hyper table dimensions

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1

Hi, can someone please give me an unambiguous explanation of dimensions?
I have scoured the internet for a meaningful explanation with no success.
EG:
CREATE TABLE public.raw_data_dimen5 (
rt_timestamp timestamptz NOT NULL,
rt_entityid uuid NOT NULL,
rt_value float8 NULL,
rt_quality int4 NULL
)

CREATE UNIQUE INDEX idx_deviceid_time25 ON raw_data_dimen5(rt_entityid,rt_timestamp);

SELECT create_hypertable(‘raw_data_dimen5’, ‘rt_timestamp’);
SELECT add_dimension(‘raw_data_dimen5’, ‘rt_entityid’, number_partitions => 20);

Then data inserted.

This creates 20 “dependencies”, my question is how is the data structured within these dependencies/partitions/dimensions?
Also how does one estimate “number_partitions =>”? I guess with a clearer understanding of how dimensions are structured, then the question may become irrelevant?

Any help much appreciated.

2

Hi Craig, dimensions are like flat information that is not compacted. They work like a “key” for grouping sets of values of the same kind.

They can be really fast for finding groups of values and then values are also grouped in batches. Check more here.

Probably this entire content from the previous link can help you to better understand the architecture of the compressed data.

3

Thanks for the response, albeit my question was not answered. Luckily I got all the concise and accurate answers from ChatGPT.
Regards

4

Very good to know that you got your answer @craig.

Feel free to share your learnings on the topic, more people can benefit from it in the future.

5

ChatGPT was able to answer your question? That’s amazing!