Errorf("could not init connection to database %q", dbName)
-	}
-	defer func() {
-		if err = c.closeDbConn(); err != nil {
-			err = fmt.Errorf("could not close connection to database %q: %v", dbName, err)
-		}
-	}()
-
-	if _, err := c.pgDb.Exec(fmt.Sprintf(createPublicationSQL, publication, tables)); err != nil {
-		return fmt.Errorf("could not create publication %s: %v", publication, err)
-	}
-
-	return err
-}

pkg/cluster/streams.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"reflect"
+	"sort"
 	"strings"
 
 	acidv1 "github.com/zalando/postgres-operator/pkg/apis/acid.zalan.do/v1"
@@ -77,6 +78,15 @@ func (c *Cluster) syncPostgresConfig() error {
 
 	slots := make(map[string]map[string]string)
 	publications := make(map[string]map[string]acidv1.StreamTable)
+	createPublications := make(map[string]string)
+	alterPublications := make(map[string]string)
+
+	defer func() {
+		if err := c.closeDbConn(); err != nil {
+			c.logger.Errorf("could not close database connection: %v", err)
+		}
+	}()
+
 	desiredPatroniConfig := c.Spec.Patroni
 	if len(desiredPatroniConfig.Slots) > 0 {
 		slots = desiredPatroniConfig.Slots
@@ -135,9 +145,19 @@ func (c *Cluster) syncPostgresConfig() error {
 		}
 	}
 
-	// next create publications to each created slot
+	// next, create publications to each created slot
 	for publication, tables := range publications {
+		// but first check for existing publications
 		dbName := slots[publication]["database"]
+		if err := c.initDbConnWithName(dbName); err != nil {
+			return fmt.Errorf("could not init database connection")
+		}
+
+		currentPublications, err := c.getPublications()
+		if err != nil {
+			return fmt.Errorf("could not get current publications: %v", err)
+		}
+
 		tableNames := make([]string, len(tables))
 		i := 0
 		for t := range tables {
@@ -145,12 +165,31 @@ func (c *Cluster) syncPostgresConfig() error {
 			tableNames[i] = fmt.Sprintf("%q.%q", schemaName, tableName)
 			i++
 		}
+		sort.Strings(tableNames)
 		tableList := strings.Join(tableNames, ", ")
-		c.logger.Debugf("creating publication %q in database %q for tables %s", publication, dbName, tableList)
-		if err := c.createPublication(dbName, publication, tableList); err != nil {
+
+		currentTables, exists := currentPublications[publication]
+		if !exists {
+			createPublications[publication] = tableList
+		} else if currentTables != tableList {
+			alterPublications[publication] = tableList
+		}
+
+		if len(createPublications)+len(alterPublications) == 0 {
+			return nil
+		}
+
+		for publicationName, tables := range createPublications {
+			if err = c.executeCreatePublication(publicationName, tables); err != nil {
 				c.logger.Warningf("%v", err)
 			}
 		}
+		for publicationName, tables := range alterPublications {
+			if err = c.executeAlterPublication(publicationName, tables); err != nil {
+				c.logger.Warningf("%v", err)
+			}
+		}
+	}
 
 	return nil
 }