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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3
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1answer
70 views

Amazing improvement of script execution speed when split - not understood

I have an ETL job that merges data into about 20 columns of a fact table, all integer non-null (default 0) columns. There are 8 merge statements to completely update all the columns and they involve ...
0
votes
0answers
60 views

Suggestions for indexes or how to partition a table in SQL Server 2008R2

Table structure and DBMS SQL Server 2008 R2 I have a single table structure (flat) that has summarized sales data (YTD,MAT etc) by unique combinations of "Customer", "Product" and "Territory". ...
1
vote
1answer
49 views

SPID Change for a process?

On SQL Server 2012 can a process SPID change mid-operation? We have a very unique query that we've been monitoring (production, but controlled testing) and have seen it at different intervals with ...
0
votes
2answers
26 views

Good reason to convert LONGTEXT column to smaller width if field is smaller?

We have a database that uses a LONGTEXT type for a column that does not need that much space. The maximum row size currently has about 6500 characters and that's with a few million inserts so it's ...
3
votes
1answer
98 views

Improving mongodb read throughput for tiny database

I am given to understand that MongoDB will essentially perform like it is pulling records from memory if the working set is small. I wrote a simple MongoDB test program that inserts just one record ...
1
vote
0answers
33 views

problem with column oriented dbms features

I am currently looking for a free(or at least low cost) column oriented DBMS with really good compression abilities (at least 10:1 ratio) and fast response time. Having evaluated multiple open source ...
0
votes
0answers
61 views

Sql Server Stored Procedure calling table-valued function - Performance

I'm using Sql Server 2012 and I have a stored procedure that does about 15 left joins and one of those joins is a CROSS APPLY to a table-valued function. The first 14 left joins are not gonna restrict ...
1
vote
2answers
34 views

Mysql Query Take Longer To Prcoess On My Dedicated Server Than My Local Server

One of my MySQL queries takes a very long time to process on my live server compared with my development server. My live server (Windows dedicated server) is more powerful than my local (development) ...
1
vote
2answers
52 views

Database logging optimization and maintenance in SQL Server

One of the Web applications I am working on, uses NLog to log debug and error context information in the database. Basically, it performs a moderate number of inserts (I appreciate some tens of ...
2
votes
0answers
47 views

Clustered index on a fact table

I'm trying to work out what field(s) to use for the clustered index of my fact tables (which all have a similar structure). I'll use FactSales as an example: CREATE TABLE dbo.FactSales ( ...
3
votes
1answer
81 views

Finding hash match aggregate

After reading following blogs, I understand that hash match aggregate causes blocking. Using appropriate indexes it can be made as stream aggregate. Blocking/non-blocking aggregate operators The ...
0
votes
1answer
42 views

Storing mail in database, data type

I've found pretty poor informations about mail databases. My need is to archive mail messages downloaded from a normal pop3 or imap account: I am an ordinary user and I do not own the server, but ...
4
votes
2answers
227 views

SQL Server query on server taking longer than laptop

Our program uses an SQL server database as its back-end (SQL server 2008-r2 - 2014). The program is OK for performance but the Database seems to slow down a bit too much. As part of the nightly ...
2
votes
1answer
56 views

Possible causes that a MySQL/MariaDB query is slow under some table conditions

I am having a strange issue with a slow query under certain conditions: I have made a few tests and was able to isolate the issue to one single table called products_description (all the tables are ...
1
vote
0answers
53 views

SQL Server 2008R2 - BAK file backup performance issue

Just note I'm not a DBA or anything close to that. Problem: We are using SQL Server 2008 R2. We have 32 databases and backup to local disk (3PAR) using SQL Server maintenance plan. Normally it ...
0
votes
0answers
47 views

Improving query performance involving similarity and full-text search

I have been trying to improving the performance of this query involving similarity and to_tsquery. I have a table (440,000 rows, PostgreSQL 9.5.2) with the following characteristics: test_db=> \d ...
2
votes
2answers
67 views

Filtered index error when using two column condition

I created a filtered index (in SQL Server 2012) and compared it with non-filtered index – I could see promising improvement as shown below. Now I need to change the filter condition to use two ...
9
votes
3answers
12k views

How do I best measure the query performance?

