show_chunks()

Get the list of chunks associated with a hypertable.

Function accepts the following required and optional arguments. These arguments have the same semantics as the drop_chunks function.

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

  SELECT show_chunks('conditions');

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

  SELECT show_chunks('"MyMixedCaseTable"');

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• Or with schema qualification:

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

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

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

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

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

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• Get all chunks from the hypertable conditions created in the previous month:

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

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• Get all chunks from the hypertable conditions created before 2017:

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

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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 hypertable'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 chunk 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 hypertable's partitioning column. Otherwise the chunk 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 chunks between 3 and 4 months old. Similarly, specifying newer_than => '2017-01-01' and older_than => '2017-02-01' shows all chunks 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 monthsandcreated_before=> 3 months shows all chunks created between 3 and 4 months from now. Similarly, specifying created_after=> '2017-01-01'andcreated_before => '2017-02-01' shows all chunks 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.

Note

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