pgr_articulationPoints
 Return the articulation points of an undirected graph.
In particular, the algorithm implemented by Boost.Graph.
Warning
Experimental functions
Those vertices that belong to more than one biconnected component are called articulation points or, equivalently, cut vertices. Articulation points are vertices whose removal would increase the number of connected components in the graph. This implementation can only be used with an undirected graph.
The main Characteristics are:
 The returned values are ordered:
 node ascending
 Running time: \(O(V + E)\)
pgr_articulationPoints(edges_sql)
RETURNS SET OF (seq, node)
OR EMPTY SET
The signature is for a undirected graph.
Example: 

SELECT * FROM pgr_articulationPoints(
'SELECT id, source, target, cost, reverse_cost FROM edge_table'
);
seq  node
+
1  2
2  5
3  8
4  10
(4 rows)
edges_sql:  an SQL query, which should return a set of rows with the following columns: 

Column  Type  Default  Description 

id  ANYINTEGER 
Identifier of the edge.  
source  ANYINTEGER 
Identifier of the first end point vertex of the edge.  
target  ANYINTEGER 
Identifier of the second end point vertex of the edge.  
cost  ANYNUMERICAL 
Weight of the edge (source, target)


reverse_cost  ANYNUMERICAL 
1  Weight of the edge (target, source),

Where:
ANYINTEGER:  SMALLINT, INTEGER, BIGINT 

ANYNUMERICAL:  SMALLINT, INTEGER, BIGINT, REAL, FLOAT 
Parameter  Type  Default  Description 

edges_sql  TEXT 
SQL query as described above. 
Returns set of (seq, node)
Column  Type  Description 

seq  INT 
Sequential value starting from 1. 
node  BIGINT 
Identifier of the vertex. 
Indices and tables