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
votes
1answer
650 views

What does “cleaning up” mean in MySQL InnoDB transaction status and how to prevent it?

In our database (MySQL 5.6.22 on RDS) we have a lot of transactions (~500) in a state "cleaning up" under the load: > SHOW ENGINE innodb STATUS; ... ------------ TRANSACTIONS ------------ ... ...
1
vote
3answers
622 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 ...
0
votes
1answer
21 views

RMAN Overhead on the database

What is the overhead of RMAN hot backup (full backup including archive logs) being performed during business hours? Does it actually affect the performance of the database? What is the case when ...
3
votes
1answer
768 views

Do OR conditions in Oracle SQL queries spoil index use / cause full table scan?

I have a query on Oracle 11g of the following type, which results in a series of highly inefficient full table scans: select t.Id, t.ObjectId, t...[other Tasks columns] , od1...[ObjectData1 ...
0
votes
1answer
58 views

Slow SQL Server 2008 R2 backups after Windows update

I recently installed a series of Windows Updates on our SQL Server 2008 R2 server. Note, these were not SQL Server updates, they were just the usual monthly Windows updates. These updates included a ...
0
votes
1answer
15 views

PostgreSQL vs MariaDb On Read/Write when table has about 200M Rows [on hold]

I want to build a new web application with my collected data, but I don't know witch DBMS is best choose for my Project, MariaDB or PostgreSQL there is 2 table : categories and data more than 200 ...
2
votes
1answer
29 views

Implications of many materialized views in Postgres?

I'm working on a system that includes a scheduling component, which has support for recurring events. After reading many, many posts on storing recurring events, it was suggested that they be ...
0
votes
0answers
5 views

JMX interface to an API that provides Oracle Database performance statistics [on hold]

Do we have any API that provides Oracle DB performance statistics ? I am looking for such an API and how to connect to it using JMX (if it has any JMX interface)
0
votes
0answers
12 views

What are the best settings of InnoDB for FULLTEXT queries?

This question has been asked before, but I was unable to find the right answer for my situation. We have a local server with Quad core and 32GB RAM dedicated for a single InnoDB database, which ...
1
vote
3answers
102 views

Avoid repeated traversing of hierarchical data when parsing a big tree frequently

I have a hierarchical/tree data structure in Oracle/RDBMS where I need to traverse the tree frequently. The tree is huge and therefore parsing it every time will not be efficient. A better way could ...
1
vote
1answer
138 views

What is the fastest way to clone/copy oracle databases on the same machine?

I want to clone oracle databases on the same machine and I need to change user etc. from e.g. PROD to DEV. For that I use expdp/impdp, but this tends to be slow with increasing database size. I need ...
1
vote
1answer
100 views

Select the maximum aggregate value for a limited set of chunked/grouped rows in a large database?

I work on WordPress plugin which implements sitemap functionality. One of the steps is to build an index of sitemap pages for post entries. The logic required is roughly: determine last modified time ...
1
vote
1answer
41 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) ...
5
votes
1answer
87 views

Oracle - physical writes to an index

We have a large UPDATE (affects about 200K records) on a huge table (80M records). Due to a coding mistake, the UPDATE updates the same set of rows (200K) all over again with the exact same value. ...
0
votes
1answer
15 views

Perfomance of CREATE INDEX vs CREATE INDEX CONCURRENTLY in PostgreSQL

I know CREATE INDEX CONCURRENTLY is slower, but how many longer it will takes to finish in comparison with the traditional CREATE INDEX? 40% more or much more than that? I am creating an index in a ...
6
votes
2answers
140 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 ...
1
vote
1answer
107 views

Error in loading data using DB2 load command in DB2 10.5

I have a IBM DB2 database in our application. We have a monthly Java batch process which loads data in the tables using "load Replace" sql command. Around millions of record will be updated every ...
1
vote
1answer
24 views

Security and Performance Implications of SQL Tuning Advisor

I work on a relatively small development team that works with an Oracle (11g) database. It's recently been requested that all the developers be given the Advisor role so that we can utilize SQL Tuning ...
2
votes
0answers
10 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 ...
11
votes
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 ...
0
votes
0answers
43 views

Goals for Future Database Systems [closed]

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 ...
1
vote
1answer
105 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 ...
7
votes
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], ...
0
votes
1answer
552 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
112 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
votes
1answer
257 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
votes
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
votes
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
votes
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
votes
0answers
70 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. ...
20
votes
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
votes
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 ...
0
votes
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 ...
1
vote
2answers
652 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
votes
0answers
24 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
votes
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
votes
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
votes
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
645 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: ...
1
vote
3answers
714 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
votes
1answer
352 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 ...
17
votes
2answers
11k 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 ...
3
votes
0answers
45 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
votes
1answer
394 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 ...
1
vote
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
126 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 ...