Performance tuning done by adjusting database parameters or physical layout of the database.

learn more… | top users | synonyms

5
votes
2answers
2k views

I get ORA-13605 when trying to run SQL Tuning Advisor from SQL Developer

When trying to use the SQL Tuning Advisor from SQL Developer I get this error. Tuning advisor was working some days before.
3
votes
1answer
232 views

Find least recently used mysql table index

I am cleaning up duplicate indices from (innodb)tables in a mysql database. The database has about 50 tables. While I can check for duplicate keys using pt-duplicate-key-checker, I was wondering if ...
1
vote
0answers
484 views

SQL Server Database Engine Tuning Advisor vs DMV queries

What is the best way to tune the indexes on my production database? I normally use the following query : SELECT user_seeks * avg_total_user_cost * (avg_user_impact * 0.01) AS [index_advantage], ...
1
vote
1answer
258 views

MySQL suddenly running very very slowly

I run a PHP/MySQL website on a fairly large server with 16GB RAM and 3 vCPUs. Everything was flying along until this morning when I noticed MySQL down. I tried to restart MySQL and first got the ...
4
votes
2answers
931 views

Could running ANALYZE on all databases on large InnoDB tables show some performance increase?

So we have an old database that was fragmented until we ran OPTIMIZE on all tables. The database/tables are about 100GB in size. Tables are InnoDB with heavy read/write activity. There are so many ...
4
votes
1answer
2k views

Designing a user authenication (Roles & Rights) module

I am trying to model a User Authentication module for a MS SQL Server database that will be the back end to a Delphi UI Application. Basically, I want to have user accounts where the user belongs to ...
2
votes
1answer
200 views

How do you figure out what planner cost constants to use in Postgres?

I'm using Postgres 8.4 right now. Performance has started to become an issue as our tables have grown in size and our queries in complexity, so I've started to look into some performance tuning, but I ...
-2
votes
1answer
198 views

when to use technology like hadoop?

I understand that MySQL and others support large enough data for storing and retrieving. I am also aware of the open source projects such as hadoop and mapreduce etc.. (only their purpose and what ...
0
votes
3answers
341 views

Custom SQL Server Computer Build

I hope this is the right place to ask this question. I'm a user at StackOverflow, and when I perused the StackExchange websites, this was the best match I could find. So, if I've posted in the wrong ...
3
votes
2answers
277 views

Is it important to release memory back to the server?

I have a SQL Server 2008 R2 instance running on a production system. I'm not a DBA; I'm more a developer, but my client is currently asking me: How important is it to release memory from SQL Server ...
4
votes
1answer
2k views

Can I safely kill OPTIMIZE TABLE on an InnoDB table?

MySQL's documentation for kill warns: Warning Killing a REPAIR TABLE or OPTIMIZE TABLE operation on a MyISAM table results in a table that is corrupted and unusable. Any reads or writes to ...
1
vote
2answers
1k views

Restore data from remote server using “.sql” file

I have a ".SQL" file which contains data at a remote server. I could download that file to my local machine and import data in my local DB, but because of network issues, and the size of ".sql" file ...
3
votes
1answer
120 views

What are some key configuration settings for using an InnoDb table for session storage?

I want to start clustering my PHP app servers but don't want to go for a sticky-sessions load balancing setup at this point. However, I want sessions that are persisted to disk and implement proper ...
2
votes
1answer
275 views

what does SHOW /*!50000 GLOBAL */ STATUS do ?

What is the difference between SHOW /*!50000 GLOBAL */ STATUS and SHOW GLOBAL STATUS I saw that in few scripts and tuning presentations the first command is being used. Is there a difference, ...
1
vote
1answer
309 views

Database Tuning Advisor can't find tables across two databases

I've got a Python script which accesses two SQLServer 2008 databases. If I run it and take a trace to capture all events that occur as a result of the script, and then put that trace through the ...
4
votes
3answers
2k views

Dropped tables are not going to Recycle Bin

To start, I am a student and just getting my feet wet with Oracle. Quick history Virtual Box XP running Oracle express with SQL Developer. Created a user and tablespace for myself. (Key here is ...
10
votes
3answers
10k views

MySQL table_cache and Opened_tables

I have seen people use the comparison of Open_tables and Opened_tables to assess whether the table_cache is too small in MySQL. However, I believe that Opened_tables is cumulative across uptime, so ...
0
votes
3answers
442 views

SQL Server : primary keys advice to my whitepaper needed

I've tired to explain to every new junior developer in our r&d team why he should use Primary Keys and how to do that. So I decided to write small whitepaper, which every new developer should ...
1
vote
1answer
127 views

Is it possible to allow write-through computed columns for legacy code that expects a column to be read/write?

