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.

learn more… | top users | synonyms

1
vote
0answers
18 views

Question about MySQL triggers performance

I currently have a database that stores some transactions for several users, for example purchasing or selling products is stored as 1 entry in the transactions table. It can also store profits made ...
2
votes
1answer
32 views

Database design - summary table vs always counting over tables

Imagine a system where a user can make a whole lot of different actions, like: Making a purchase Liking something Opening a specific view (pretty much every click) Inviting a friend ... The ...
0
votes
1answer
23 views

How do I prevent multiple row insert?

I set up a playground MySQL database for users and I'd like to prevent multiple row (large) inserts. That is, if there will be over N rows after INSERT operation, then raise an error and do not ...
1
vote
1answer
50 views

Some tables don't have primary key, how can I fix this issue?

I have the following message when running myqsltunner.pl in past this was not present. How can I solve this issues? -------- Galera Metrics ------------------------------------------------------ [...
1
vote
0answers
24 views

SQL Server Express 2016 high CPU Usage as soon as I log into Windows

I have a Windows Server 2012 R2 configured for ASP.net applications that connect to SQL Server 2016 Express installed on the server. This server is a VPS with 3 cores and 1.5 GB RAM. The load on the ...
1
vote
0answers
13 views

Get missing index statistics in SQL Server 2014 [duplicate]

For example consider a database that has many SP and many query execute on it using ORMs. It's very time consuming that check every SP or profile all queries that ORMs generate for performance and ...
1
vote
0answers
57 views

Fastest way to shred large xml data into a table

I have a nightly process that shreds XML data from a 17 million row table (120 GB) into another table, it takes about 3 hours and inserts about 1.5 million records. I currently do a complete drop ...
0
votes
1answer
18 views

Do dormant databases impact server performance?

On our web server, my team has been creating new databases in MySQL to manage backups. They simply create new database_DATE and copy over our live site. Which made me think today... Can having a ...
7
votes
3answers
473 views

Single service account running all SQL Servers

Is there any negative performance impact for using the same service account and agent account to run SQL Server and SQL Agent respectively for all SQL server instances running at a small company of ...
1
vote
0answers
44 views

ms/write on tempdb data files are dead slow

I don't know why writes on my tempdb data files are extremely slow. ms/write on each of the tempdb data files reaches to more than 800 ms!!! that's even after I moved the 8 equally sized (7GB) tempdb ...
0
votes
0answers
32 views

MySQL insert with sub select slow

We are using Python and LOAD DATA INFILE to load data from CSVs into our staging database. From staging we have sql scripts moving the data into our actual production database. LOAD DATA INFILE is ...
-3
votes
1answer
146 views

How to achieve high performance management of a huge list of distinct strings [closed]

I am trying to achieve high performance management of a huge list of distinct strings in SQL Server (but I'm open to suggestions of alternate platforms that might be more performant). My specific use ...
0
votes
1answer
33 views

How costly are InnoDB rollbacks?

I recently heard a fellow co-worker mention that InnoDB rollbacks are costly and negatively impact performance. How true is this statement? To give a context, we use spring+hibernate and set @...
0
votes
0answers
54 views

select * into taking too long

I have an SP where we preselect some data into temp tables using select * into. From my understanding it doesnt copy over index,constraints. For last week i have seeing performance difference for ...
1
vote
2answers
28 views

MySQL CREATE INDEX slowing down

My analytics table has 190M rows, about 150GB ins size. Storage engine is MyISAM with key-buffer-size=16G myisam_sort_buffer_size=2G myisam-max-sort-file-size=200G. Machine has 32GB memory. While ...
-1
votes
1answer
66 views

How much data in one table before it hurts performance

I'm about to develop a database for a community. The database is MS SQL Server. Each user can create their own shop where they can advertise about their products. So let's say I create a table to ...
16
votes
2answers
404 views

Using MAX text or more specific, smaller type

Someone was reviewing my DDL code for creating tables and suggested, when they saw I saw using VARCHAR(256) fields for text I expect to be pretty small, like a first name or whatever, that I should ...
1
vote
2answers
43 views

How to find out why this query is in waiting state?