I have 2 stored procedures, where the second stored procedure is an improvement of the first one. I'm trying to measure by exactly how much that is an improvement. 1/ Measuring clock time doesn't ...
1
vote
1answer
95 views

Cursor Performance in New Server

I bought a new server with spec : HP ProLiant ML310e Gen8 v2 8 GB Single Memory, Intel Xeon E3-1220v3 3,1 GHz, 500 GB SATA 7.5K RPM, Windows Server 2012 R2 x64, SQL Server Standard 2014 x64, RAID 0 ...
3
votes
1answer
44 views

Performance schema: 'stage/sql/Sending data'

Background I am using MariaDB 10.0 but MySQL 5.6 answers are also of interest. Two machines cloned from the same image, same MariaDB configuration as far as I could tell, same dataset. One machine ...
0
votes
0answers
64 views

MySQL: So many prepared statements in general log file

One of my clients complained serious performance issues in a web-application written in Java. I was suspecting that there might be some unoptimized queries which are causing the problem. I've enabled ...
0
votes
1answer
29 views

Speed benefits of Mysql Multiple Delete/Insert vs Select

I am working on a web application which involves a regular API call to the Amazon Product Advertising API. Given that Amazon limit the calls to one per second, I am looking at the fastest ways to ...
1
vote
1answer
66 views

Use of Trigger on table which can have 100 hits / second. Will it hamper performance?

Currently in one of our projects we have the following situation. The server computer is Windows Server 2008 Standard SP2. Processor is Xeon (R) 2.13 Ghz. We are running SQL Server 2008 R2. We need ...
0
votes
0answers
23 views

Performance Comparison using extended events

I am using SQL Server 2012. In my development database I have an old (MySP_Old) and new(MySP_New) versions of a stored procedure. This procedure has around 10 big queries in it. I need to compare each ...
2
votes
2answers
93 views

Filtering a result set on a very large table (using INCLUDE index in SQL Server)

Consider a very large table having hundreds of millions of rows defined as -- Here ObjectIdName and ObjectTypeName together are unique. -- Due to their size they aren't indexed, but rather they are --...
0
votes
1answer
67 views

Hashed and heap indexed object storage table insert and query performance

This question is partly to ask advice and assure this design is sane. I state the the desired properties upfront here, then go in more detail in the rationale and follow up with the design and example ...
1
vote
0answers
90 views

MongoDB with multi core instance

I have a "large" EC2 instance with 2 cores running MongoDB as part of a Replicaset. Does MongoDB use both cores in parallel by default or do I need to make some configuration change?
1
vote
0answers
60 views

sys.dm_db_index_physical_stats slow on first run after rebuilding indexes

I have a 10GB database in SQL Server 2016 RC1 on Windows Server 2012 R2 where I just performed many insert and delete operations. Afterwards, I ran: EXEC sp_MSforeachtable @command1="SET ...
2
votes
2answers
62 views

SQL Server - SQL Plan Management for baseline

I am a .Net developer. I have a database upgrade coming up (from SQL Server 2005 to SQL Server 2012). The database team will be handling the migration. But I have seen forums posts saying that after ...
2
votes
1answer
146 views

What is limiting the batch requests per sec

We have a newly created Azure SQL Server 2014 instance. The specs for the server are as follows Pretty bare bones, I know. Since this is just a testing server, we have opted to set up the data ...
1
vote
2answers
209 views

High latency with SQL Server 2014 Synchronous AlwaysOn

I've built a SQL 2014 cluster in our development environment that consists of 2 nodes. Non-Shared disks Specifications: Storage is Nimble Storage Array with dedicated LUN's presented to the ...
0
votes
1answer
29 views

Performance penalty for using thousands of tables in MySQL

Background I'm using wordpress multisite in which each user will have separate blog. For each blog, additional 15 tables are created. The website will be used by thousands of users. That means that ...
0
votes
1answer
67 views

