CLUSTERING_INFORMATION

Returns clustering information of a table.

Syntax

CLUSTERING_INFORMATION('<database_name>', '<table_name>')

Examples

CREATE TABLE mytable(a int, b int) CLUSTER BY(a+1);

INSERT INTO mytable VALUES(1,1),(3,3);
INSERT INTO mytable VALUES(2,2),(5,5);
INSERT INTO mytable VALUES(4,4);

SELECT * FROM CLUSTERING_INFORMATION('default','mytable')\G
*************************** 1. row ***************************
            cluster_key: ((a + 1))
      total_block_count: 3
   constant_block_count: 1
unclustered_block_count: 0
       average_overlaps: 1.3333
          average_depth: 2.0
  block_depth_histogram: {"00002":3}

Parameter	Description
cluster_key	The defined cluster key.
total_block_count	The current count of blocks.
constant_block_count	The count of blocks where min/max values are equal, meaning each block contains only one (group of) cluster_key value.
unclustered_block_count	The count of blocks that have not yet been clustered.
average_overlaps	The average ratio of overlapping blocks within a given range.
average_depth	The average depth of overlapping partitions for the cluster key.
block_depth_histogram	The number of partitions at each depth level. A higher concentration of partitions at lower depths indicates more effective table clustering.