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

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1answer
403 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, ...
2
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1answer
218 views

Maintenance plan using external tool to execute query and stored procedures giving off no results

My situation is as follows: I am using a third party tool (VisualCron) to run stored procedures and sql queries on several database servers. The stored procedures are from http://ola.hallengren.com/ ...
2
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1answer
664 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, ...
2
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1answer
180 views

Reading a SQL Server Execution plan

I am very new to any type of tuning but have been learning more.. One of my specific databases one of the problems identified with slow queries are a number of Implicit conversions. It is my ...
2
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1answer
552 views

What are these files in MongoDB?

I was looking into my server and I found this: [root@host ~]# cd /var/lib/mongo/journal/ [root@host journal]# ls -lh total 3.1G -rw-------. 1 mongod mongod 1.0G Apr 7 01:18 j._0 -rw-------. 1 mongod ...
2
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1answer
462 views

Getting the most out of SQL Server with a million rows a day [closed]

I have a windows service that is inserting 1000 rows at 1 minute intervals to a SQL Server 2008 Standard database table that looks like: id, datetime, key_id, value key_id is a foreign key to ...
2
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0answers
29 views

Tuning Issue / Temporary Tables

I've got a MySQL database (MyISAM) that handles a lot of read/writes and uses temporary tables quite frequently. Recently it's started having massive load spikes at peak load, and noticed that there ...
2
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1answer
353 views

Postgres query plans and tuning parameters

I have a query for which the explain plan indicates that the cost for using a seq scan is lower than the cost for using an index that I have set up. However the actual time for the query is 20 times ...
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0answers
839 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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3answers
200 views

MySQL database uses too much CPU

I have a MySQL database which uses too much CPU. I am actually performing benchmarking to the web servers which queries the database. Right now the database is being the bottleneck, it uses too much ...
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2answers
901 views

Very high load avg for MySQL database [closed]

I have a backend server which response to my clients app, it has more than 20k~25k hit per second and this make my server load average very high, I believe that my MySQL config is not appropriate. In ...
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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
3k 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 ...
1
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1answer
159 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, ...
1
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1answer
55 views

Does InnoDB Log Files take RAM space or Disk Space

When I set InnoDB Log File size to 512M, does it take the space (512M * 2) from RAM or the SSD Disk space? When I explored, I can see that the log files are located inside /var/lib/mysql folder. So ...
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1answer
233 views

Postgres: my “data/backup” directory is way too large

In my postgres 9.3 data directory, there exists a subdir called "backup" that is 6.1G compared to my pg_xlog which is only 130M. I understand that pg_xlog is the WAL logs, so what is in the backup? ...
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2answers
4k 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 ...
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1answer
4k 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 ...
1
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1answer
2k 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 ...
1
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1answer
544 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 ...
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2answers
746 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 ...
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0answers
21 views

Several Data Importation Illogical Latency in MySQL [closed]

I am used to importing a 4GB of data from an .sql file towards a testing server (hardware). I tweaked the database to speed up inserts, and, so far, the script takes 6 hours, more or less. We were ...
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0answers
59 views

Tuning MySQL MyISAM for large joined updates

I have a database with two tables that I would consider small. I need to update values on the larger of the two tables (1,100,000 rows, 75M MYD, 120M MYI) from the join of the two tables. The smaller ...
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1answer
55 views

75% of RAM for Innodb_buffer_pool size

I have read many documentation including percona and MariaDB documentation where they recommend setting innodb_buffer_pool_size to 70-80% of RAM. My question is, is that total RAM or available RAM? ...
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1answer
148 views

How do i increase the total MyISAM indexes?

