pgr_bdDijkstra — Returns the shortest path(s) using Bidirectional Dijkstra algorithm.
Availability:
pgr_dijkstra(edges_sql, start_vid, end_vid)
pgr_bdDijkstra(edges_sql, start_vid, end_vid, directed)
RETURNS SET OF (seq, path_seq, node, edge, cost, agg_cost)
OR EMPTY SET
pgr_bdDijkstra(edges_sql, start_vid, end_vid)
RETURNS SET OF (seq, path_seq, node, edge, cost, agg_cost) or EMPTY SET
The minimal signature is for a directed graph from one start_vid to one end_vid:
Example: 

SELECT * FROM pgr_bdDijkstra(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
2, 3
);
seq  path_seq  node  edge  cost  agg_cost
+++++
1  1  2  4  1  0
2  2  5  8  1  1
3  3  6  9  1  2
4  4  9  16  1  3
5  5  4  3  1  4
6  6  3  1  0  5
(6 rows)
pgr_bdDijkstra(edges_sql, start_vid, end_vid, directed)
RETURNS SET OF (seq, path_seq, node, edge, cost, agg_cost) or EMPTY SET
Example: 

SELECT * FROM pgr_bdDijkstra(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
2, 3,
false
);
seq  path_seq  node  edge  cost  agg_cost
+++++
1  1  2  2  1  0
2  2  3  1  0  1
(2 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 
Column  Type  Default  Description 

sql  TEXT  SQL query as described above.  
start_vid  BIGINT  Identifier of the starting vertex of the path.  
start_vids  ARRAY[BIGINT]  Array of identifiers of starting vertices.  
end_vid  BIGINT  Identifier of the ending vertex of the path.  
end_vids  ARRAY[BIGINT]  Array of identifiers of ending vertices.  
directed  BOOLEAN  true 

Returns set of (seq, path_seq [, start_vid] [, end_vid], node, edge, cost, agg_cost)
Column  Type  Description 

seq  INT  Sequential value starting from 1. 
path_id  INT  Path identifier. Has value 1 for the first of a path. Used when there are multiple paths for the same start_vid to end_vid combination. 
path_seq  INT  Relative position in the path. Has value 1 for the beginning of a path. 
start_vid  BIGINT  Identifier of the starting vertex. Used when multiple starting vetrices are in the query. 
end_vid  BIGINT  Identifier of the ending vertex. Used when multiple ending vertices are in the query. 
node  BIGINT  Identifier of the node in the path from start_vid to end_vid. 
edge  BIGINT  Identifier of the edge used to go from node to the next node in the path sequence. 1 for the last node of the path. 
cost  FLOAT  Cost to traverse from node using edge to the next node in the path sequence. 
agg_cost  FLOAT  Aggregate cost from start_v to node. 
Indices and tables