hypertable_columnstore_stats()

Get columnstore statistics related to the columnstore

Since 2.18.0

hypertable_columnstore_stats() replaces hypertable_compression_stats(), deprecated in 2.18.0. The parameters are the same.

Retrieve compression statistics for the .

For more information about using s, including size partitioning, see s.

Samples

To retrieve compression statistics:

• Show the compression status of the conditions :

  SELECT * FROM hypertable_columnstore_stats('conditions');
  

  Returns:

  -[ RECORD 1 ]------------------+------
  total_chunks                   | 4
  number_compressed_chunks       | 1
  before_compression_table_bytes | 8192
  before_compression_index_bytes | 32768
  before_compression_toast_bytes | 0
  before_compression_total_bytes | 40960
  after_compression_table_bytes  | 8192
  after_compression_index_bytes  | 32768
  after_compression_toast_bytes  | 8192
  after_compression_total_bytes  | 49152
  node_name                      |
  

• Use pg_size_pretty get the output in a more human friendly format:

  SELECT pg_size_pretty(after_compression_total_bytes) as total
    FROM hypertable_columnstore_stats('conditions');
  

  Returns:

  -[ RECORD 1 ]--+------
  total | 48 kB
  

Arguments

The syntax is:

SELECT * FROM hypertable_columnstore_stats('<hypertable_name>');

Name	Type	Description
hypertable	REGCLASS	to show statistics for

Returns

Column	Type	Description
total_chunks	BIGINT	The number of s used by the . Returns NULL if compression_status == Uncompressed.
number_compressed_chunks	BIGINT	The number of s used by the that are currently compressed. Returns NULL if compression_status == Uncompressed.
before_compression_table_bytes	BIGINT	Size of the heap before compression. Returns NULL if compression_status == Uncompressed.
before_compression_index_bytes	BIGINT	Size of all the indexes before compression. Returns NULL if compression_status == Uncompressed.
before_compression_toast_bytes	BIGINT	Size the TOAST table before compression. Returns NULL if compression_status == Uncompressed.
before_compression_total_bytes	BIGINT	Size of the entire table (before_compression_table_bytes + before_compression_index_bytes + before_compression_toast_bytes) before compression. Returns NULL if compression_status == Uncompressed.
after_compression_table_bytes	BIGINT	Size of the heap after compression. Returns NULL if compression_status == Uncompressed.
after_compression_index_bytes	BIGINT	Size of all the indexes after compression. Returns NULL if compression_status == Uncompressed.
after_compression_toast_bytes	BIGINT	Size the TOAST table after compression. Returns NULL if compression_status == Uncompressed.
after_compression_total_bytes	BIGINT	Size of the entire table (after_compression_table_bytes + after_compression_index_bytes + after_compression_toast_bytes) after compression. Returns NULL if compression_status == Uncompressed.
node_name	NAME	nodes on which the is located, applicable only to distributed s. Returns NULL if compression_status == Uncompressed.