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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139 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
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1answer
270 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, * ...
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1answer
47 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 ...
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5answers
89 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 ...
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1answer
39 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 ...
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1answer
43 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 ...
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1answer
67 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 ...
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1answer
38 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 ...
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1answer
70 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 ...
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3answers
129 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 ...
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2answers
62 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 ...
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1answer
102 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 ...
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1answer
61 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 ...
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2answers
40 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
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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. ...
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2answers
106 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 ...
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2answers
144 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 ...
5
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1answer
186 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 ...
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1answer
44 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 ...
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0answers
54 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 ...
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1answer
40 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) ...
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1answer
38 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 ...
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1answer
76 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 ...
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1answer
89 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 ...
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0answers
39 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 ...
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3answers
55 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
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1answer
93 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 ...
2
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1answer
64 views

Postgresql performance issues when issuing many small inserts and updates one at a time

I have a production web server with postgresql database. My server gets data from another server every hour on the hour. The other server wakes up and sends many requests to my server, each result in ...
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2answers
79 views

How to calculate mysql server reads per second,writes per second?

Can anyone let me know how to calculate mysql server writes,reads,deletes,updates per second.
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1answer
43 views

how big of a role does hardware play? [closed]

I'm the developer, not the DBA. I don't know much about setting up databases but i'm concern of the setup at my current work. The server is installed on desktop PC hardware(i7, 16GB RAM, 1 TB SATA ...
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1answer
46 views

Is there something I can do to make this UPDATE run faster?

I have a relation EnumeratedSensorReading that includes a siteid and a quantityid column. I want to replace these two columns with a single sensorid column. I have added this column, and it is ...
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2answers
102 views

Merge faster than Insert

Are there any advantages/disadvantages of making use of a merge over a insert function? Can an insert statement make use of the `OUTPUT' Note: the ON clause for the merge is set to 1=0 (always ...
1
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1answer
90 views

Tune Performance by putting large tables into the KEEP Pool

We currently have a database with 20GB SGA space. SQL has been optimized but has to statisfy its use cases as well and some queries are very, very slow, specifically when large result sets are ...
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0answers
15 views

ASE 12.5 - Local variable in stored proc - performance issues

I've been told many times that using a local variable inside a stored procedure (ASE 12.5) will degrade performance because it prevents indexes from being utilized. I've searched allover for more ...
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2answers
67 views

Is copy/rename a good way to improve temp table performance?

An application I am working with contains this sequence of queries at the end of constructing a large temp table; I believe it is an attempt to improve performance by pruning dead tuples - create ...
0
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1answer
49 views

Soft delete to improve performance: all wrong?

A few years back I read soft delete would improve performance of deletion, because instead of actually removing the item and impact the clustered (and all other) indices, it would just change a value. ...
0
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1answer
50 views

In MySQL why is the first batch executed through client-side prepared statement slower?

I have around a million lines to be inserted into a MySQL (InnoDB) database, so to speed things up I turned to batch/multi-line insert. To be specific, I connect to the database (I'm using Java, so ...
1
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1answer
57 views

MySQL/InnoDB - Clustering Index with UUID

In MS SQL Server it is possible to cluster an index on a non-primary, non-unique key. For example, if I wanted to create a clustered index on the insert date to prevent page splits and fragmentation ...
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2answers
60 views

Awful execution plans after migrating from MySQL 5.5.11 to MariaDB 5.5.41

We just migrated our web site database from a server running MySQL 5.5.11 to one running MariaDB 5.5.41. Everything is working mostly fine, except there's at least one query from our storefront that's ...
0
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2answers
145 views

MySQL - best practices/ how to speed up "update, else insert' queries? Insert + delete faster?

I'm running an ETL process and streaming data into a MySQL table. Now it is being written over a web connection (fairly fast one) -- so that can be a bottleneck. Anyway, it's a basic insert/ update ...
1
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1answer
69 views

Database design - load multiple excels daily

My first post ever :) Apologies if I am not so clear with my question - here I go... I have a design problem from database schema perspective. My use case is following: On a daily basis, system ...
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2answers
178 views

Many columns vs few tables - performance wise

Yes, I am aware that data normalization should be my priority (as it is). I've got a table with 65 columns storing vehicle data with columns: used_vehicle, color, doors, mileage, price and so forth, ...
1
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0answers
37 views

How to improve performance when joining against coalesce

In an effort to remove a caching layer from our application, I'm building a number of views to encapsulate the different ways a user can have access to a piece of content - one per "rule" of access. ...
1
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0answers
36 views

Performance impact in orders of magnitude with Dynamic SQL [closed]

This started as a problem debugging a SSRS performance problem where I found reports were timing out when they previously weren't. Finally I traced down the SQL the report server was submitting, and ...
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2answers
48 views

Dynamic SELECT and place result in variable columns

Edit: I use Microsoft SQL Server Management Studio, I believe it's SQL 2008R2. Sorry, new to this. I've got a complex question, at least, I think so since I can't find the answer after excessive ...
2
votes
1answer
218 views

SSRS Blocking Processes

We have a busy SSRS Reporting server (SQL Server 2008 R2) on which we see frequent blocking between the below processes: [dbo].[CheckSessionLock] [dbo].[WriteLockSession] We are aware that some ...
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1answer
59 views

mysql dump import incredibly slow on my developer's machine

I have an SQL dump, it's pretty big (411 MB) and it took 10 minutes to import on server A, the same import on my workstation B has an estimate (pipeviewer) of 8 hours to import (it imported 31 MB in ...
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0answers
65 views

Load Large data set SSIS AWS EBS

We have configuration of SQL 2012 std edition hosted in Amazon cloud that has data disk of 3 TB, Index disk of 3 TB, Log disk of 500 gb all raid 0 stripped. Am trying to load a table that has 8 ...
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1answer
40 views

What MySQL activity eats CPU? [closed]

I have noticed weird CPU consumption peaks for MySQL process. When I monitor running queries, it's empty or some reasonable queries being executed. How do I better address the problem? Is there a ...
2
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1answer
149 views

MS SQL high tempdb disk I/O during merge replication of BLOBs

Having a merge publication for replicating BLOBs (sql type - image), got very high tempdb disk I/O for my size of data. Publication is download-only and has no filters. High disk I/O is caused by ...