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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2
votes
2answers
46 views

SOS_Scheduler_Yield wait type

I am having a process that has a last_wait_type as SOS_Scheduler_Yield and is inserting 100 records to a table. This process has been with this wait type forever with low CPU utilization %. There are ...
0
votes
0answers
56 views

Oracle Performance on 2 servers

I have the same database on two different servers(production and test) with major differences in query time as follows: Query1: SELECT distinct dms_get_FAST_serverpath(d.id) full_name FROM ...
3
votes
1answer
53 views

Why does it take so long for Postgres to return a sequence number?

I have an application that does bulk loads into a large table (100 million rows). I am using Postgres' COPY FROM functionality to load data from a flat file. The target table has a primary key of id. ...
2
votes
1answer
48 views

How to make a query using “where MONTH(datetime)” faster?

I already tried to add an index on the datetime column, but the result is still unacceptably slow. SELECT s.id, s.player, COUNT(case when dg.winner = 1 AND dp.colour <= 5 then 1 when dg.winner = 2 ...
7
votes
0answers
58 views

Two servers, different execution plans. Several orders of magnitude difference in run time

Two servers, Development and Live. Live server is an Amazon RDS SQL Server Web instance. Both servers have identical schema and data. There is a good spatial index on the geometry column. On my ...
3
votes
2answers
60 views

MySQL - Where can I find metrics on the performance of Blob vs file system?

I know and understand that there are performance hits in storing blob data in the database, but the blob portion of the data is going to be rarely retrieved/viewed, it is for smaller data (the vast ...
2
votes
1answer
164 views

Excessive CPU use in vendor SQL Server DB

Background: I've got a SQL Server 2012 DB provided by a vendor so modification of queries and tables is limited. We do own the DB though, so we can add and maintain indexes. Indexes haven't been ...
0
votes
2answers
75 views

Managing tables in database

I am new to web development field and particularly very poor at database management. I am developing a web application which resembles Project Management System where new companies can add their ...
3
votes
0answers
52 views

How to do Statistics in Partial Indexes of PostgreSQL efficiently?

This answer motivated think again my following tables but I am still uncertain how to store statistic data for quick selection. I think it is well done with partial indexes because only a subset of ...
1
vote
1answer
46 views

Update records from one table to another in different databases where condition is accomplish

I have two tables stored in two differents DBs and I need to perform some sync between both tables based on lastmodifieddate and lastSyncAt. Let's call them as db1 and db2. This is the DDL schema for ...
2
votes
1answer
62 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 files ...
1
vote
0answers
60 views

Measure SQL Azure Transaction Rate

We are on SQL Azure v12 Standard/S2 Service Tier and are not satisfied with the performance so I am trying to measure where the bottleneck is. I realize that we could be hitting the limits of the S2 ...
1
vote
1answer
34 views

How to write marker messages into the MySQL general_log?

I'm build a performance testing harness for our distributed web app. I'm using JMeter to drive it by simulating poorly performing parts of the app from the web side. I've set up MySQL to log to the ...
2
votes
0answers
86 views

Transaction log bloat when writing to table on replicated database with parameterized filter

We are observing abnormally large log writes whenever we update a table that is used for parameterized filter in a merge replication. There are a number of join filters as well. When executing a ...
1
vote
1answer
113 views

What is the best option to easily fix fragmented heap indexes?

I have SQL Server 2008 R2 SP2 and also SQL Server 2012 SP2 on these servers. I have a database in which there is a lot of heap indexes which are more than 90% fragmented. What is the best option ...
2
votes
0answers
73 views

No significant performance increase after migrating from SQL Server 2005 32bit 4 Cores 4 GB RAM to SQL Server 2012 64bit 4 Cores 32 GB RAM [closed]

We run regularly a series of data analysis scripts on one of our databases. The MDF File of the database is several gigabytes big, the scripts perform not only selects, but also inserts, updates and ...
5
votes
0answers
74 views

Which to trust?

We are troubleshooting a long-running issue with a vendor. Their software has a tendency to freeze up and stop working once or twice a week causing major disruptions to our operation. They have been ...
0
votes
1answer
58 views

Best approach to compare specific columns of 2 tables in different databases?

