pgr_biconnectedComponents
— Return the biconnected components of an undirected graph.
In particular, the algorithm implemented by Boost.Graph.
Availability
n_seq
is removedSupport
The biconnected components of an undirected graph are the maximal subsets of vertices such that the removal of a vertex from particular component will not disconnect the component. Unlike connected components, vertices may belong to multiple biconnected components. Vertices can be present in multiple biconnected components, but each edge can only be contained in a single biconnected component.
The main characteristics are:
pgr_biconnectedComponents(Edges SQL)
RETURNS SET OF (seq, component, edge)
OR EMPTY SET
Example:  The biconnected components of the graph 

SELECT * FROM pgr_biconnectedComponents(
'SELECT id, source, target, cost, reverse_cost FROM edge_table'
);
seq  component  edge
++
1  1  1
2  2  2
3  2  3
4  2  4
5  2  5
6  2  8
7  2  9
8  2  10
9  2  11
10  2  12
11  2  13
12  2  15
13  2  16
14  6  6
15  7  7
16  14  14
17  17  17
18  18  18
(18 rows)
Parameter  Type  Default  Description 

Edges SQL  TEXT 
Inner query as described bellow. 
edges SQL:  an SQL query of an undirected graph, 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 
Returns set of (seq, component, edge)
Column  Type  Description 

seq  INT 
Sequential value starting from 1. 
component  BIGINT 
Component identifier. It is equal to the minimum edge identifier in the component. 
edge  BIGINT 
Identifier of the edge. 
Indices and tables