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 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 ...
6
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2answers
130 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 ...
11
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2answers
409 views

Minimizing Indexed Reads with Complex Criteria

I'm optimizing a Firebird 2.5 database of work tickets. They're stored in a table declared as such: CREATE TABLE TICKETS ( TICKET_ID id PRIMARY KEY, JOB_ID id, ACTION_ID id, STATUS str256 ...
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0answers
41 views

Goals for Future Database Systems [on hold]

What are the features that you would like to see in future database systems ? What are some of the complicated tasks that you need to perform in current database systems that could be simplified by a ...
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1answer
68 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 ...
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2answers
13k views

How to get CPU usage by database for particular instance?

I have found the following queries to detect the CPU usage by database, but they are showing different results: WITH DB_CPU_Stats AS ( SELECT DatabaseID, DB_Name(DatabaseID) AS [DatabaseName], ...
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1answer
548 views

my.ini configuration for a huge server

I have developed a web based app in PHP MySQL and Flash Builder. It was running fine until a few days ago when the client began to connect a lot of users. Then the app started to freeze and sent ...
3
votes
1answer
108 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 ...
0
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1answer
256 views

How to track IOPS statistics?

Is there a way to access statistics about IO operations per second in DB2 9.7? I am not interested in the buffer pool hit ratio, just IOPS.
0
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1answer
131 views

Query running slow on script and producing error 500 when run in phpmyadmin

I have a query that seems to take a good 30 seconds to execute even when the query produces no results. There are 4000 lines within the database and queries that produce all results run within ...
2
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0answers
38 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, ...
16
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5answers
15k views

What's better for large changes to a table: DELETE and INSERT every time or UPDATE existing?

I am making a project where I need to change around 36K records in one table daily. I'm wondering what will perform better: delete rows and insert new ones, or update already existing rows For me ...
2
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0answers
65 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. ...
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4answers
10k views

Is nested view a good database design?

I have read somewhere long time ago. The book states that we should not allow to having a nested view in SQL Server. I am not sure the reason why we can't do that or I might remember incorrect ...
0
votes
1answer
179 views

Application is hanging when database upgraded from SQL Server 2000 to SQL Server 2008 R2

Presently we are working with SQL Server 2000, the database is perfectly working with our software for retail sales counter application developed with VB 6.0. But after upgraded to SQL Server 2008 R2, ...
0
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0answers
15 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 ...
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2answers
82 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 ...
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2answers
649 views

Mysql improve Self join performance large table?

I have a task to help identify conflicting IP ranges , I want to highlight when one companies IP range falls within another's ... below is the sample table, I have converted the IP ranges from .dot ...
0
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0answers
23 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
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0answers
55 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 ...
3
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0answers
40 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 ...
14
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2answers
357 views

LOB_DATA, slow table scans, and some I/O questions

I have a rather big table with one of the columns being an XML data with an average size of XML entry being ~15 kilobytes. All other columns are regular ints, bigints, GUIDs etc. To have some concrete ...
3
votes
1answer
644 views

Select * from statement execute very slowly, innodb io read speed is low

I have a very simple query " select * from ap_statistic " running in my servers. the servers have the same hardware and software configuration (CPU 8 core, mem :32G, OS: redhat 5.5, mysql version: ...
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0answers
36 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) ...
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3answers
705 views

Oracle Compatible Parameter to set

Is there any difference in setting the Compatible Parameter to 11.2.0.0 vs 11.2.0.4 ? Are there any advantages / dis-advantages ?
0
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1answer
349 views

Large long-running reporting queries are causing very slow new mysql connections

Usually, mysql's connecton time is in the 0.001 second range. However, when I run a large reporting query (that spans multiple tables with aggregates), I get tons of warnings saying that new mysql ...
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2answers
10k views

