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

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35 views

Retrieve list of matched words in PostgreSQL

I'm new to PostgreSQL and really more than your more basic queries/inserts. I've created a TSVector column to my table that I'm searching and have set the column to look at the specific column in ...
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2answers
3k views

How to optimize MySQL for large BLOB updates

I have a table that holds large BLOBs (up to 10M), and is updated frequently. The problem is that UPDATE statements can take up to 1 second to execute, and due to app design this blocks UI. I need to ...
6
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1answer
682 views

Optimizing PostgreSQL for transient data

I have several tables with 100-300 columns of integer types each, that hold highly volatile data. The datasets are keyed by one or two primary keys, and when refresh occurs, the whole dataset is ...
5
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1answer
539 views

How can a fill factor of 0 or 100 be the same?

As of my understanding, Fill factor of 80 implies that 20 percentage of each leaf-level page will be empty to enable future growth. I can't correlate how fill factor of 0 and 100 can be the same! Am I ...
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1answer
80 views

Indexes and Optimizations for Logging System

I'm designing tables for a new log system and am having trouble figuring out what indexes I'll need (I'm a developer, not a DBA), and am also open to any suggestions/criticisms/etc. for making the ...
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5k 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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2answers
237 views

Tuning advisor with Extended events?

With SQL traces I was able to analyze them with Database Engine Tuning Advisor to obtain basic recommendations for perf. tuning(missing indexes, statistics,...). Now, with SQL 2012 and Extended ...
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2answers
1k views

Slow SSRS Report in production

I have an SSRS report which gets its data by firing a series of stored procedures. Now the report is timing out big time when run in production, yet when I pull down the prod database and restore to ...
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2answers
8k views

Is my.cnf for mysql 5.5 is suitable and well tuned for below hardware spec?

My Hardware Spec Technology: Ivy Bridge CPU: Intel Xeon E3 1245v2 Intel Smart Cache: 8MB Cores / Threads: 4 / 8 Frequency: 3.4GHz+ / 3.8GHz Turbo Boost RAM: 32 GB DDR3 Hard disk: 2x 2TB SATA3 Raid 1 ...
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1answer
610 views

What causes InnoDB to write 100% more pages while slowing down answering queries?

I have a somewhat big database server: 4 processors, 32 cores, 288GB RAM, 2 ethernet cards bounded together, 2 independent RAID controller cards with 1GB cache each, 24 2.5" disks, being 8 SAS, ...
5
votes
1answer
112 views

How to tell if database tuning is fruitful (PostgreSQL)

As a DBA, I regularly observe my database, tune up some queries (either getting the programmers to re-write it or add index or update statistics if that's what is needed, etc). I also tune up the ...
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0answers
291 views

PostgreSQL can't start after tuning some options

I'm having some issues with "too many clients" and I tried to change the max_connections param (currently 100). I tried to set some value like 300, but when I restart the service, I got this ...
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1answer
183 views

sp_setapprole taking 100 - 200 ms [closed]

SQL Server 2008 SP1 here. We have a machine where sp_setapprole calls take more than 100ms and they are done many times per user operation on an application. The developer says that in his setup, ...
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1answer
507 views

Need help with long running query

UPDATE: Adding a clustered index to each work table covering all fields reduced the query run times to su-bsecond. I consider this question closed. Thanks for taking the time to read this post - ...
2
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1answer
113 views

Slow Query Gets Even Slower After Indexing

I have a MySQL database with just one table containing 8 million records. I need to query the table to find a single record that matches a specific number: select * from my_table where ...
0
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0answers
46 views

Oracle User Profile for REST API

What sort of profile would you recommend for an Oracle user that is manifested through a RESTful API; particularly where there will be a lot of asynchronous requests? So we're talking about a ...
0
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1answer
1k views

How to change page size in an existing sybase database

I have an existing database with 1 kb page size i want to increase that to 16kb and increase cache to take advantage of my memory for best performance. sybase documentations said you can't change page ...
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0answers
6k views

Could Oracle ORA-08103 'object no longer exists' error be caused by size of undo_retention parameter?

Had a once-a-day long running data warehousing procedure that I had written that was failing about 50% of the time. Logs were showing ORA-08103 'object no longer exists'. ORA-12012: error on auto ...
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2answers
924 views

PostgreSQL performance degradation over time on a write intensive db

I have observed a weird situation that over time the performance of a query (a combination of queries explained below) degrades, meaning at the start of testing (for a few minutes) the time of the ...
3
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1answer
486 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 ...
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0answers
698 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], ...
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1answer
2k views

Planning simple CMS: How much relation?

I'm currently in the process of designing the database for a rather minimalistic Content Management System I'm working on alone. It should allow scalability while remaining speed, especially on boxes ...
4
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2answers
1k 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 ...
7
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2answers
5k 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
290 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 ...
4
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1answer
468 views

NuoDB with Amazon S3

I think about developing my new mobile and web app against NuoDB. I believe in their technology. The thing that I care the most is backup and restore in case of data corruption and read / write speed ...
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3answers
423 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 ...
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1answer
4k 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 ...
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1answer
206 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 ...
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2answers
2k 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 ...
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1answer
286 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 ...
2
votes
1answer
347 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, ...
3
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1answer
154 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 ...
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1answer
437 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
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3answers
3k 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 ...
3
votes
2answers
316 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 ...
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1answer
148 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, ...
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3answers
541 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 ...
4
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1answer
340 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 ...
7
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2answers
16k views

Could not continue scan with NOLOCK due to data movement

We run SQL Server 2000 and we get a few of these errors every night. Could not continue scan with NOLOCK due to data movement The query that throws this error is a large complex query that joins ...
5
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1answer
493 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, ...
4
votes
2answers
917 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 ...
5
votes
1answer
709 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, ...
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3answers
14k 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 ...
11
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2answers
1k 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 ...
6
votes
1answer
8k 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 ...
4
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1answer
344 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 ...
4
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2answers
2k 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 ...
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2answers
1k 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 ...
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2answers
678 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 ...