I have just made a check for my server with mysqltuner. -------- Storage Engine Statistics ------------------------------------------- [--] Status: +Archive -BDB +Federated +InnoDB -ISAM -NDBCluster ...
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0answers
135 views

Tuning MySQL On Azure Windows Server Setup

I have a MySQL 5.5 running on Azure VM Windows Server 2012. Once per second the log db gets about 2K inserts through LOAD DATA INFILE... once a day I need to run stats and when the stats are crunching ...
1
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1answer
266 views

Tuning Mysql and Monitoring

I would like to know if anybody can point me towards a tool/way for MySQL database tuning. Actually the tuning of my.cnf is like below: My database engine is MyISAM | Mysql 5.1.73 key_buffer = ...
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0answers
719 views

Optimization Tips For MYSQL Tuner/Primer

So I have a site that has a crap ton of traffic. I see a decent amount of latency when the site has over 1,000 active visitors on it. I have new relic installed and it seems Im only using 10% of the ...
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1answer
170 views

Please suggest my.cnf configuration based upon mysqltuner findings

I have been facing a lot of slow browsing on my site nerdeky.com. My server administrator suggested me to use mysqltuner.pl to find and tune my databases. Can anyone select me what should be the good ...
1
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1answer
200 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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0answers
8k 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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0answers
294 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 ...
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3answers
671 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 ...
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3answers
480 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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4answers
2k views

What can cause Reads to slow down on SQL Server 2008R2?

Our primary DB is 15GB in size. The server has 16GB of RAM. We are using the simple recovery model. Lately we've noticed that our custom apps lookups - just basic reads with adhoc SQL statements - ...
0
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2answers
964 views

What is the default size of text field in Postgres?

In the official documentation (http://www.postgresql.org/docs/9.1/static/datatype-character.html), it states text field is variable unlimited length. I wonder what is the default size of this field ...
0
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1answer
82 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 ...
0
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2answers
397 views

Need Help maintaining multiple databases for a multi-tenant application?

i need some information about multiple databases for a multi-tenant application ? I am working on a project in which we are maintaining separate database for every company? The Companies Database ...
0
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1answer
1k views

SQL Server 2012 Tuning process exited unexpectedly. DTAEngine

I am using Windows Server 2012 x64 and SQL Server 2012. I am running the Database Tuning Advisor with these settings : Advisor plan cache. Database workload master. Check my database all the ...
0
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2answers
4k views

Database partitioning - Horizontal and Vertical sharding - Difference between Normalization and Row Splitting?

I am trying to grasp the different concepts of Database Partitioning and this is what I understood of it: Horizontal Partitioning/Sharding: Splitting a table into different tables that will contain a ...
0
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1answer
2k views

How to measure a perfomance of SQL Server database? [closed]

I have the task to improve the performance of a SQL Server 2012 database (one of 4 in an instance) by 60% confirmed by corresponding statistics. So, I need to measure "performance" of the RDBMS ...
0
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1answer
42 views

Feasibility of Automated and Continuous Performance Tuning in the future [closed]

First a quick background: I'm a software developer, not a DBA and have been developing for more than 10 years. Recently I had to optimize a stored procedure and had to run execution plans, ...
0
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1answer
36 views

Big Size Database and increasing number of users [closed]

Me and my colleagues are using quite big size normalized database. Basically it's used for warehouse management and daily minimum 100 of the user perform data manipulation operations. 80% of the ...
0
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1answer
289 views

Large sequence cache in Oracle

There was a situation of 108,368,168 executions along with 7,373s elapsed time for "update seq$ set increment$=:........" statement while loading massive(i.e. populating million rows) data in the ...
0
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1answer
41 views

Effects of monolothic databases on performance and security?

Please note: although I'm specifically calling out MySQL here, I would also appreciate/entertain generic answers that apply to all/most relational systems. As a developer I don't see the design ...
0
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1answer
70 views

Access and filter in oracle plan

I came to a execution plan where oracle choose to access the index but instead of using the columns as predicate it only filter by them. My question is what are the reasons that can cause that(all ...
0
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3answers
351 views

Large database - too much time spent opening and closing tables

I have a MySQL server (5.5.31) with 450 databases of some 200 tables each. (Yes, 90,000 tables) When we're under high load, there's over 100 concurrent queries, of which 70% are either opening or ...
0
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1answer
4k views

Oracle 11g Enterprise downgrade to Standard One

I'm checking possibilty of downgrade Oracle 11g from Enterpise Edition to Standard One edition. I've cross-checked edition comparison with select name from dba_feature_usage_statistics where ...
0
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1answer
36 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 ...
0
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1answer
67 views

Creating a flexible table containing prices and periodes

I'm creating a system of availability for rooms and with a calendar according to the days, with every day have it's own price. Room Type | 01 | 02 | 03 | 04 | 05 | ... | 31 | ...