Make FOR DISTRIBUTION optional when there is only one distribution

pkg/coord/adapter.go

@@ -37,10 +37,8 @@ func NewAdapter(conn *grpc.ClientConn) *Adapter {
 	}
 }
 
-
 // QDB returns the QDB object associated with the Adapter.
 
-//
 // Parameters:
 // - None.
 //
@@ -383,7 +381,7 @@ func (a *Adapter) DropKeyRange(ctx context.Context, krid string) error {
 //
 // Parameters:
 // - ctx (context.Context): The context for the request.
-// 
+//
 // Returns:
 // - error: An error if the key range drop fails, otherwise nil.
 func (a *Adapter) DropKeyRangeAll(ctx context.Context) error {
@@ -416,7 +414,7 @@ func (a *Adapter) RegisterRouter(ctx context.Context, r *topology.Router) error
 //
 // Parameters:
 // - ctx (context.Context): The context for the request.
-// 
+//
 // Returns:
 // - []*topology.Router: A list of router instances.
 // - error: An error if listing routers fails, otherwise nil.
@@ -768,7 +766,6 @@ func (a *Adapter) WriteTaskGroup(ctx context.Context, taskGroup *tasks.TaskGroup
 	return err
 }
 
-
 // RemoveTaskGroup removes a task group from the system.
 //
 // Parameters:

pkg/meta/meta.go

@@ -171,6 +171,9 @@ func processDrop(ctx context.Context, dstmt spqrparser.Statement, isCascade bool
 func processCreate(ctx context.Context, astmt spqrparser.Statement, mngr EntityMgr, cli *clientinteractor.PSQLInteractor) error {
 	switch stmt := astmt.(type) {
 	case *spqrparser.DistributionDefinition:
+		if stmt.ID == "default" {
+			return spqrerror.New(spqrerror.SPQR_INVALID_REQUEST, "You cannot create a \"default\" distribution, \"default\" is a reserved word")
+		}
 		distribution := distributions.NewDistribution(stmt.ID, stmt.ColTypes)
 
 		distributions, err := mngr.ListDistributions(ctx)
@@ -192,6 +195,19 @@ func processCreate(ctx context.Context, astmt spqrparser.Statement, mngr EntityM
 	case *spqrparser.ShardingRuleDefinition:
 		return cli.ReportError(spqrerror.ShardingRulesRemoved)
 	case *spqrparser.KeyRangeDefinition:
+		if stmt.Distribution == "default" {
+			list, err := mngr.ListDistributions(ctx)
+			if err != nil {
+				return spqrerror.New(spqrerror.SPQR_NO_DISTRIBUTION, "error while selecting list of distributions")
+			}
+			if len(list) == 0 {
+				return spqrerror.New(spqrerror.SPQR_NO_DISTRIBUTION, "you don't have any distributions")
+			}
+			if len(list) > 1 {
+				return spqrerror.New(spqrerror.SPQR_NO_DISTRIBUTION, "distributions count not equal one, use FOR DISTRIBUTION syntax")
+			}
+			stmt.Distribution = list[0].Id
+		}
 		ds, err := mngr.GetDistribution(ctx, stmt.Distribution)
 		if err != nil {
 			spqrlog.Zero.Error().Err(err).Msg("Error when adding key range")

test/regress/schedule/console

@@ -11,3 +11,4 @@ test: hash
 test: teardown
 test: delete_distribution
 test: sharding_rules
+test: default_distribution

test/regress/tests/console/expected/default_distribution.out

@@ -0,0 +1,61 @@
+
+		SPQR router admin console
+	Here you can configure your routing rules
+------------------------------------------------
+	You can find documentation here 
+https://github.com/pg-sharding/spqr/tree/master/docs
+
+CREATE KEY RANGE krid1 FROM 1 ROUTE TO sh1;
+ERROR:  you don't have any distributions.
+CREATE DISTRIBUTION ds1 COLUMN TYPES integer;
+    add distribution    
+------------------------
+ distribution id -> ds1
+(1 row)
+
+CREATE KEY RANGE krid1 FROM 1 ROUTE TO sh1;
+ add key range 
+---------------
+ bound -> 1
+(1 row)
+
+CREATE KEY RANGE krid2 FROM 11 ROUTE TO sh1;
+ add key range 
+---------------
+ bound -> 11
+(1 row)
+
+SHOW key_ranges;
+ Key range ID | Shard ID | Distribution ID | Lower bound 
+--------------+----------+-----------------+-------------
+ krid1        | sh1      | ds1             | 1
+ krid2        | sh1      | ds1             | 11
+(2 rows)
+
+CREATE DISTRIBUTION ds2 COLUMN TYPES integer;
+    add distribution    
+------------------------
+ distribution id -> ds2
+(1 row)
+
+CREATE KEY RANGE krid3 FROM 11 ROUTE TO sh2;
+ERROR:  distributions count not equal one, use FOR DISTRIBUTION syntax.
+SHOW key_ranges;
+ Key range ID | Shard ID | Distribution ID | Lower bound 
+--------------+----------+-----------------+-------------
+ krid1        | sh1      | ds1             | 1
+ krid2        | sh1      | ds1             | 11
+(2 rows)
+
+DROP DISTRIBUTION ALL CASCADE;
+   drop distribution    
+------------------------
+ distribution id -> ds1
+ distribution id -> ds2
+(2 rows)
+
+DROP KEY RANGE ALL;
+ drop key range 
+----------------
+(0 rows)
+

test/regress/tests/console/sql/default_distribution.sql

@@ -0,0 +1,15 @@
+CREATE KEY RANGE krid1 FROM 1 ROUTE TO sh1;
+CREATE DISTRIBUTION ds1 COLUMN TYPES integer;
+CREATE KEY RANGE krid1 FROM 1 ROUTE TO sh1;
+CREATE KEY RANGE krid2 FROM 11 ROUTE TO sh1;
+
+SHOW key_ranges;
+
+CREATE DISTRIBUTION ds2 COLUMN TYPES integer;
+CREATE KEY RANGE krid3 FROM 11 ROUTE TO sh2;
+
+SHOW key_ranges;
+
+
+DROP DISTRIBUTION ALL CASCADE;
+DROP KEY RANGE ALL;