I'm running an application who does have a shorten version of a table in the backend database. Both application- and backend-tables are having the same primary keys and some specific key columns. ...
0
votes
2answers
97 views

How can i update my database from another database using temporary tables?

I want to update tables of my database using another big database every day with using temporary tables and without returning result. How can i update it? This my temporary table : use data_pro; ...
1
vote
1answer
45 views

MySQL Read/Write Benchmark

I'm trying to benchmark Read/Write speed in MySQL 5.5. Currently I have a stored procedure that insert rows with random numbers to a table and I'm measuring time of execution before and after ...
5
votes
0answers
198 views

Why is my Azure SQL Server so slow?

We currently have a VM that is very underpowered and are proposing to move to an Azure VM with better specs. The problem is, the Azure VM is much slower than the original VM even though it is of a ...
3
votes
0answers
84 views

Why the stored procedure is much slower than a temporary table? [closed]

I want to do the updating of my database every day and I will like to use stored procedures but the time of execution of the temporary table is faster than the stored procedure. How can I optimize my ...
7
votes
0answers
133 views

Why is query thousands of times slower with DESC?

I have a PostgreSQL database (AWS RDS) and ran the following queries in psql: livenet=> EXPLAIN ANALYZE SELECT * FROM outputs ORDER BY height LIMIT 10; Limit (cost=0.57..36.82 rows=10 ...
1
vote
1answer
154 views

Why is my stored procedure very much slower than the same MYSQL query? [duplicate]

My stored procedure is very slow compared to a normal query or a temporary table. How can I optimize my stored procedure? CREATE DEFINER=`datasll`@`...` PROCEDURE `product`() BEGIN EXPLAIN ...
11
votes
1answer
281 views

Why does referencing a variable in a join predicate force nested loops?

I came across this issue recently and couldn't find any discussion of it online. The query below DECLARE @S VARCHAR(1) = ''; WITH T AS (SELECT name + @S AS name2, * ...
1
vote
1answer
52 views

Intervals query of huge data

My question is more or less theoretical - what is the best approch to get query data by intervals. The situation I have a system that manage counters (thousands of counters - counts consumption of ...
1
vote
5answers
117 views

TSQL insert table using view — performance issue

I have a big view joining multiple tables that in a regular basis materialists itself into a table (this step occurs for viz's tool read a table instead of a view during data source refresh): select ...
0
votes
1answer
41 views

Get all possible parent ids only if has parent bigger than 0

Right now If I call get_parent_id(4) I will get all id parents. This means 3,2,1. Is not hard to guess that 1 has parent 0. This is my problem. I want to output all ids unless the parent is 0. To do ...
0
votes
1answer
48 views

RDS Postgres Peformance

I have recently set up a new RDS instance to test out working with a AWS postgres instance vs a heroku postgres instance. What I've found is that when I load an instance of 1000 entries in RDS its ...
0
votes
1answer
88 views

Using TEXT or even MEDIUMTEXT for all text columns in a MySQL table?

I'm using a PHP script to insert millions of rows into a MySQL. Each of the rows contain a diversity of columns that are very different across the rows. Basically I'm using MySQL as a key-value pair ...
1
vote
1answer
54 views

Disk Read IO Throttle not showing in perfmon Windows Server 2012 r2

I am working on Windows Server 2012r2,SQL Server 2014. I am trying to create a new data collector to review Disk IO in perfmon. When I get to the step to add the available counters there is no Disk ...
0
votes
1answer
96 views

SQL Server Data File/Log File poor performance

I've been asked to look at a database/application server that's "performing slow". No one could really tell me what was performing slow (except for the database backups) so this has been a discovery ...
1
vote
3answers
183 views

Are TEXT fields stored separately from the row in MySQL-ISAM?

