Questions tagged [performance]
An evaluation of whether a system works well enough to be fit for purpose. Normally performance refers to the speed with which a system completes an operation or set of operations over time.
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Under what circumstances will a memory optimized table variable with a hash index outperform other temporary tabular structures?
Context
Aside from victims of latch contention, everybody gave up on memory-optimized table variables pretty quickly. Probably around the time they realised that they still don't have statistics. Yet, ...
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Unexplained MYSQL memory allocation
I’m running MySQL server on Linux.
I have a long-standing issue on my database server — it keeps consuming an excessive amount of memory for no clear reason. As a result, I was forced to periodically ...
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Postgres Temp table performance
We are converting a database from SQL Server 2022 to Postgres 18.
Our system has a lot of code in the database and a lot of queries that use local temp tables a lot more than CTE's. This is due to the ...
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SQL Server 2022 CU11: Specific CPU Cores Constantly Spiking After Plan Cache Fills
We have observed an unusual CPU behavior on our SQL Server 2022 (Core Edition) starting from a specific date.
The issue is that a few specific CPU cores — particularly cores 1, 7, 14, and 21 — ...
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SQL Server process priority affects delete query performance
I have SQL Server running on my local machine. I write integration tests in c# and I need to clean up data after each test run. Only I have access to the server, and it does pretty much nothing ...
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Improved write performance after restarting Cassandra nodes
I have a 24-node cluster that receives 400k to 600k ops/s at a latency of approximately 15ms-20ms at the 99th percentile.
I haven't found the reason why after restarting the nodes, writes increase to ...
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On Sybase ASE 16, why is a simple query using a prepared statement 37 % slower than an equivalent stored procedure?
I am using Sybase Adaptive Server Enterprise (ASE) 16. I am using jConnect 4 in version 7.07.
I have a stored procedure that contains a rather simple query, equivalent to this one (I have changed the ...
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What happens in MariaDB if an index is dropped from a table while a join is running on that table?
I am running Fedora 42 KDE spin, and the output from mysql -V is
mysql Ver 15.1 Distrib 10.11.11-MariaDB, for Linux (x86_64) using
EditLine wrapper
I have a script that runs weekly that creates a ...
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Can I get data from an estimated Execution Plan in my C# code?
After years of growth, some reports now take minutes to extract from our database, and in some cases fail due to excess resource consumption. This depends on the parameters that our customers choose ...
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Can the NKTg Law analogy help in modeling database performance under variable data loads?
I recently came across the NKTg Law on Varying Inertia in physics, which describes an object’s movement tendency based on its position (x), velocity (v), and mass (m), with m allowed to change over ...
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Dynamically Adjusting max server memory Between Two Instances
I’ve got one server with two SQL instances. The server has 128 GB RAM.
Instance 1 has peak load from 08:00–10:00
Instance 2 has peak load from 14:00–17:00
Currently:
Instance 1 has max server ...
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Tracking stored procedure performance metrics
I’m trying to track impacts of stored procedure executions - CPU time, execution duration, logical/physical reads, memory grants, etc. - in order to visualize them. In particular, I'm looking for ...
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Do you know about a triple store that performs well under frequent CRUD operations?
I'm working with RDF data in real-world applications that require frequent create, update, and delete operations — classic CRUD behavior. However, I’ve noticed that many triple stores seem heavily ...
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MariaDB: Engine-independent statistics are not collected for column
In the course of optimizing my MariaDB database I have tried the following query (found in this blocg post):
ANALYZE TABLE <my_table> PERSISTENT FOR ALL;
The command runs without an error, ...
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Postgres query planner join selectivity greater than 1?
I am using PostgreSQL 14.17.
I am trying to debug a query planner failure in a bigger query, but I think I've narrowed down the
problem to a self-join on a join table:
SELECT t2.item_id
FROM ...
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