I have a query that has been several minutes in waiting and is not running at all. In the SQL Developer monitor session view it shows that query has been waiting for 667 seconds? How can I find ...
0
votes
1answer
33 views

Designing database containing code metadata

I'm working on a program that disassembles programs and analyses the results. I decided to use SQLite to store the data, but I'm having trouble deciding on how to organize the data. The design I'...
0
votes
0answers
20 views

New Archive Instance or use of Filegroups

I am working with a fairly large database (1.5TB). We are looking to offload old data that is not going to change. I have done multiple searches to try and determine the best course of action but have ...
0
votes
0answers
33 views

postgresql Idle for transaction while migrating 30GB database

I'm migrating part of a mysql database into a postgresql database with a different Schema. I've written a python script, using mysql-connector and psycopg2 modules. It takes care(should) to convert/...
0
votes
1answer
115 views

Speed up query that have joined tables and function calls

I have a Bootstrap Table that use server side pagination to display results from a query like this: SELECT Item.a, Item.b, Item.c, Info1.Name, Info1.Name, Info2.Name, ...
1
vote
1answer
35 views

Count approximation with where clause

I have the following problem, we have a table of facilities for apartments that looks something like this: I would like to perform the following query SELECT crawled_name, count(f.id) AS count ...
0
votes
2answers
44 views

RMAN Overhead on the database

What is the overhead of RMAN hot backup (full backup including archive logs) being performed during business hours? Does it actually affect the performance of the database? What is the case when ...
0
votes
0answers
20 views

What are the best settings of InnoDB for FULLTEXT queries?

This question has been asked before, but I was unable to find the right answer for my situation. We have a local server with Quad core and 32GB RAM dedicated for a single InnoDB database, which ...
0
votes
1answer
113 views

Slow SQL Server 2008 R2 backups after Windows update

I recently installed a series of Windows Updates on our SQL Server 2008 R2 server. Note, these were not SQL Server updates, they were just the usual monthly Windows updates. These updates included a ...
1
vote
1answer
27 views

Perfomance of CREATE INDEX vs CREATE INDEX CONCURRENTLY in PostgreSQL

I know CREATE INDEX CONCURRENTLY is slower, but how many longer it will takes to finish in comparison with the traditional CREATE INDEX? 40% more or much more than that? I am creating an index in a ...
2
votes
2answers
167 views

Select the maximum aggregate value for a limited set of chunked/grouped rows in a large database?

I work on WordPress plugin which implements sitemap functionality. One of the steps is to build an index of sitemap pages for post entries. The logic required is roughly: determine last modified time ...
1
vote
3answers
127 views

Avoid repeated traversing of hierarchical data when parsing a big tree frequently

I have a hierarchical/tree data structure in Oracle/RDBMS where I need to traverse the tree frequently. The tree is huge and therefore parsing it every time will not be efficient. A better way could ...
1
vote
1answer
33 views

Security and Performance Implications of SQL Tuning Advisor

I work on a relatively small development team that works with an Oracle (11g) database. It's recently been requested that all the developers be given the Advisor role so that we can utilize SQL Tuning ...
2
votes
0answers
13 views

How does the use of derived tables speed up sorting?

In the article 45 Ways To Speed Up Firebird Database, it states that Use derived tables to optimize SELECT with ORDER BY/GROUP BY Another way to optimize SQL query with sorting is to ...
1
vote
1answer
142 views

How to find High CPU queries

CPU utilization is very high and the SQL Server process is consuming a lot of CPU. We have run few queries and notice that there are a few SPIDs taking a long time to complete and these queries may be ...
3
votes
1answer
119 views

.Net Application Using Inefficient Query Plan - caused by ARITHABORT setting?

