OPG_APIS.ESTIMATE_TRIANGLE

Format

COUNT_TRIANGLE_ESTIMATE(
   edge_tab_name IN VARCHAR2,
   wt_undBM      IN VARCHAR2,
   wt_rnmap      IN VARCHAR2,
   wt_undAM      IN VARCHAR2,
   num_sub_ptns  IN INTEGER DEFAULT 1,
   chunk_id      IN INTEGER DEFAULT 1,
   dop           IN INTEGER DEFAULT 1,
   tbs           IN VARCHAR2 DEFAULT NULL,
   options       IN VARCHAR2 DEFAULT NULL
   ) RETURN NUMBER;

Description

Estimates the number of triangles in a property graph.

Parameters

edge_tab_name

Name of the property graph edge table.

wt_undBM

A working table holding an undirected version of the original graph (before renumbering optimization).

wt_rnmap

A working table that is a mapping table for renumbering optimization.

wt_undAM

A working table holding the undirected version of the graph data after applying the renumbering optimization.

num_sub_ptns

Number of logical subpartitions used in calculating triangles . Must be a positive integer, power of 2 (1, 2, 4, 8, ...). For a graph with a relatively small maximum degree, use the value 1 (the default).

chunk_id

The logical subpartition to be used in triangle estimation (Only this partition will be counted). It must be an integer between 0 and num_sub_ptns*num_sub_ptns-1.

dop

Degree of parallelism for the operation. The default is 1 (no parallelism).

tbs

Name of the tablespace to hold the data stored in working tables.

options

Additional settings for operation. An optional string with one or more (comma-separated) of the following values:

PDML=T enables parallel DML.

Usage Notes

This function counts the total triangles in a portion of size 1/(num_sub_ptns*num_sub_ptns) of the graph; so to estimate the total number of triangles in the graph, you can multiply the result by num_sub_ptns*num_sub_ptns.

The property graph edge table must exist in the database, and the OPG_APIS.COUNT_TRIANGLE_PREP procedure must already have been executed.

Examples

The following example estimates the number of triangle in the property graph named connections. It does not perform the cleanup after it finishes, so you can count triangles again on the same graph without calling the preparation procedure.

set serveroutput on

DECLARE
  wt1 varchar2(100);  -- intermediate working table
  wt2 varchar2(100);
  wt3 varchar2(100);
  n number;
BEGIN
  opg_apis.count_triangle_prep('connectionsGE$', wt1, wt2, wt3);
  n := opg_apis.estimate_triangle_renum(
     'connectionsGE$',
      wt1,
      wt2,
      wt3,
      num_sub_ptns=>64,
      chunk_id=>2048,
      dop=>2,
      tbs => 'MYPG_TS',
      options=>'PDML=T'
      ); 
  dbms_output.put_line('estimated number of triangles ' || (n * 64 * 64));
END;
/