show_chunks()

show the chunks belonging to a hypertable

Since 0.9.0

Samples

• Get the list of all s associated with a table:

  SELECT show_chunks('conditions');
  

• For s with mixed-case names, include double quotes within the string literal:

  SELECT show_chunks('"MyMixedCaseTable"');
  

• Or with schema qualification:

  SELECT show_chunks('public."MyMixedCaseTable"');
  

• Get all s from the called conditions that are older than 3 months:

  SELECT show_chunks('conditions', older_than => INTERVAL '3 months');
  

• Get all s from the called conditions created earlier than 3 months before:

  SELECT show_chunks('conditions', created_before => INTERVAL '3 months');
  

• Get all s from the conditions created in the previous month:

  SELECT show_chunks('conditions', created_after => INTERVAL '1 month');
  

• Get all s from the conditions created before 2017:

  SELECT show_chunks('conditions', older_than => DATE '2017-01-01');
  

Arguments

The syntax is:

SELECT show_chunks(
    relation = '<hypertable_or_cagg_name>',
    older_than = <interval>,
    newer_than = <interval>,
    created_before = <interval>,
    created_after = <interval>
);

Name	Type	Default	Required	Description
relation	REGCLASS	-	✔	or from which to select s.
older_than	ANY	-	✖	Specification of cut-off point where any s older than this timestamp should be shown.
newer_than	ANY	-	✖	Specification of cut-off point where any s newer than this timestamp should be shown.
created_before	ANY	-	✖	Specification of cut-off point where any s created before this timestamp should be shown.
created_after	ANY	-	✖	Specification of cut-off point where any s created after this timestamp should be shown.

The older_than and newer_than parameters can be specified in two ways:

• interval type: The cut-off point is computed as now() - older_than and similarly now() - newer_than. An error is returned if an INTERVAL is supplied and the time column is not one of a TIMESTAMP, TIMESTAMPTZ, or DATE.

• timestamp, date, or integer type: The cut-off point is explicitly given as a TIMESTAMP / TIMESTAMPTZ / DATE or as a SMALLINT / INT / BIGINT. The choice of timestamp or integer must follow the type of the ‘s time column.

The created_before and created_after parameters can be specified in two ways:

• interval type: The cut-off point is computed as now() - created_before and similarly now() - created_after. This uses the creation time for the filtering.

• timestamp, date, or integer type: The cut-off point is explicitly given as a TIMESTAMP / TIMESTAMPTZ / DATE or as a SMALLINT / INT / BIGINT. The choice of integer value must follow the type of the ‘s partitioning column. Otherwise the creation time is used for the filtering.

When both older_than and newer_than arguments are used, the function returns the intersection of the resulting two ranges. For example, specifying newer_than => 4 months and older_than => 3 months shows all s between 3 and 4 months old. Similarly, specifying newer_than => '2017-01-01' and older_than => '2017-02-01' shows all s between ‘2017-01-01’ and ‘2017-02-01’. Specifying parameters that do not result in an overlapping intersection between two ranges results in an error.

When both created_before and created_after arguments are used, the function returns the intersection of the resulting two ranges. For example, specifying created_after => 4 months and created_before => 3 months shows all s created between 3 and 4 months from now. Similarly, specifying created_after => '2017-01-01' and created_before => '2017-02-01' shows all s created between ‘2017-01-01’ and ‘2017-02-01’. Specifying parameters that do not result in an overlapping intersection between two ranges results in an error.

The created_before/created_after parameters cannot be used together with older_than/newer_than.

Returns

Column	Type	Description
show_chunks	REGCLASS	Name of the matching the criteria

This function returns a set of rows, one for each that matches the specified criteria.

On failure, an error is returned:

Error	Description
invalid hypertable or continuous aggregate	The specified relation is not a valid or
invalid time range	The specified time range parameters do not result in a valid overlapping range