Configuring PostgreSQL for read performance

Our system write a lots of data (kind of Big Data system). The write performance is good enough for our needs but the read performance is really too slow. The primary key (constraint) structure is ...
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0answers
44 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) ...
22
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1answer
387 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 ...
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1answer
1k views

Creating indexes with t-sql scrips vs rebuild indexes in maintenance plan

I’m using SQL Server 2008 and I am running several (15) scripts each day to bulk insert to tables. Each script drops the table at the beginning. I create indexes in the scripts. Some of the scripts ...
7
votes
2answers
19k views

SQL Server becomes slower over time until we have to restart it

We have a database with a mixed OLAP/OLTP workload. The queries are quite ad-hoc and are dynamically created in the mid-tier application server. When we start the server, the performance is quite ...
8
votes
1answer
21k views

SQL Server 2008 R2 high Buffer I/O causes

Am trying to troubleshoot performance on a SQL Server that we have for our document management server and today performance has hit an all time low. Looking at the Management Data Warehouse (MDW) I ...
2
votes
2answers
124 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 ...
5
votes
2answers
9k views

Very slow DELETE in PostgreSQL, workaround?

I have a database on PostgreSQL 9.2 that has a main schema with around 70 tables and a variable number of identically structured per-client schemas of 30 tables each. The client schemas have foreign ...
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2answers
195 views

Please recommend changes for my.cnf

I am not having any performance problems per se but want to improve my sites' performance if possible. Would appreciate any advice for how I can improve my.cnf. I have just one server, not ...
3
votes
1answer
51 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 ...
1
vote
1answer
47 views

Does schema binding views affect performance?

Does schemabinding views affect performance in SQL Server or is just to prevent accidental changes?
0
votes
1answer
245 views

MySQL Config for server with 8gb RAM and 4 cpus

I have a server with 8gb ram and 4 cpus. I don't have enough time for testing and bench marking so I would like to get the advise of experts like you guys, let me know if something is wrong with my ...
0
votes
1answer
27 views

MySQL 5.6 performance_schema not showing queries from application

I'm seeing a strange problem with perfromance_schema... it seems queries are not getting logged as I expect them to be. For example, this is what I get: mysql> SELECT `SCHEMA_NAME`, `DIGEST_TEXT`, ...
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vote
4answers
243 views

mysql need help optimizing query

I have a table containing servers logs, and another table containing rules to match certain and drop them. The logs tables contains around 1 million rows, and there are about 20-30 rules. The ...
3
votes
2answers
191 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', ...
2
votes
2answers
2k views

Improve MySQL Query Performance - Too many records

I am using MySQL RDMS for a contact management system. Now a days my database grew in size and contains more than 1 million records. Checking duplicate phone numbers became a big issue during ...
2
votes
1answer
175 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
votes
2answers
2k views

How to configure my.cnf for Mysql 5.1, which is using too much CPU?

I am new Database engineer. I am having trouble in my server which is using too much CPU on database query(simple count statement). I have googled about it, so i found out it depends on system ...
0
votes
1answer
319 views

memory usage oracle query

We see Direct path read temp frequently in the database. It started with one query and later followed up to all the queries running in database at that moment. I understand that data is read from ...
1
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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 ...
2
votes
1answer
537 views

Database design for a table with both bulk insert and single row insert

I have to design a table where records will be inserted in two ways. Bulk insert from a batch process from a delimited text file between 2 - 3 million rows in a short burst. Later the same records ...
0
votes
1answer
42 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 ...
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2answers
22 views

Quick and easy ways to check SQL/DB performance [closed]

We host a web application for customers, sometimes they call in and complain of slowness. I was asked to have a list of things to check from network down to the application. For SQL, can any suggest ...
2
votes
2answers
167 views

Deciding EC2 Instance type & Volume IOPS for Mongo DB

We have 500GB data in our Mongo(v2.6.3) including the indexes. We currently run this on AWS m3.large(8GB RAM) instance. Yes, Single machine. Our MongoDB Cloud Manager shows these stats: ...