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.
6,487 questions
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SQL Server replication is in "Performance critical" status persistently
I have multiple publication in the sql server with
SQL Server version: 2017
Transactional REplication
Distributor and Publisher are in the same server
Subscriber is on the different server
Also:
9 ...
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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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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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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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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 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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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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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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SLEEP_TASK waits on single-threaded UPDATE that does not generate an in-flight plan, how are these waits possible?
Yesterday, I witnesses a running query in sp_WhoIsActive that I could not explain. It had the following properties:
It ran in a nested transaction. The first transaction bulk inserts into a temp ...
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What are better approaches than loops for frequent operations?
I have to make multiple UPDATE statements, but I'm looking for the best approach to do so, in terms of readability and performance. I looked for another answers but the only thing I found is that &...
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MySQL 8.0.41 - 83 % Waiting for row lock on AO_319474_QUEUE
Environment
We run three Jira Service Management DC clusters that all share the same topology:
MySQL 8.0.36 on Ubuntu 22.04 – 32 vCPU, 100 GB RAM, buffer-pool now 80 GB (only ~33 GB in use), NVMe ...
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MariaDB 4-5 times slower than Oracle
since Oracle will increase the costs for running databases my employer is currently evaluating alternatives for oracle databases.
In one application we currently use oracle db with no specific ...
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MYSQL and random performance of store procedure
I run this SP at night, when there’s almost no activity. The SP performs an accumulative calculation of machine usage from a laundromat—an artisanal BI query. It writes the result to a table.
On most ...
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Unexplained read latency in SQL Server despite healthy RAID 10 disk and good synthetic benchmarks
I've set up a SQL Server instance on a dedicated Windows server. The .mdf data file is placed on a dedicated disk configured as RAID 10, with the RAID controller cache ratio set to 90% write / 10% ...
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Resource allocation strategy for Cassandra on a single server
I have a single physical server running Cassandra. Given that Cassandra performs poorly with fat nodes, which strategy is better:
Running a single large node on the server (allocating all resources ...
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Querying system tables runs very slow on some servers
I have a SQL Server 2019 Enterprise and Quest LiteSpeed for SQL Server installed on all servers. On some of the servers the connection from LiteSpeed to SQL Server in GUI times out. After talking to ...
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How can I make queries on a dynamic part of my data fast?
The Problem
I have a query that will always only hit the data from the past two weeks. It is business critical, so it must be fast. The table is inserted into very many times per hour. The table is ...
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Performant way to perform update over 300M records in MYSQL
Context
I have an entity called 'Interaction'.
interaction | CREATE TABLE `interaction` (
`id` varchar(36) NOT NULL,
`entity_id` varchar(36) DEFAULT NULL,
`request_date` datetime DEFAULT NULL,
...
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Does the query execution planner in mysql v8 recognize that x=1 and x in(1) are the same
I have the following 2 queries:
SELECT * FROM mytable
WHERE id=1;
and
SELECT * FROM mytable
WHERE id IN(1);
Assuming that mytable is very large, I am interested in the performance difference for the ...
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Make LIKE 'abc%' query faster?
Will a hash index make this query faster?
LIKE 'abc%'
Hash indices can speed up point queries.
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Performance improvements for read only SQL Db that is only ever restored from backup
I receive a .bak file from a 3rd party on a monthly basis and create 1 db each receipt.
.bak file size is ~1Gb.
This data is for lookup only and I never write to it. Are there any steps I can take to ...
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Is there a performance benefit to having a partitioning column not be the first key of an index?
If you are well read on partitioning, then you will be completely aware that partitioning is not a performance feature for rowstore indexes. However, whenever I see arguments made for this, as most ...
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Efficient way to update comment like statuses after user login in a React application
I’m building a blog application in React where each blog displays a list of comments. Each comment includes:
Like count (total number of likes for the comment)
Like status (whether the currently ...
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How to reduce running time? Execution time exceeded
Excuse my grammar Im dyslexic:
The main issue is that after calculating all the lags and flows at the ISIN level, when I try to do the final grouping by bucket, asset class, and date, I'm forced to re-...
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Why am I getting an INDEX SKIP SCAN?
Scenario is as follows:
Table T is created as of
CREATE TABLE T
(
f_a ...
,f_b ...
,f_c ...
,ctv NUMBER(*,0) NOT NULL
,ffc DATE NOT NULL
,v NUMBER(1,0)
,uc NUMBER(1,...
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