One of our applications is causing a problem in that there is a stored procedure that returns fine in SSMS, in under 1 sec, but in the application its taking anything up to 10 minutes, depending on ...
2
votes
0answers
40 views

Loads of parallel inserts (OLTP) into heap table - Operation stops every now and then for 2-3 seconds

We got an analytics database and as new events are coming in we are adding them into our tempdb. From there we have backend processors that pick up the events and merge them into the right tables, i.e....
0
votes
0answers
17 views

Optimal Number of Queries Per Batch for SQL Server

I am optimizing an application for a scenario where it will import an sql file and execute over 11 million create commands, which have have some expensive subqueries that are outside my control. This ...
2
votes
0answers
88 views

High Performance Relational DB for Fast Read and Fast Write [closed]

I am looking for the best database solution for a high availability, high performance solution that meets the following requirements. Data being read, written and updated is very simple, and small. ...
0
votes
0answers
25 views

improve performance with schema design, a lot join

I'm making a custom cms system for my client, with postgresql, nodejs ... have problem with slow performance issue, when doing select data . (and it is still on localhost/mac nginx and just few data, ...
3
votes
0answers
42 views

Online text based game design - Am I linking the databases correctly?

I'm trying to recreate an old game that I used to play that went offline quite some time ago. I'm doing this as a hobby project for myself with the hope that maybe a few hundred people might enjoy it ...
1
vote
1answer
46 views

Slow MySQL query with Group by

I have a query that is taking a long time to execute minutes and more. The two tables orders and tickets have around 150k records. This is the query: SELECT orders.id, count(distinct tickets.id) ...
3
votes
0answers
57 views

Why would Stolen Memory counter be at a constant high? [duplicate]

I'm trying to understand memory stats a lot better and have been troubleshooting an issue with one of our SharePoint DB servers for a while now. Low PLE, frequent lazy writes, slow performance etc I ...
6
votes
2answers
168 views

ANALYZE TABLE..VALIDATE STRUCTURE runs forever

So, as I've mentioned before, I am a SQL Server DBA/Consultant who is helping out a customer with their Oracle databases. Mostly, I've been able to figure out what I need to and work through things ...
3
votes
0answers
46 views

Postgresql Filter Slows Query

I've got a query like this: SELECT count(*) FROM acs2014_5yr.geoheader as g JOIN tractcache as c ON (c.tract_id = g.state||g.county||g.tract) JOIN tiger2014.tract AS t ON (t.geoid = c.tract_id) ...
4
votes
1answer
62 views

Buffer Cache Size when Page Life Expectancy Drops

I'm troubleshooting an issue with one of our SharePoint databases, essentially huge drops in PLE which I think are caused by increased I/O activity (I see increased reads, writes and lazy writes at ...
3
votes
2answers
208 views

IN Clause - performance difference between listing values and query

I changed this query SELECT ... FROM linkedServer.DB.Schema.Table1 t1 LEFT JOIN linkedServer.DB.Schema.Table2 t2 ON t1.ORDER_ID = t2.ORDER_ID WHERE t1.BRANCH_ID NOT IN ( '009991', '009992', '...
1
vote
1answer
58 views

Does schema binding views affect performance?

Does schemabinding views affect performance in SQL Server or is just to prevent accidental changes?
23
votes
1answer
425 views

Logical reads different when accessing the same LOB data

Here are three simple tests that read the same data, yet report very different logical reads: Setup The following script creates a test table with 100 identical rows, each containing an xml column ...
1
vote
0answers
22 views

How to design for scalable set operations?

This is the requirement for an educational application to teach words to language learners: Learner can declare that he/she knows a given word Learner can memorize the given word (to be managed by ...
0
votes
2answers
84 views

Search entire database

Recently I was working on the database of an application that had no documentation and the database did not have any foreign keys. I needed to create a script to enforce a 10 year retention policy. It ...
0
votes
1answer
49 views

How to make a query on multiple columns without writting all possible permutations?

I'm at my first question on stackexchange, as i have a few days since I struggle on this matter: I want to make a complex query(PLSQL) on a table that has col1,col2,col3,col4,col5 having values like (...