Improving the performance characteristics of a database application or system.

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1answer
43 views

How to increase performance in Cross Database operations?

We currently have a SQL Server 2008R2 being accessed by a legacy ASP application. Among different processes, one of them essentially SELECTs data from one database and INSERTs (or UPDATEs) them into ...
2
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1answer
176 views

High I/O for part of query

I have a large query that I'm trying to tune. I write lots of queries but haven't done a lot of tuning. I've included a screenshot from SQL Sentry Plan Explorer Free (SSPEF): In the above part of ...
2
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1answer
215 views

poor and/or unreliable InnoDB performance

I recognize that there are a ton of posts like this, but after reading up on InnoDB performance problems, nothing I tried has helped. I have a database containing four InnoDB tables. The largest ...
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1answer
53 views

Tuning MySQL query from explain

I am working on a search query in MySQL. I am getting this from explain: Original screenshot These are my indexes: Table definition: Original screenshot Query: SELECT `t`.`id` AS ...
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1answer
75 views

How to speed up query containing concat() in WHERE clause?

In my company we use a commercial software running with mysql 5.5 (MyISAM) that often executes a query of this form: SELECT table1.attrib1 FROM table2, table1 WHERE table2.status = 'Active' ...
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1answer
96 views

Are scripts like sp_BlitzIndex and the others accurate on restored backups?

I am a developer trying to get a better grasp of things. I am wondering if using the scripts from BrentOzar.com will work on restored backups? For example if I have the DBA give a backup of ...
1
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1answer
151 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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1answer
42 views

Identifying root cause of high cpu load

I need to research what caused a high load in our Oracle database some days ago. I wish to see a list of of high-load SQL statements. We don't use any Oracle tools like ADDM or AWR. I tried to ...
0
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1answer
84 views

Scale MySQL trigger for thousands of inserts per seconds

We are using MYSQL database for an Analytics app. I have two table token and token-big (for overview of actual data) both have id(int) unix_starttime(int) unix_endtime(int) details(varchar 256) A row ...
0
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1answer
49 views

Good encryption performance

I'm converting a sql server database to postgresql 9.4. I'm stuck on something that is really really slow. I use copy to bulk insert 200 files of 5000 lines each into 200 tables (one file per table). ...
0
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1answer
38 views

What is exactly a uniform server in a galera cluster setup?

In many manuals about performance tuning and avoid Galera's MySQL cluster limitations they write the below suggestion. It is possible for a slow/overloaded master node to affect performance of ...
2
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0answers
35 views

MySQL memory is keep on increasing , any reason?

On one of our production host MySQL memory is keep on increasing day-by-day. I tried reboot of MySQL instance but still no avail. System has 16Gb of RAM. TOP output top - 13:05:13 up 35 days, ...
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46 views

How to identify whether a log backup or job executing a SP is causing High Page Reads/sec

For one of my servers( SQL server 2008R2) we can continuously witness High Page Reads/sec during business hours say: from 7 AM to 9 PM EST. I kept the counter settings to monitor the same and found ...
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0answers
72 views

Performance of database with transactional data

There are lots of row modifications (several thousands of rows per minute) in our PostgreSQL database that stores transactional data. We have a problem because PostgreSQL runs vacuuming process and ...
2
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0answers
228 views

High Cardinality, Time Series Data.. what DB should I use?

I have a system that I'm building based on ElasticSearch. It works great, except I'm having trouble with one of my facets. I've got about 10 million documents, and each document has 1 to 200 ...
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23 views

Update queries randomly slow on INNODB Mysql

I have been struggling with a slow update query. Have already tried using indexes and other query optimization techniques. I have been using MYSQL database with INNODB engine. The issue is that, ...
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0answers
38 views

DB CPU parameter in AWR - Oracle

What is the significance of DB CPU paramater in Automatic Workload Repository? Say in my case it's always above 100. Does it have benchmark metric as such to say that so and so number is the right ...
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0answers
27 views

Why do Statistic recommendations disappear from DB Tuning Advisor after implementing recommended indexes?

Why is it, when analyzing a query through Database Engine Tuning Advisor, statistic recommendations disappear after some or all of the suggested indexes are implemented? For example, Query X suggests ...
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0answers
99 views

How to speed up for huge tables in SQL select query?

I have the following huge tables. Table_1 with 500000 (0.5m) rows Table_8 with 20000000 (20m) rows Table_13 with 4000000 (4m) rows Table_6 with 500000 (0.5m) rows Table_15 with 200000 (0.2m) rows ...
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36 views

Best ratio for files and file groups for a highly partitioned table

I have a number of tables with exactly 1000 partitions. Each table can be up to 200G with 100M rows and cannot be compressed. Data in partitions distributed quite equally. The SQL Server has 8 ...
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111 views

DB Design: Looking for Performance improvement with a Column used in all SQL Queries

I recently got added to a new ASP .NET Project(A web application) .There were recent performance issues with the application, and I am in a team with their current task to Optimize some slow running ...
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79 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 ...
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72 views

MongoDB read performance

I have an ingestion process which loads data into a specific collection at a very high rate. Some of these documents have to be loaded into another system in batches of 100K . Means as soon as I find ...
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568 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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711 views

What to do with unused RAM on a MySQL database server?

