Improving the performance characteristics of a database application or system.

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2
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82 views

Best procedure to measure query optimization effects?

I could not find valuable answers or explanations to the following question: How should a procedure to test query improvements effects look like? Using SSMS I am not absolutely sure about the steps. ...
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50 views

SQL Server Trace Flag 834 on VMware

It's recomended to enable trace flag 834 to use large-page on buffer pool for SQL Server running on VMware? The tuning options kb of Microsoft (https://support.microsoft.com/en-us/kb/920093) don't ...
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74 views

PAGEIOLATCH_SH and WRITELOG waits

We have a slow overnight process which I was asked to look at with the top waits being PAGEIOLATCH_SH and WRITELOG I have been collecting information from sys.dm_io_virtual_file_stats and can see ...
2
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74 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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52 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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82 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 ...
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280 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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838 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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53 views

sys.dm_db_index_physical_stats slow on first run after rebuilding indexes

I have a 10GB database in SQL Server 2016 RC1 on Windows Server 2012 R2 where I just performed many insert and delete operations. Afterwards, I ran: EXEC sp_MSforeachtable @command1="SET ...
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25 views

MYSQL Created_tmp_disk_tables value increases on almost every query

Should I be concerned that tmp_disk_table # is growing even when I run a simple query like elect id from table with 1000 rows where id is an integer and is primary key) I've fiddled with other ...
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101 views

Basic PostgreSQL 9.x Performance Optimization Strategies for Reads/Analysis

Postgres comes, out of the box, configured as a general purpose database for both OLTP and OLAP types of loads. My need is to do use Postgres, in this case, purely as an OLAP running aggregate queries ...
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97 views

MySQL 5.6 Performance Tuning Issue

I have read and try lots of things about MySQL optimization and tuning. I tried most of them one by one according to our needs but nearly I got nothing. I am doing my test using some simulation ...
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98 views

How Can I Increase Performance of This MERGE Statement?

I have a INSERT INTO/MERGE statement that is part of a stored procedure that needs to be really efficient. The execution plan shows that 90% of the procedure is due to the following statement shown ...
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180 views

Mongodb Huge Number of Open Connections and Write Locks

We are seeing around 800 open connections to our Mongodb. To clarify our issue: We have 5 different clients who write the data into Mongodb. Each of these clients - write four different type of ...
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54 views

Mariadb improve performance while import dumpfile

I have a dumpfile with millions data inside. I want to decrease time because I waited too long. I imported 10 million data (3 GB) and I waited 1:30 hours. I will import nearly 100 million data (30 GB) ...
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84 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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234 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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33 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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225 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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136 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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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 ...
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80 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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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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954 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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116 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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83 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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248 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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57 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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13 views

Reporting Services Maintenance and Performance Best Practices

I'm simply looking for what most folks do to keep their SSRS servers in top shape. Beyond performing backups of the databases, symmetric key, custom extensions, configuration files, IIS settings, ...
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21 views

Example Database for tunning

I've been searching for so long and I've still have not found what I'm looking for ,is there any database or similar resource that people uses for tuning a database, or optimize queries?. I would be ...
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9 views

PostgreSQL 8.2 giving inconsistant exexcution times

We are using PostgreSQL 8.2 and we are seeing a very strange behavior when we run queries in multiple threads. We are running the same query with 5 simultaneous threads for a period of 1 hour. When ...
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18 views

How can I improve this nested postgresql query?

I have a mildly complex query that is having rather poor performance: UPDATE web_pages SET state = 'fetching' WHERE web_pages.id = ( SELECT web_pages.id FROM ...
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16 views

What is Fastest way to export 400m rows DB2 table

I want to export table data in a file to load it in memcached. This table has 400m rows. Right now I am running db2 export command and it takes 1hr 10min. This table has 8 columns, 1 int, 2 timestamp ...
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36 views

Improving slow queries, slow query log attached

I am running MariaDB under Cpanel and hosting Wordpress websites. My slow query log has reached ~400MB in size, and I would like to know how to eliminate the DB issues. Link to the slow query log. ...
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66 views

Retrieving the latest forecast

I am writing an application which stores weather forecasts for different cities, and each day there is a new forecast for each city. I want to be able to provide daily forecasts, and also the latest ...
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45 views

Reducing the time when retrieving all records from large databases

I have to retrieve most of the records from large table, I'm talking about approximately 3 millions rows. I'm even using this site as a guide for tuning the database. It is not enough, it takes an ...
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46 views

Why dropping TokuDB partition so slow

I have defined a simple time series table partitioned by UNIX timestamp (into 32 days). I then loaded ~17K entries, which were distributed among 8 partitions. There were at most 2880 rows in any ...
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899 views

MySQL 5.7 InnoDB is extremely slow on spatial data compared to MySQL 5.6

I have a table area which contains ~300,000 rows. It is defined as follows: CREATE TABLE `area` ( `area_id` bigint(20) NOT NULL AUTO_INCREMENT, `boundary` geometry NOT NULL, `name` varchar(255) ...
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19 views

server response is getting slow day by day

MySQL server 5.5 > running in Linux Box is getting slow. MySQL server is being used by Java Web application, please help me to figure out the problem.
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51 views

Optimizing DB for performance by archiving/partitioning

I have a table in my Database which would be loaded with huge amounts of data each day. These are basically status of the orders customers has placed. The UI in my application which calls the DB for ...
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31 views

Minimum Oracle table size making IOT advisable?

I have inherited an IOT that doesn't seem to merit it because: only 25k rows fairly pure join table, non-index fields rarely queried total index width only ~125 bytes total row width only ~160 bytes ...
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132 views

Why my mariadb slow when I select all from empty table?

I try to find why my database slow when I select all table . That's empty table... MariaDB [kohadata]> select count(*) from biblio; +----------+ | count(*) | +----------+ | 0 | +----------+ ...
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61 views

SQL Server File Latency

I've a Database which is in SQL Server 2012. For the last couple of weeks it's very slow and some times not responding to the queries. So I checked the read/write latency and the result is - Read ...
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98 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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159 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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165 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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70 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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29 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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115 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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285 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 ...