TimescaleDB API referenceContinuous aggregates

The CREATE MATERIALIZED VIEW statement is used to create continuous aggregates. To learn more, see the continuous aggregate how-to guides.

The syntax is:

CREATE MATERIALIZED VIEW <view_name> [ ( column_name [, ...] ) ]
WITH ( timescaledb.continuous [, timescaledb.<option> = <value> ] )
AS
<select_query>
[WITH [NO] DATA]

<select_query> is of the form:

SELECT <grouping_exprs>, <aggregate_functions>
FROM <hypertable or another continuous aggregate>
[WHERE ... ]
GROUP BY time_bucket( <const_value>, <partition_col_of_hypertable> ),
[ optional grouping exprs>]
[HAVING ...]

The continuous aggregate view defaults to WITH DATA. This means that when the view is created, it refreshes using all the current data in the underlying hypertable or continuous aggregate. This occurs once when the view is created. If you want the view to be refreshed regularly, you can use a refresh policy. If you do not want the view to update when it is first created, use the WITH NO DATA parameter. For more information, see refresh_continuous_aggregate.

Continuous aggregates have some limitations of what types of queries they can support. For more information, see the continuous aggregates section.

The settings for continuous aggregates are in the informational views.

NameTypeDescription
<view_name>TEXTName (optionally schema-qualified) of continuous aggregate view to create
<column_name>TEXTOptional list of names to be used for columns of the view. If not given, the column names are calculated from the query
WITH clauseTEXTSpecifies options for the continuous aggregate view
<select_query>TEXTA SELECT query that uses the specified syntax

Required WITH clause options:

NameTypeDescription
timescaledb.continuousBOOLEANIf timescaledb.continuous is not specified, this is a regular PostgresSQL materialized view

Optional WITH clause options:

NameTypeDescriptionDefault value
timescaledb.materialized_onlyBOOLEANReturn only materialized data when querying the continuous aggregate viewTRUE
timescaledb.create_group_indexesBOOLEANCreate indexes on the continuous aggregate for columns in its GROUP BY clause. Indexes are in the form (<GROUP_BY_COLUMN>, time_bucket)TRUE
timescaledb.finalizedBOOLEANIn TimescaleDB 2.7 and above, use the new version of continuous aggregates, which stores finalized results for aggregate functions. Supports all aggregate functions, including ones that use FILTER, ORDER BY, and DISTINCT clauses.TRUE

For more information, see the real-time aggregates section.

Create a daily continuous aggregate view:

CREATE MATERIALIZED VIEW continuous_aggregate_daily( timec, minl, sumt, sumh )
WITH (timescaledb.continuous) AS
SELECT time_bucket('1day', timec), min(location), sum(temperature), sum(humidity)
FROM conditions
GROUP BY time_bucket('1day', timec)

Add a thirty day continuous aggregate on top of the same raw hypertable:

CREATE MATERIALIZED VIEW continuous_aggregate_thirty_day( timec, minl, sumt, sumh )
WITH (timescaledb.continuous) AS
SELECT time_bucket('30day', timec), min(location), sum(temperature), sum(humidity)
FROM conditions
GROUP BY time_bucket('30day', timec);

Add an hourly continuous aggregate on top of the same raw hypertable:

CREATE MATERIALIZED VIEW continuous_aggregate_hourly( timec, minl, sumt, sumh )
WITH (timescaledb.continuous) AS
SELECT time_bucket('1h', timec), min(location), sum(temperature), sum(humidity)
FROM conditions
GROUP BY time_bucket('1h', timec);

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