For years I have been running dedicated servers with more or less limited ressources, resulting in unsatisfying performance of the web application (Drupal). Tools like Matthew Montgomery's MySQL ...
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105 views

MySQL query with order by decreased performance

Here is my schema: CREATE TABLE `UserMst` ( `UserID` mediumint(8) unsigned NOT NULL AUTO_INCREMENT, `EMailID` varchar(50) DEFAULT NULL, `UserName` varchar(20) DEFAULT NULL, `FullName` ...
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69 views

performance improvement - left join

How do I rewrite to improve performance of the below query. select S.col1, S.col2, MaxDDate from s_tbl s left join (select col1, MAX(DDate) MaxDDate from F_tbl group by col1 ...
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56 views

Help with Mysql with 100K+ Table

Hi im trying to develop a database design in which its gonna have 100K+ tables residing in it. My major concern here is will Mysql be able to hold that much amount of tables with no performance ...
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706 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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56 views

PostgreSQL query taking a long time

I have a query that is taking hours to run. There is a large table to parse, is there any way to optimise this? with VehData as ( SELECT * from dblink('host=databasesrv port=1234 ...
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101 views

MySql Innodb Database Slow INSERT Query to Remote Server

I have searched thoroughly on how to improve general performance of my database which is hosted on Hostgator. I have mostly come across performance tuning strategies which are catered to only local or ...
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29 views

Trigger copies history table: Will removing index lock options speed up the process?

I have a trigger applied to a table to write inserts and updates to a history table. That history table can grow pretty fast, and we want to see, if we can speed up insert operation a bit. The values ...
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31 views

Informatica is causing Convert_implicit in SQL Server 2008

In our project a datafile is loaded into SQLServer using Informatica. The source column is defined in Informatica as UniChar.60 The target column in SQL Server is defined as varchar(60) But when the ...
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65 views

Tunning MySQL Variables

we have a dedicated mysql server with 10 CPU and 32G of memory After doing some readings came up with those configs : # This was formally known as [safe_mysqld]. Both versions are currently parsed. ...
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54 views

Which of sys.dm_exec_query_stats columns should I pay most attention?

I'm trying to tune my database and currently staring into sys.dm_exec_query_stats (with actual queries): SELECT SqlText.text, * from sys.dm_exec_query_stats CROSS APPLY ...
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17 views

MySQL 5.5 only use 1 thread and 30% cpu

i have a big issue, every day i need to update or insert like 3.3 milion rows, i have trying to do what ever i can but it still only run like 605 query/s i use VirtualBox so my setup are testing on 1, ...
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82 views

Performance issue after reorganizing table in MYSQL

There is MYSQL(5.6.22-log Community Edition) database environment which has databases size varies between 1-40GB and using INNODB storage engine, it's serves for the several number of OLTP based ...
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136 views

PostgreSQL Performance - Many Large Databases

I run an internal (development) database server containing 25 databases each ~71GB in size. There are usually between 50 and 100 active connections at any given time. What can I do to help improve ...
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64 views

Query plan reads vs statistics io reads

I have a very strange problem. When I run a query with SET STATISTICS IO ON, it shows that I had a total of 183 reads. But when I look at the query plan dmv it shows I did 555,132 reads. I cleared the ...
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122 views

Is my SQL Job causing the High Disk usage?

I have a concern regarding High Average disk queue length for one of my server with below configuration: Version: SQL 2005 with SP3, standard edition. windows: version 2003 r2 SP2 No Processors= 4 ...
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56 views

Intermittent MySQL 5.17 issues - extremely slow queries

I am experiencing major issues with intermittent mySQL issues. To give some background the website runs optimally for the majority of the time, however 3-4 times a day queries that should take a split ...
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0answers
105 views

PostgreSQL buffer page size limitations - rebuild with larger size?

We just ran into a limit on indexing due to the 'index size cannot be more than 1/3 of page size (2712)' error. This indicates the buffer page size is 8192 (8k). This seems awfully small during the ...
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0answers
120 views

Window function sorting performance

For background, I am on an instance of SQL Server 2012 Enterprise Edition. I have three tables that join on the same set of three keys - all of them are INT. All tables have their keys clustered in ...
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73 views

is there any limit of MySQL status variable value?

As we know MySQL status variable is a counter variable since the service start. MySQL service in my DB server restart every week (on sunday). Below is my observation since last few week: Suddenly ...
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0answers
48 views

How to handle too many instances of multiple tables?

If there is a table accessed by multiple DB threads ( for example 100) at a time then how many instances of that table will be opened? If I run show open tables and see that in_use column value of a ...
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161 views

MySQL: What should I do if too many tables opened during peak hours?

In Peak hours: When I run below statement, I found around 100 tables out of 250 have opened. show open tables where in_use>0; There are around 10 tables for which in_use value are >50. Storage ...
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125 views

Big Mysql table optimization

I have a table that I use to cache google translate API answers. Table structure is orig_string and group are indexes Now it has more that 1million rows with 35000 distinct values in group field. ...
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180 views

Remote scan in OpenXMl

I'm looking for some advice on OPENXML. Specifically, the performance. I am seeing very slow performance on a very small piece of XML. Something about this is causing a Remote Scan. Any ideas on how ...
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0answers
213 views

MySQl: slow query is not using index in joining

Below is the configuration of my DB server: Apache version : Apache/2.2.22 (Win32) mod_ssl/2.2.22 OpenSSL/0.9.8 PHP version : 5.3.13 MySQL version : mysqlnd 5.1.11 Windows Server 2008 Standard ...
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129 views

InnoDB tuning with 1G of ram limit

I am trying to calculate variable moving averages crossover with variable dates. That is: I want to prompt the user for 3 values and 1 option. The input is through a web front end so I can build/edit ...