On 2/16/25 23:55, 馬 騰飛 wrote:
Dear PostgreSQL Community,
I hope this message finds you well. I am reaching out to seek your technical
assistance regarding a performance issue we encountered after upgrading our
PostgreSQL version from 12.19 to 16.3.
We have noticed a significant performance problem with a specific SQL query on
one of our application screens.
Interestingly, when we isolate the problematic SQL statement and replace its
parameters with actual values, it executes in just a few seconds in pgAdmin.
However, when we run the same SQL query through our application using Npgsql,
it takes over ten minutes to complete.
We are using NpgsqlCommand.ExecuteReader to execute the SQL query, and the
parameters are set using NpgsqlCommand.Parameters.Add.
The main table involved in this query contains approximately 800,000 records.
We believe that the SQL statement itself does not have performance issues, but
there may be problems related to how the SQL is executed in the application or
how the parameters are set.
However, we are unable to pinpoint the exact cause of the performance
degradation.
Could you please provide us with some possible reasons or suggestions for
improvement? Your insights would be greatly appreciated.
This is going to need more information:
1) Was the upgrade done on the same machine or across machines?
If across machines how are they different?
2) The table definition.
3) The query text.
4) The Npgsql code.
Thank you for your assistance, and I look forward to your response.
Best regards,
Ma
--
Adrian Klaver
adrian.kla...@aklaver.com