Database design for a lot of rows with data archive

i'm new to database design on larger scale. I have some knowledge and experience with MySQL but now i have some performance issues. Currently i'm using MySQL with 3 databases: History Snapshot ...
0
votes
3answers
139 views

Increase SQL Server Performance

I have a fairly simple SQL Server 2014 Standard database with one main table. Here's the workload: I insert a row, do a few updates to it (up to 5 updates), and move on. I always update recent rows. ...
5
votes
1answer
862 views

Get minimal logging when loading data into temporary tables

Even after reading The Data Loading Performance Guide , I am still unsure if its necessary to add the TABLOCK table hint to an empty temporary table, defined with a clustered index in order to get ...
34
votes
5answers
21k views

Measure the size of a PostgreSQL table row

I have a PostgreSQL table. select * is very slow whereas select id is nice and quick. I think it may be that the size of the row is very large and it's taking a while to transport, or it may be some ...
0
votes
1answer
33 views

MySQL BETWEEN command - performance (order)

I want to create a table which will contain approx 20,000 records of three fields each. Two of the fields will contain numeric values. I want to be able to issue a SELECT BETWEEN command. One record ...
0
votes
1answer
74 views

MySQL Explain gives different result for same query, query performance changes

I've been having some performance issues on my production server. The main issue, I think is the table pricelist_entries, which has approximately 6 million rows. Basically its holds all of the ...
4
votes
2answers
2k views

Are many NULL columns harmful in mysql InnoDB?

As I explored the clustered B-tree index system of InnoDB, I think that the presence of many NULL (or small) columns has no significant effect on InnoDB performance. Does the presence of excess ...
6
votes
1answer
156 views

Why is performance non-linear if I do many UPDATEs in a single transaction

An older question covers some reasons why the performance of multiple INSERTS within a single transaction is non-linear as the INSERT count grows. Following some of the advice there, I've been trying ...
1
vote
1answer
104 views

How do DTUs in Standard and Premium performance tiers in SQL Azure compare?

We recently observed a serious performance degradation in a SQL Azure database running in Standard3 performance tier - CPU utilization went from ten percent to fifty percent to almost one hundred ...
0
votes
1answer
39 views

Select records not associated to a specific tag in a many-to-many relation

as shown in this sql-fiddle I have a bridge table events_tags representing a many-to-many between events and tags. I need the fastest way to find all events not associated to a given tag t. The ...
4
votes
2answers
277 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 ...
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 ...
1
vote
0answers
42 views

MySQL Slows Down after MYD file reaches 2GB (64 Bit OS)

MySQL seems to be writing rows OK (75,000 rows/min) until when the MYD file reaches 1.8 GB, and then the insert rate drops immensly (10,000 rows/min), and 1 hour later it's even slower (6k rows /min). ...
1
vote
0answers
30 views

Bypass stored procedure execution CPU consumption

We are using Microsoft SQL Server Agent Jobs to execute stored procedures on the other database systems (like MySQL or Oracle). Usually we run procedures via linked servers (over OLEDB and ODBC ...
0
votes
0answers
20 views

Load DATAINFILE extremely slow

I am using the code below to insert a 2.2MB file into a MySQL database in the cloud using Azure (the free version) with 36 thousand rows and 8 columns of doubles. MySqlCommand sqlCmd = new ...
5
votes
2answers
482 views

Should we create a schema per “project”?

This is a database where users create a 'project' and work on it. We have a table for project and various other tables that contain different attributes for project (multiple rows for each project ...
5
votes
1answer
234 views

SQL Server on SAN, same LUN: one logical drive vs multiple

First, let me start by saying that I did notice there are multiple similar questions to this, but neither of them is exactly what I want to ask, and not one of them has a definite answer. Second, let ...
2
votes
2answers
56 views

Is there much difference between having a key (intA, intB), or having key (longAB) where longAB is the concatenation of bytes of intA and intB?

This is a bit of an odd question. Let's go with MySQL for example. I don't know a ton about db internals. Compare two scenarios, in one, we have a table with a composite key of the from (intA, intB)...