We have a "notes" table and some of the queries are getting very slow even though we're not searching on the note contents. We're wondering if moving the note content into a separate table would speed ...
1
vote
2answers
72 views

High SOS_SCHEDULER_YIELD and Signal Waits

I have run Paul Randals wait script and can see SOS_SCHEDULER_YIELD is at 60% with an average signal wait of 10ms. I have also run a script to find out the what percentage of my waits are signal ...
1
vote
1answer
208 views

Indexed VIEW in SQL Server with PIVOT

A simplified version of my problem is as follows: I have three tables Records, Inputs, and Outputs. Records Id DTS   1  2015-01-01 00:00 ... Inputs Id RecordId ...
0
votes
1answer
75 views

Divide a PostgreSQL database into schemas

My Postgres database will be focused on multidisciplinary organizations. The project axis is: a person could belongs to diverses disciplines (ex: arts, sports) for the same organization, and this ...
1
vote
2answers
54 views

Will frequent small select queries slow down frequent write queries in InnoDB table in MySQL?

I'm running a MySQL database with tens of tables in remote server. To monitor the data, I write a small program to query to database via VPN connection every 10 seconds. Each query is a union of 20+ ...
0
votes
1answer
37 views

mysql Quiz leaderboard filter by points, time taken

I have a quiz report table which shows a report for every quiz a user takes. I need to create a leaderboard from this, which shows the top users best score, filtering by points and then time taken. ...
1
vote
2answers
121 views

Slow “CREATE TABLE” and “TRUNCATE” on MySQL / MariaDB

I am fighting with performance issues on a local MariaDB instance. Fun thing: I previously had problems with all my INSERT and UPDATE and DELETE queries. This got signigicantly faster (~40ms -> less ...
2
votes
2answers
173 views

Slow Performance caused by Correlated Sub-queries & Clustered Index Seek

I'm running a query in which one of the tables (FIELDDATA) has nearly 400,000 records which is taking more than 2 minutes to execute. I ran the execution plan, and noticed that the clustered seek ...
4
votes
1answer
222 views

Sudden poor SELECT performance on a large table with existing indexes

My company uses a software suite in which the only thing I can truly modify is the database. We've always had performance issues (mostly hardware problems that we hope to resolve soon), but lately ...
1
vote
1answer
49 views

Migration from SQL Server 2012 Ent to SQL Server 2014 STD

We recently migrated from a traditional hosting environment with a back end of SQL Server 2012 ENT to an Azure VM running SQL Server 2014 STD. We did all the cool stuff with BPEs on SSD, etc. The ...
0
votes
0answers
64 views

Tuning a Postgres INSERT only database

I am designing a database which will have many inserts and selects, but no updates. Are there any considerations to take (in order to have high query performance) while knowing no tuple updates will ...
1
vote
1answer
45 views

MongoLab: Does hardware effect performance of a find() query [closed]

I asked a pervious question on StackOverflow about if document size affected the performance of fetching that document (the document is 3MB in size) ...
0
votes
1answer
51 views

Load & traffic balance best practices

I am about to design an enterprise solution for a large scale application in which a windows service, MVC, and many other projects will use a database, so I am thinking about load balancing and best ...
0
votes
1answer
108 views

Optimizing key lookup in subquery with UNION ALL

I am trying to optimize following query (little bit more complex actually, but this is important part): SELECT Id, StatusDate, [...Lot Of Columns...] FROM ( ( SELECT Id, StatusDate, [...Lot ...
6
votes
1answer
102 views

Capture and Replay workload

We have a new server which we are migrating too and want to see the potential benefits of the hardware. So the idea is that we capture a workload and replay this against our new box. My question is ...
3
votes
0answers
40 views

SQL Server Disk IO Performace appears different between otherwise identical servers [closed]

I have two identical servers each running Microsoft SQL Server and performing a batch processing job. Server #2 keeps timing out while processing while server #1 appears to be running smoothly. I ...
2
votes
3answers
57 views

Is database performance optimization independent of the size of a database or a table?

If by rewriting an operation or a piece of code the performance has increased by 30% in a program reading and writing to a table with 100,000 records, does that optimization remains same if the table ...
3
votes
1answer
132 views

Pagination performance, with subquery, inner join and where

I am trying to optimize following query (this is most simplified version I could came up with): SELECT tr.Id, StatusDate FROM ( SELECT tr.Id, tr.StatusDate FROM mon.ArchivedTaskResults_201504 ...