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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1answer
194 views

CPU Time Slower in SQL Server 2014 than in SQL Server 2008 R2 [closed]

We’re upgrading a virtualized database server from an old SQL Server 2008 R2 Standard (vmware) to a new shiny SQL Server 2014 Standard server (hyper-v). We were doing some performance testing and to ...
2
votes
0answers
62 views

Query that can benefit from index, cluster or hash-cluster

I'm trying to find a equi-join query that shows a decent performance bump when I use an index, cluster or hash-cluster structure on my data. I initially need to run the query on unstructured data ...
2
votes
0answers
100 views

Every time I run a stored procedure it takes longer to complete until I restart the SQL Server [closed]

I need to optimize a critical stored procedure running on SQL Server 2012. The idea was to measure how long it normally took to run this procedure, make a few changes, measure the improvement and ...
0
votes
1answer
62 views

Is it possible to break down query time?

We have a setup of a few cloud servers that connect to a MySQL cluster on dedicated servers over Rackspace's Rack Connect network. We have noticed recently that the time for database queries (via PHP) ...
2
votes
1answer
225 views

CPU Time Slower in SQL Server 2014 than in SQL Server 2008

We’re upgrading a virtualized database server from an old SQL Server 2008 R2 Standard (vmware) to a new shiny SQL Server 2014 Standard server (hyper-v). We were doing some performance testing and to ...
0
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0answers
40 views

Non-structured Query performs better than on clustered, hash-clustered and indexed?

I am using the following query as a base line on some unstructured data (no indexes, no clusters etc) and the query is performing better on the unstrutured data than when I add indexes to the join ...
8
votes
3answers
189 views

Poor cardinality estimate disqualifies INSERT from minimal logging?

Why is the second INSERT statement ~5x slower than the first? From the amount of log data generated, I think that the second is not qualifying for minimal logging. However, the documentation in the ...
0
votes
1answer
148 views

Slow mysql query full text search tag database

In the database are ~700k images. Each image has its own tag(s). I want to be able to search images by the tags with a full text search query. The query does exactly what I want but it's very slow. ...
2
votes
1answer
37 views

Excluding rows by lots of ids

I need to exclude some rows that the user has already seen. Currently I am doing this by simply comparing the ids that the user has seen to the row's ids by running this query (there are also other ...
1
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0answers
231 views

Two servers with the same exact specs taking way different times to run the same query

I have 2 servers with the same exact specs: Test Server and Production Server The same exact database with the same exact data is on both of these servers. I remote into each server using remote ...
0
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0answers
37 views

Query performance tuning with joins on views with large data

I've this query in oracle. This is basically the query of a BA report which I'm trying to tune. SELECT DIM_PROJECT_OL.PROGRAM_ID, DIM_ANALYTIC_STRUCT_ACCOUNT_OL.STRUCTURE_ID, SUM(NVL(...
0
votes
1answer
137 views

How to profile trigger database performance impact

I want to set up some triggers on a DB2 box (LUW, 9.7). The DBAs are concerned that if the trigger fires too often, it will adversely affect general performance. What's a reasonable cheap approach ...
1
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0answers
56 views

Identify a blocking process in MongoDB

I have a single MongoDB instance is performing quite badly. I noticed that db.currentOP().inprog.length quite often becomes quite big, sometimes even goes up to 100. When I drill down to the actual ...
2
votes
1answer
94 views

Computational power required for this query

I am not sure if the query I am trying to run is unreasonably large, in terms of computational power. The query will identify islands (and their duration) of a certain condition in my db. Things work ...
5
votes
1answer
779 views

Should I use UUID as well as ID

I've been using UUIDs in my systems for a while now for a variety of reasons ranging from logging to delayed correlation. The formats I used changed as I became less naive from: VARCHAR(255) ...
3
votes
0answers
54 views

Isolate database performance on an instance

I have SQL Server 2014 Standard Edition installed on a machine with two different users and two catalogs, each of them accessed by a different user (each user is strictly tied to his catalog). Is it ...
6
votes
4answers
488 views

How can I Debug a Buffer Issue?

