From: | Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com> |
---|---|
To: | Ayush Vatsa <ayushvatsa1810(at)gmail(dot)com>, pgsql-general(at)lists(dot)postgresql(dot)org |
Subject: | Re: Query Discrepancy in Postgres HLL Test |
Date: | 2024-04-28 15:07:48 |
Message-ID: | a808a4b3-7f1d-4826-bc44-55565f0a99b9@aklaver.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
On 4/28/24 06:01, Ayush Vatsa wrote:
> Hi PostgreSQL Community,
> I'm currently delving into Postgres HLL (HyperLogLog) functionality and
> have encountered an unexpected behavior while executing queries from the
> "cumulative_add_sparse_edge.sql
> <https://github.com/citusdata/postgresql-hll/blob/master/sql/cumulative_add_sparse_edge.sql#L28-L36>" regress test. This particular test data file <https://github.com/citusdata/postgresql-hll/blob/master/sql/data/cumulative_add_sparse_edge.csv#L515-L516> involves three columns, with the last column representing an HLL (HyperLogLog) value derived from the previous HLL value and the current raw value.
>
> Upon manual inspection of the query responsible for deriving the last
> row's HLL value, I noticed a discrepancy. When executing the query:
> """
> -- '\x148B481002....' is second last rows hll value
> SELECT hll_add('\x148B481002.....', hll_hashval(2561));
> """
> instead of obtaining the expected value (''\x148B481002....''), I
> received a different output which is ('\x138b48000200410061008100a1
> ........').
>
> My initial assumption is that this could potentially be attributed to a
> precision error. However, I'm reaching out to seek clarity on why this
> disparity is occurring and to explore potential strategies for
> mitigating it (as I want the behaviour to be consistent to regress test
> file).
I would say your best option is to file an issue here:
https://github.com/citusdata/postgresql-hll/issues
>
> Regards
> Ayush Vatsa
--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com
From | Date | Subject | |
---|---|---|---|
Next Message | Cocam' server | 2024-04-29 13:45:31 | Need help to make space on my database |
Previous Message | Ayush Vatsa | 2024-04-28 13:01:05 | Query Discrepancy in Postgres HLL Test |