approximate_row_count()

Since 0.10.0

Get approximate row count for hypertable, distributed hypertable, or regular PostgreSQL table based on catalog estimates. This function supports tables with nested inheritance and declarative partitioning.

The accuracy of approximate_row_count depends on the database having up-to-date statistics about the table or hypertable, which are updated by VACUUM, ANALYZE, and a few DDL commands. If you have auto-vacuum configured on your table or hypertable, or changes to the table are relatively infrequent, you might not need to explicitly ANALYZE your table as shown below. Otherwise, if your table statistics are too out-of-date, running this command updates your statistics and yields more accurate approximation results.

Samples

Get the approximate row count for a single hypertable.

ANALYZE conditions;

SELECT * FROM approximate_row_count('conditions');

The expected output:

approximate_row_count
---------------------
               240000

Arguments

The syntax is:

SELECT approximate_row_count('<table_name>');

Name	Type	Default	Required	Description
relation	REGCLASS	-	✔	hypertable or regular PostgreSQL table to get row count for.

Returns

Column	Type	Description
approximate_row_count	BIGINT	A numeric estimate of the number of rows in the specified table or hypertable.