Comments on: PostgreSQL partitioning (4): Hash partitioning https://www.dbi-services.com/blog/postgresql-partitioning-4-hash-partitioning/ Wed, 05 Mar 2025 06:14:21 +0000 hourly 1 By: Daniel Westermann https://www.dbi-services.com/blog/postgresql-partitioning-4-hash-partitioning/#comment-3768 Wed, 05 Mar 2025 06:14:21 +0000 https://www.dbi-services.com/blog/postgresql-partitioning-4-hash-partitioning/#comment-3768 In reply to Mike.

It is an internal function

]]> By: Mike https://www.dbi-services.com/blog/postgresql-partitioning-4-hash-partitioning/#comment-3767 Wed, 05 Mar 2025 04:46:29 +0000 https://www.dbi-services.com/blog/postgresql-partitioning-4-hash-partitioning/#comment-3767 Unless the hash function is an internal function and then the result of that goes through mod(5)… which makes the first demo of 1.4million records not going into partitions 3-5 very unlikely.

]]> By: Mike https://www.dbi-services.com/blog/postgresql-partitioning-4-hash-partitioning/#comment-3766 Wed, 05 Mar 2025 04:18:14 +0000 https://www.dbi-services.com/blog/postgresql-partitioning-4-hash-partitioning/#comment-3766 @Bob I’m confused.. with the hash function being “mod 5, remainder x”, hash(4) should be 4…

]]> By: Bob https://www.dbi-services.com/blog/postgresql-partitioning-4-hash-partitioning/#comment-1912 Mon, 20 Feb 2023 04:27:02 +0000 https://www.dbi-services.com/blog/postgresql-partitioning-4-hash-partitioning/#comment-1912 @Atul Because the hash() of 4 is not necessarily 4. In this case obviously hash(1), hash(4), and hash(5) are all equal to 1 in mod 5.

]]> By: Atul https://www.dbi-services.com/blog/postgresql-partitioning-4-hash-partitioning/#comment-95 Thu, 17 Nov 2022 06:52:37 +0000 https://www.dbi-services.com/blog/postgresql-partitioning-4-hash-partitioning/#comment-95 in your query insert into “traffic_violations_p_hash (councils) values (1),(2),(3),(4),(5)” I couldn’t understand how the data is distributed in the partitions after modulus calculation so could you help me in explaining in detail that why data 1,4,5 is gone in p1 partition anf why data 2,3 is gone p2 partition ?

please help me, i will be grateful to you.

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