sql: DRY

sql/alter_table.go

@@ -119,8 +119,6 @@ func (p *planner) AlterTable(n *parser.AlterTable) (planNode, error) {
 	}
 
 	b.Put(MakeDescMetadataKey(tableDesc.GetID()), tableDesc)
-	// Mark transaction as operating on the system DB.
-	p.txn.SetSystemDBTrigger()
 
 	if err := p.txn.Run(&b); err != nil {
 		return nil, convertBatchError(tableDesc, b, err)

sql/create.go

@@ -91,8 +91,6 @@ func (p *planner) CreateIndex(n *parser.CreateIndex) (planNode, error) {
 	}
 
 	b.Put(MakeDescMetadataKey(tableDesc.GetID()), tableDesc)
-	// Mark transaction as operating on the system DB.
-	p.txn.SetSystemDBTrigger()
 
 	if err := p.txn.Run(&b); err != nil {
 		return nil, convertBatchError(tableDesc, b, err)

sql/descriptor.go

@@ -109,8 +109,7 @@ func (p *planner) createDescriptor(plainKey descriptorKey, descriptor descriptor
 	b := client.Batch{}
 	b.CPut(key, descriptor.GetID(), nil)
 	b.CPut(descKey, descriptor, nil)
-	// Mark transaction as operating on the system DB.
-	p.txn.SetSystemDBTrigger()
+
 	return p.txn.Run(&b)
 }
 

sql/drop.go

@@ -82,8 +82,7 @@ func (p *planner) DropDatabase(n *parser.DropDatabase) (planNode, error) {
 	b.Del(nameKey)
 	// Delete the zone config entry for this database.
 	b.Del(MakeZoneKey(desc.ID))
-	// Mark transaction as operating on the system DB.
-	p.txn.SetSystemDBTrigger()
+
 	if err := p.txn.Run(b); err != nil {
 		return nil, err
 	}
@@ -150,9 +149,6 @@ func (p *planner) DropIndex(n *parser.DropIndex) (planNode, error) {
 		if err := p.txn.Put(descKey, tableDesc); err != nil {
 			return nil, err
 		}
-
-		// Mark transaction as operating on the system DB.
-		p.txn.SetSystemDBTrigger()
 	}
 
 	if err := p.txn.Run(&b); err != nil {
@@ -218,8 +214,7 @@ func (p *planner) DropTable(n *parser.DropTable) (planNode, error) {
 		b.Del(nameKey)
 		// Delete the zone config entry for this table.
 		b.Del(MakeZoneKey(tableDesc.ID))
-		// Mark transaction as operating on the system DB.
-		p.txn.SetSystemDBTrigger()
+
 		if err := p.txn.Run(b); err != nil {
 			return nil, err
 		}

sql/grant.go

@@ -53,8 +53,6 @@ func (p *planner) Grant(n *parser.Grant) (planNode, error) {
 	// TODO(marc): do this inside a transaction. This will be needed
 	// when modifying multiple descriptors in the same op.
 	descKey := MakeDescMetadataKey(descriptor.GetID())
-	// Mark transaction as operating on the system DB.
-	p.txn.SetSystemDBTrigger()
 	if err := p.txn.Put(descKey, descriptor); err != nil {
 		return nil, err
 	}

sql/parser/stmt.go

@@ -92,7 +92,7 @@ func (*DropTable) StatementType() StatementType { return DDL }
 func (*Explain) StatementType() StatementType { return Rows }
 
 // StatementType implements the Statement interface.
-func (*Grant) StatementType() StatementType { return Ack }
+func (*Grant) StatementType() StatementType { return DDL }
 
 // StatementType implements the Statement interface.
 func (*Insert) StatementType() StatementType { return RowsAffected }
@@ -113,7 +113,7 @@ func (*RenameIndex) StatementType() StatementType { return DDL }
 func (*RenameTable) StatementType() StatementType { return DDL }
 
