Distribution analysis overview

Functions for analyzing data distribution with histograms and approximate row counts

Distribution analysis functions help you understand how data is distributed across your datasets and perform fast approximate row counting on large tables.

Samples

Histogram distribution

Create a histogram showing the distribution of battery levels across devices:

SELECT device_id, histogram(battery_level, 20, 60, 5)
FROM readings
GROUP BY device_id
LIMIT 10;

The histogram partitions values into buckets between 20 and 60, with 5 equal-width buckets. The result includes an underflow bucket (values < 20) and an overflow bucket (values >= 60).

Approximate row count

Get a fast approximate count of rows in a hypertable without a full table scan:

ANALYZE conditions;

SELECT * FROM approximate_row_count('conditions');

This uses database statistics to provide a quick estimate, which is particularly useful for very large tables where exact counts would be expensive.

Available functions