I have a production "Microsoft SQL Server 2012 (SP1) - 11.0.3128.0 (X64)" that is showing weird buffer and page life expectancy (PLE) symptoms. I am running this every minute on my server (to track ...
4
votes
2answers
116 views

Nested table hierarchy: foreign key duplication vs. join

I have a nested table hierarchy, similar to the following one (this is an example but demonstrates the schema well enough): +---------+ +---------+ +---------+ +-------------+ | users | | ...
2
votes
1answer
378 views

What is the best index implementation for a really large databse

I have a really large SQL SERVER table with only non clustered indices for several columns , while querying the table the execution plan shows RID Lookups , i expected to see this kind of lookup ...
6
votes
1answer
201 views

Performance problem after migration from SQL Server 2005 to 2012 [closed]

Last Friday, I migrated a SQL Server instance from 2005 Enterprise Edition to a brand new Windows Server 2012 server with SQL Server 2012 Enterprise Edition installed. Since then, users have started ...
0
votes
1answer
245 views

Database-design for a small filter / search tag function

I'm building a search function in php for a database with 1k to 4k articles. It's going to be built on a tag system. I've been reading some tutorials, blog posts, q&a etc about it. Most important ...
2
votes
1answer
107 views

Understanding performance of highly unique WHERE clauses

I've been struggling to understand how to deal with a specific type of performance issue that shows up very often in this scenario: when you are wanting to apply multiple filters in a query, but you ...
-6
votes
1answer
40 views

Changing numbers in a where clause on the same SQL can it make faster or slower [closed]

I just received a question from one of the developers and the question is, he ran a SQL statement with a where clause and when he puts 004 the SQL finished very fast, and on the same SQL when he puts ...
0
votes
1answer
176 views

Convert UNION query to JOIN. Is it actually needed for high performance?

I have the following table structure in MySql. To get the list of roles for a particular user, I use the following union Query, SELECT r.ID, r.ROLE_NAME, r.TENANT_DOMAIN, r.PROVIDER_ID FROM `...
1
vote
0answers
83 views

Postgres search and replace

What is the difference between the search in search and replace, (the replace function) and full text search (tsvector) in Postgres? Or, put another way, can tsvector be used in search and replace (...
1
vote
0answers
42 views

SQL Server on big machine falls over inexplicably

We've been doing some throughput testing with our web application. The production application resides on a couple of machines in the amazon cloud, consisting of a web server and a database server. ...
2
votes
2answers
97 views

MariaDB server with 80K-100K DataBases

BACKGROUND : We have an environment where there is a new DB created almost every minute and it will be Dropped after few days or weeks (maximum 1 month) such that the space used is about 300GB~400GB ...
4
votes
0answers
197 views

How can we improve this PIVOT operation? ( SQL Server 2008 R2 )

We have this query, that runs in 1:10. We need to improve this. This is just a test query, but we will implement this upgrade on our real query. select top 100 * from ( select codCliente ,...
5
votes
1answer
464 views

Slow fulltext search for terms with high occurence

I have a table that contains data that is extracted from text documents. The data is stored in a column called "CONTENT" for which I have created this index using GIN: CREATE INDEX "File_contentIndex"...
0
votes
0answers
112 views

How come MySQL LIKE is faster then FULLTEXT?

So, I was trying to optimize my MySQL queries, but found out that i'm actually doing this wrong. I've changed my query from using SELECT * FROM test WHERE tst_title LIKE '1%' To: SELECT * FROM `...
1
vote
2answers
81 views

Duplicate Same Table for Multiple locations

We have an "appointments" table with following schema. appointments(app_id,.....,app_type,location_id) app_type - type of appointment location_id - keeping the location for multiple location setup. ...
1
vote
0answers
48 views

3 tables joins performance issue

DB: Postgres 9.4 schema: table a: id, score table ab: a_id, b_id, b_type table b: id, name, type I am trying to get top 10 result in the following format: name, count(group by name), average(...
0
votes
0answers
58 views

Identifying high load sql

We had an oracle outage some days ago. We have inbetween awr tools. I genarated awrrpt report but dont see anything suspicious. Which report should I generate to see sql, which caused very high cpu ...
0
votes
1answer
54 views

Is it good to save Keywords stored by users in a new DB schema?