 // StatementType implements the Statement interface.
-func (*Revoke) StatementType() StatementType { return Ack }
+func (*Revoke) StatementType() StatementType { return DDL }
 
 // StatementType implements the Statement interface.
 func (*RollbackTransaction) StatementType() StatementType { return Ack }
@@ -146,7 +146,7 @@ func (*ShowIndex) StatementType() StatementType { return Rows }
 func (*ShowTables) StatementType() StatementType { return Rows }
 
 // StatementType implements the Statement interface.
-func (*Truncate) StatementType() StatementType { return DDL }
+func (*Truncate) StatementType() StatementType { return Ack }
 
 // StatementType implements the Statement interface.
 func (*Update) StatementType() StatementType { return RowsAffected }

sql/plan.go

@@ -49,6 +49,15 @@ func (p *planner) resetTxn() {
 // plan needs to be iterated over using planNode.Next() and planNode.Values()
 // in order to retrieve matching rows.
 func (p *planner) makePlan(stmt parser.Statement) (planNode, error) {
+	// This will set the system DB trigger for transactions containing
+	// DDL statements that have no effect, such as
+	// `BEGIN; INSERT INTO ...; CREATE TABLE IF NOT EXISTS ...; COMMIT;`
+	// where the table already exists. This will generate some false
+	// refreshes, but that's expected to be quite rare in practice.
+	if stmt.StatementType() == parser.DDL {
+		p.txn.SetSystemDBTrigger()
+	}
+
 	switch n := stmt.(type) {
 	case *parser.AlterTable:
 		return p.AlterTable(n)

sql/rename.go

@@ -70,8 +70,6 @@ func (p *planner) RenameDatabase(n *parser.RenameDatabase) (planNode, error) {
 	b.Put(descKey, dbDesc)
 	b.Del(databaseKey{string(n.Name)}.Key())
 
-	// Mark transaction as operating on the system DB.
-	p.txn.SetSystemDBTrigger()
 	if err := p.txn.Run(&b); err != nil {
 		if _, ok := err.(*proto.ConditionFailedError); ok {
 			return nil, fmt.Errorf("the new database name %q already exists", string(n.NewName))
@@ -158,8 +156,7 @@ func (p *planner) RenameTable(n *parser.RenameTable) (planNode, error) {
 	b.Put(descKey, tableDesc)
 	b.CPut(newTbKey, tableDesc.GetID(), nil)
 	b.Del(tbKey)
-	// Mark transaction as operating on the system DB.
-	p.txn.SetSystemDBTrigger()
+
 	if err := p.txn.Run(&b); err != nil {
 		if _, ok := err.(*proto.ConditionFailedError); ok {
 			return nil, fmt.Errorf("table name %q already exists", n.NewName.Table())
@@ -221,8 +218,6 @@ func (p *planner) RenameIndex(n *parser.RenameIndex) (planNode, error) {
 	if err := p.txn.Put(descKey, tableDesc); err != nil {
 		return nil, err
 	}
-	// Mark transaction as operating on the system DB.
-	p.txn.SetSystemDBTrigger()
 
 	return &valuesNode{}, nil
 }
@@ -302,8 +297,6 @@ func (p *planner) RenameColumn(n *parser.RenameColumn) (planNode, error) {
 	if err := p.txn.Put(descKey, tableDesc); err != nil {
 		return nil, err
 	}
-	// Mark transaction as operating on the system DB.
-	p.txn.SetSystemDBTrigger()
 
 	return &valuesNode{}, nil
 }

sql/revoke.go

@@ -53,8 +53,6 @@ func (p *planner) Revoke(n *parser.Revoke) (planNode, error) {
 	// TODO(marc): do this inside a transaction. This will be needed
 	// when modifying multiple descriptors in the same op.
 	descKey := MakeDescMetadataKey(descriptor.GetID())
-	// Mark transaction as operating on the system DB.
-	p.txn.SetSystemDBTrigger()
 	if err := p.txn.Put(descKey, descriptor); err != nil {
 		return nil, err
 	}