Start Vertex can be a variable

Author: JoshInnis

postgraph--0.1.0.sql

@@ -314,7 +314,7 @@ CREATE FUNCTION build_vertex(graphid, oid, gtype)
 RETURNS vertex 
 LANGUAGE c 
 IMMUTABLE 
-RETURNS NULL ON NULL INPUT 
+CALLED ON NULL INPUT 
 PARALLEL SAFE 
 COST 50
 AS 'MODULE_PATHNAME';

regress/expected/cypher_create.out

@@ -135,6 +135,14 @@ MATCH () RETURN 1;
  1
 (3 rows)
 
+MATCH (a) RETURN a;
+                              a                               
+--------------------------------------------------------------
+ {"id": 281474976710657, "label": "", "properties": {}}
+ {"id": 1125899906842625, "label": "test", "properties": {}}
+ {"id": 1688849860263937, "label": "test2", "properties": {}}
+(3 rows)
+
 CREATE ()-[]->();
 WARNING:  relcache reference leak: relation "_ag_label_vertex" not closed
 WARNING:  relcache reference leak: relation "_ag_label_vertex" not closed
@@ -156,14 +164,14 @@ EXPLAIN MATCH ()-[]->() RETURN 1;
 EXPLAIN ANALYZE MATCH ()-[]->() RETURN 1;
                                                                   QUERY PLAN                                                                   
 -----------------------------------------------------------------------------------------------------------------------------------------------
- Nested Loop  (cost=12.50..50471.30 rows=2520000 width=32) (actual time=0.060..0.237 rows=1 loops=1)
+ Nested Loop  (cost=12.50..50471.30 rows=2520000 width=32) (actual time=0.046..0.207 rows=1 loops=1)
    ->  Append  (cost=0.00..58.80 rows=2520 width=8) (actual time=0.005..0.013 rows=5 loops=1)
          ->  Seq Scan on _ag_label_vertex _age_default_alias_0_1  (cost=0.00..2.20 rows=120 width=8) (actual time=0.005..0.006 rows=3 loops=1)
          ->  Seq Scan on test _age_default_alias_0_2  (cost=0.00..22.00 rows=1200 width=8) (actual time=0.001..0.002 rows=1 loops=1)
          ->  Seq Scan on test2 _age_default_alias_0_3  (cost=0.00..22.00 rows=1200 width=8) (actual time=0.002..0.002 rows=1 loops=1)
-   ->  Function Scan on edge_search _age_default_alias_1  (cost=12.50..22.50 rows=1000 width=0) (actual time=0.043..0.043 rows=0 loops=5)
- Planning Time: 0.095 ms
- Execution Time: 0.262 ms
+   ->  Function Scan on edge_search _age_default_alias_1  (cost=12.50..22.50 rows=1000 width=0) (actual time=0.037..0.037 rows=0 loops=5)
+ Planning Time: 0.093 ms
+ Execution Time: 0.231 ms
 (8 rows)
 
 MATCH ()-[]->() RETURN 1;
@@ -185,13 +193,13 @@ SELECT * FROM cypher_create._ag_label_vertex;
 SELECT * FROM cypher_create._adj__adj__ag_label_vertex;
       id       | start_id | end_id | properties 
 ---------------+----------+--------+------------
- (0, 41914048) | (1, 2)   | (1, 3) | 
+ (0, 25304768) | (1, 2)   | (1, 3) | 
 (1 row)
 
 SELECT * FROM cypher_create._adj__ag_label_vertex;
       id       | start_id | end_id | properties 
 ---------------+----------+--------+------------
- (0, 41914048) | (1, 2)   | (1, 3) | 
+ (0, 25304768) | (1, 2)   | (1, 3) | 
 (1 row)
 
 MATCH () RETURN 1;

regress/sql/cypher_create.sql

@@ -44,6 +44,8 @@ SELECT * FROM cypher_create.test2;
 
 MATCH () RETURN 1;
 
+MATCH (a) RETURN a;
+
 CREATE ()-[]->();
 
 EXPLAIN MATCH ()-[]->() RETURN 1;

src/backend/parser/cypher_clause.c

@@ -1182,10 +1182,10 @@ static void transform_match_pattern(cypher_parsestate *cpstate, Query *query, Li
             if (i % 2 == 1) {
                 cypher_node *node = lfirst(path_cell);
                 prev_node = node;
+                bool has_variable = false;
+
                 if (node->name)
-                    ereport(ERROR,
-                            (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-                            errmsg("MATCH variable names are not supported")));
+                    has_variable = true;
                 else
                     node->name = get_next_default_alias(cpstate);
 
@@ -1260,11 +1260,17 @@ static void transform_match_pattern(cypher_parsestate *cpstate, Query *query, Li
 
                     //resno = pstate->p_next_resno++;
                     // XXX: End LTree Code here
+                    expr = (Expr *)make_vertex_expr(cpstate, pnsi);
+                    // make target entry and add it 
+                    resno = pstate->p_next_resno++;
+                    te = makeTargetEntry(expr, resno, node->name, false);
+
+                    query->targetList = lappend(query->targetList, te);
 
                   // 
                 } else {
 
-                    if (node->props) {
+                    if (node->props || has_variable) {
                     int sublevels_up =1;
                     Node * id_field = scanNSItemForColumn(cpstate, edge_pnsi, 0, "endid", -1);
 
@@ -1277,12 +1283,6 @@ static void transform_match_pattern(cypher_parsestate *cpstate, Query *query, Li
                     }
                     //edge_pnsi = pnsi;
                 } 
-                //expr = (Expr *)make_vertex_expr(cpstate, pnsi);
-                // make target entry and add it 
-                    //    pstate->p_next_resno++;
-                //te = makeTargetEntry(expr, resno, node->name, false);
-
-                //query->targetList = lappend(query->targetList, te);
 
                 // id field
                 Node *id = scanNSItemForColumn(pstate, pnsi, 0, AG_VERTEX_COLNAME_ID, -1);

src/backend/utils/adt/vertex.c

@@ -101,10 +101,13 @@ Datum
 build_vertex(PG_FUNCTION_ARGS) {
     graphid id = AG_GETARG_GRAPHID(0);
     Oid graph_oid = PG_GETARG_OID(1);
-    gtype *properties = AG_GET_ARG_GTYPE_P(2);
+    gtype *properties = NULL;
+    if (!PG_ARGISNULL(2)) {
+        properties = AG_GET_ARG_GTYPE_P(2);
 
-    if (!AGT_ROOT_IS_OBJECT(properties))
-        PG_RETURN_NULL();
+        if (!AGT_ROOT_IS_OBJECT(properties))
+            PG_RETURN_NULL();
+    }
 
     AG_RETURN_VERTEX(create_vertex(id, graph_oid, properties));
 }
@@ -124,6 +127,17 @@ create_vertex(graphid id, Oid graph_oid, gtype *properties) {
     append_to_buffer(&buffer, (char *)&graph_oid, sizeof(Oid));
 
     // properties
+    if (properties == NULL) {   
+        gtype_in_state result;
+        
+        memset(&result, 0, sizeof(gtype_in_state));
+                                            
+        push_gtype_value(&result.parse_state, WGT_BEGIN_OBJECT, NULL);
+        result.res = push_gtype_value(&result.parse_state, WGT_END_OBJECT, NULL); 
+                    
+        properties = gtype_value_to_gtype(result.res);
+    }    
+    
     append_to_buffer(&buffer, properties, VARSIZE(properties));
 
     vertex *v = (vertex *)buffer.data;