My question is more from the schema design and of further performance of the DB. I'm designing a DB schema which will store primarily strings. Actually, users work on these string, as normal mortals, ...
1
vote
3answers
874 views

Fastest way to do bulk import in MYSQL

I have got a question about the fastest way to copy a large number of records (around 10 million) from 1 table to another in MySQL. The target table has 1 primary key, 4 indexes and 3 foreign key ...
2
votes
1answer
70 views

Deleting large amounts of cascading records with minimal locking

I'm looking for a strategy to purge large amounts of logically deleted data from a MySQL database. The deleted records are in a relatively small table, but are referred to with many ON DELETE CASACDE ...
2
votes
1answer
566 views

Slow inserts in oracle 12c inmemory table

We are running some tests to check the in-memory performance on a 12c (12.1.0.2.4 EE) RAC. Servers have 56GB memory and 20core CPUs. Our plan is to have a few read-performance critical tables in ...
4
votes
3answers
361 views

Setting maxdop 1 vs setting the threshold for parallelism high

I am looking at a possible fringe case for parallelism settings. I've long since followed the credence that maxdop 1 is a viable option for Microsoft Dynamics CRM databases. As the nature of the ...
5
votes
1answer
127 views

How can I minimize impact of expensive queries in Database A on Databases B, C, D

How can I configure SQL Server so that activity in 'Database A" has minimal impact on users in 'Database B' The Context Our (very large) production SQL Servers have a lot of databases on them ...
0
votes
1answer
103 views

MongoDB 3.0 Indexes maximum limitation

I have a mongo DB that store user's public messages. Each message should be categorized by at least one TAG (3 max in an array) The TAG can be anything up to 32 characters. ([0..9a..z]) the Tag ...
0
votes
1answer
125 views

Mysql Slow when join query running increaed

Our Mysql dedicated server box always have around 40 - 80 active user connection , so the query speed very good and Cpu usage low . (around 4 - 8 core from 24 core) but sometimes when some wordpress "...
3
votes
1answer
117 views

4m Rows in MySQL, ~5 Minutes to Run Query

I have 2 tables, a users table and a log table which literally logs each time a user signs in. What I'm trying to do is grab a list of all users with a certain rank who have not logged in for over a ...
1
vote
1answer
351 views

Why is my Target Server Memory slightly higher than my Total Server Memory?

I'm doing a performance test on a high traffic (16000+ users, estimated 1000+ concurrent at peak) Microsoft Dynamics database. The server has gone on line a few months ago, and I'm doing some tests to ...
1
vote
0answers
75 views

Speed of Split Database vs ODBC with SQL Server vs ODBC with Azure Cloud

I would like to be able to host my data either in the cloud or in SQL Server, as having all my data in one Access file just doesn't seem the most secure to me (or am I wrong?). My forms contain many ...
0
votes
1answer
74 views

Creating index for large table is taking forever

I am trying to create Index for a large table with row count of 496,000,000 and the database is on SQL Server 2012 Enterprise edition. I know how to create index but its taking forever and would like ...
3
votes
1answer
156 views

ASP.NET & SQL Server 2012 timeouts once a month

We have an intranet site which works fine, except one day a month. There are slow queries, unoptimized tables, tables with ~8 million records, etc. but daily usage is fine, although some ...
1
vote
0answers
112 views

Upsert - Should I verify the row exists first, attempt an update, or try to insert first?

In a software that I'm working, I have a table with a few columns and a id. In some events in my software, I need to update some column of a record with a certain unique field (other column), but ...
4
votes
2answers
284 views

Creating MSSQL Performance Baseline Monitoring

In order to get an overview and compareable data my current task is to create a performance baseline to get some figures about the different productive sql instances. My thoughts are: I want to ...
1
vote
1answer
88 views

Things to keep in mind while editing Mysql “my.cnf” file

Today I tried to boost mysql's(installed in my system Ubuntu 14.04) performance as I have many sites(PHP/Magento) installed in my system which relies on mysql as database server, but when I edited the ...
0
votes
2answers
65 views

Identical SQL Server databases hosted in the same physical DB server

We have hosted similar SQL Server 2014 databases TestDB and TESTDB_Copy on the same physical server. The two databases are almost the same and there may be minor differences in the number of records (...