Thread

1. Question on PostgreSQL Table Partitioning – Performance of Queries That Do Not Use the Partition Key

   atma ram <atmaramkp@gmail.com> — 2025-11-26T13:22:07Z

   Hi,
   
   Question on PostgreSQL Table Partitioning – Performance of Queries That Do
   Not Use the Partition Key
   
   We have a table that is approximately 1.6 GB in size. Query performance has
   started to degrade. Although we have multiple indexes, the large table size
   is still causing performance issues.
   
   We are planning to partition the table on the primary key. This is an OLTP
   system, and there are around 100 queries that access this table. About 80
   of these queries use the primary key and will therefore benefit directly
   from the partition key once we implement partitioning. However, the
   remaining 20 queries do not use the primary key; they rely on other indexed
   columns.
   
   Our question is: after partitioning the table, and after creating the
   necessary indexes on each partition, what happens to the performance of
   those 20 queries that do *not* use the partition key?
   – Will their performance degrade?
   – Will it remain the same as before partitioning?
   – Is there any chance it will improve?
   
   Additional details: we plan to create only 16 partitions, so the partition
   count will not be very high.
   
   *Is there any benchmarking, documentation, or reference material that can
   help demonstrate how partitioning will affect the performance of the 20
   queries that do not use the partition key?*
   
   This information is critical for us before proceeding with the partitioning
   strategy.
   
   Thank you in advance.
   
   Regards,
   Atma
   

2. Re: Question on PostgreSQL Table Partitioning – Performance of Queries That Do Not Use the Partition Key

   Aleksander Alekseev <aleksander@tigerdata.com> — 2025-11-26T13:49:49Z

   Hi Atma,
   
   > Question on PostgreSQL Table Partitioning – Performance of Queries That Do Not Use the Partition Key
   >
   > [...]
   
   pgsql-general@ might be a more appropriate mailing list for your
   question. Regarding the question per se, it would be helpful if you
   included the exact steps to reproduce the case.
   
   -- 
   Best regards,
   Aleksander Alekseev