I have this existing table for IP storage: CREATE TABLE [dbo].[IPAddresses]( [ID] [int] IDENTITY(1,1) NOT NULL, [IPv4Address] [varchar](15) NULL, [IPv6Address] [varchar](45) NULL, ...
4
votes
1answer
224 views

Is there a way to make SQL Server's Database Tuning Advisor use more than one core?

I'm using SQL Server's Database Engine Tuning Advisor to generate recommendations for performance improvements on my database server. For the "consuming workload" step, it appears to use all ...
3
votes
2answers
744 views

Website is too slow when number of records increases?

I have developed a web application called Referral Program, It it developed by using PHP, MySQL. Users can joining the website and when they introduce new members, he/she gets a commission. The system ...
3
votes
2answers
2k views

Connection Pooling for PHP based website using Oracle 11g database

I am using Oracle 11g database server and now I am getting to see that OCI's persistent connection isn't much of a use, and a new connection is created anyway when a new user accesses the page. I ...
5
votes
1answer
377 views

Tuning queries and indexes using index analysis tool

I've been pointed to this script from several places which apparently helps with designing indexes in Microsoft SQL Server: http://indexanalysis.codeplex.com/ The problem is I'm using Sybase ASA 11, ...
5
votes
1answer
514 views

Should I use a storage engine other than MyISAM to optimise these tables or should I get better disks?

There's a production database I'm working on, whose 4 largest tables contain between 4 million and 10 million rows each and about 15 fields each, with indexes on different field types (numbers, ...
26
votes
7answers
8k views

Is it better to store images in a BLOB or just the URL? [duplicate]

Possible Duplicate: Files - in the database or not? I was wondering if there's any good reason to still use blob fields in a database. A couple of years ago I worked with a DB with a bunch ...
10
votes
2answers
952 views

SQL Server: Has anyone used the large-page allocations tuning option?

Has anyone used the tuning option of using TF834 large page allocations. I was just reading an MS article on it and was wondering if anybody had used it and seen performance gains. Are there any ...
5
votes
1answer
6k views

How do you increase MySQL performance using current server resources?

I have a MySQL database and some of my queries became slow. Query time is not stable. Most of the queries are fast, but some of them (may be that reads and returns less data) take long time. I know ...
2
votes
2answers
8k views

SGA_MAX_SIZE and SGA_TARGET

We recently increased sga_max_size to 4g from 2g but didnt increase sga_target, is it ok not to increase sga_target?? reason we wanted to increase sga is to reduce wait time on sequential reads in our ...
4
votes
2answers
1k views

Creating partitions on a production database

I have a production MySQL 5.1 database that is running well but I want to improve query performances. I have never used Partitions and just going through the manuals. I have two tables that involve a ...
4
votes
1answer
298 views

Proper Database Partitioning

I had asked a previous question "Proper technique for storing users event data" and the correct answer in my opinion was to create a database partition. Now from what I have read on it there are ...
1
vote
2answers
558 views

Performance tuning OLTP query

I have following sqls executed million times a day, single execution isnt an issue but executing million times causing some performance issues..Thanks in advance for your help! NOTE: data can change ...
1
vote
2answers
858 views

How fast should I expect to load data on a high performance computer?

I am considering a model where I use PostgreSQL COPY to copy data from a file into a table. I was wondering what kind of performance to expect on high-end hardware. An interval in MB/s would be nice ...
10
votes
3answers
587 views

Executing same request from C# VS SSMS give different execution time

I have a request like this one SELECT [EstimateId], [CreationUserId], [EstimateStatusValueId], [LanguageId], [LocationId], [EstimatorUserId], [FilterUnitSystemTypeId], [EstimateNumber], ...
3
votes
3answers
4k views

AWR Report - Tuning Database

We have an OLTP system, following are our AWR reports taken during peak hour window for three days once each day. We see a lot of direct path reads; we want to add more PGA in-order to reduce wait ...
15
votes
4answers
4k views

How can I tell WHY an insert on a certain table is slow?

I know that an INSERT on a SQL table can be slow for any number of reasons: Existence of INSERT TRIGGERs on the table Lots of enforced constraints that have to be checked (usually foreign keys) Page ...