Improving the performance characteristics of a database application or system.

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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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1answer
43 views

Postgresql performance issues when issuing many small inserts and updates one at a time

I have a production web server with postgresql database. My server gets data from another server every hour on the hour. The other server wakes up and sends many requests to my server, each result in ...
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1answer
35 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 ...
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1answer
45 views

Why MySQL SELECT performance depends on table size? [closed]

I've got two identical tables with the following structure: CREATE TABLE words ( id bigint(20) NOT NULL, `text` int(11) NOT NULL, w1 int(11) NOT NULL, w2 int(11) NOT NULL, w3 int(11) NOT ...
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1answer
35 views

High Page Faults/sec low Page Reads/sec

I currently have Page Faults/sec avergaing 1269 while my Page Reads/sec is averaging 0.3. I am just trying to interpret what this means. I assume I am getting lots of soft page faults in this case ...
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13 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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2answers
80 views

How can I monitor my server’s status before changing the “Cost threshold for parallelism” settings

Our production server is running SQL Server 2008 SP3. I’ve read a post on “cost threshold for parallelism” - ...
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33 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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41 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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1answer
62 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 ...
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1answer
25 views

Uniq join 3 tables with relationship table not uniq

I am using Postgres. I have 3 tables: table_1 id table_1_2 table_1_id, table_2_id table_2 id The problem is the relationship table table_1_2 is not uniq. I.e., table_1_2 will have the ...
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57 views

High performance SQL Server - Poweredge R730xd [closed]

Last year I wanted to move our critical SQL Server solution from Virtual to physical. I liked the Poweredge R720 with it's 2 RAID controllers and favoured filling it with 2.5" Samsung EVO SSDs - not ...
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1answer
71 views

How to speed up mysql query against a 204 million record table

For some reason my server has been finicky lately and for the life of me I can't figure out why. I monitor the memory usage by running shell# watch -n 5 free -m without running any activities ...
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14 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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2answers
280 views

Optimizing queries for 25+ million rows

I am using MS SQL, and I have to run several queries on the same table on different criteria. At first I ran each query on the original table although they all share some filtering (i.e Date, status). ...
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1answer
68 views

Optimizing query for large number of rows in mysql

I have the following database table in MySQL : and is running the following query SELECT `scratch_tickets`.`id` AS ticket_id, `scratch_tickets`.`created_at`, `scratch_tickets`.`prize_type`, ...
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1answer
32 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). ...
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1answer
73 views

Extremely long startup time for MongoDB server

I have a MongoDB Server with just over 2 million documents in one collection. Individual documents can contain large amounts of data (some are several megabytes each) but none of that data is in ...
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1answer
131 views

Large MySQL operations slowing down SELECT queries on unrelated tables

On a fairly busy SQL server, we sometimes need to do large index-building operations (after importing ~6GB tables). The indexes are built using the more efficient "Repair by sorting" method, rather ...
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2answers
101 views

What perfmon counters should I use to get the fastest restore possible on an idle system?

I have a development VM running Windows 2012-R2 and Sql Server 2014. I have one disk from a SAN holding the OS and SQL. My backup file is stored locally on the disk. I want to restore database as ...
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32 views

SQL Server 2012: query to see queries that are consuming more resources [duplicate]

I'm trying to find/build a query to show me those queries that are consuming more resources in SQL Server so that I can optimize them or at least have a statistical idea of what is really happening. ...
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57 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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72 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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1answer
45 views

Can I throttle individual databases instances on one SQL Server 2005 box

I am running a very old server that has a database that is being permanently retired within 14 months. My company will not invest anymore in hardware or software for this system as we are moving to a ...
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1answer
48 views

maximum allocate RAM for MS SQL Server

I have MS SQL Server with different size of RAM. So I would like to control the values which are set for the RAM. Somewhere I read a 'rule' to calculate the maximum of RAM. These SQL Server are only ...
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1answer
40 views

How bigger page size effect at performance?

I know in case of Cluster index bigger page size improve peformance for range and multipoint query. Does bigger page size can effect to degrade performance when we have non cluster index .Because ...
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45 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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2answers
131 views

How to auto assign ordinal ranking in mysql with as minimal queries for new rows?

+----+---------+---------+-----------------+ | id | view_id | user_id | ordinal_ranking | +----+---------+---------+-----------------+ | 1 | 10 | 1 | 1 | | 2 | 10 | ...
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1answer
63 views

Does SQL Server redistribute data after adding an additional data file?

Imagine a database about 30GB in size using 3 data files on the same disk. Someone told me to have one data file per processor implemented to get full performance on all cpus. So if I now add three ...
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1answer
171 views

Table with clustered Index consuming max memory causing low PLE alerts

For one of my server with below configuration i am continuously receiving alerts for low PLE which ranges between 20- 400 and an average of 90-100 in a day: Server: SQL server 2008R2 Databases : ...
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1answer
31 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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1answer
103 views

SQL aggregate function performance in a table with many records that is well-indexed

My question is about 3 tables that stores data of a single entity, and there is a report generation feature that refers these tables and calculate COUNT and AVG information. There are three tables: ...
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2answers
364 views

use an Index correctly to optimize queries

I have an SQL database with millions of records and when I'm querying the data like select * from ActCosts where ScenarioID= 456 The tables has 1,323,718 rows and it gives me like 50,000+ rows ...
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43 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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25 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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1answer
82 views

Optimizing intersect query in MySQL

I'm facing a performances problem in our MariaDB server. We have a table linking users to pages, a user belongs to 1+ pages. I have a page that have users and I want to get the 10 best pages based ...
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1answer
81 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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2answers
87 views

Using Database Engine Tuning Advisor in production

I have a SQL Server 2008R2 OLTP database which is experiencing performance issues during work hours. I would like to run Database Engine Tuning Advisor on this instance but I don't know how it will ...
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33 views

Why does retrieving fewer rows take longer? [duplicate]

I have a view that (left outer) joins multiple recursive CTEs. There are about 10k rows. The results of running SELECT * FROM MyView ORDER BY MyPrimaryKey, with statistics time and io on: SQL Server ...
3
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1answer
73 views

reporting space consumption to files in filegroup - how to reverse-engineer the algorithm spreading data across files

I would like to know how to calculate the distribution of data consumed per file in a filegroup, back to the index (HEAP, CLUSTERED, NONCLUSTERED) storing it. My intention is to define which I/O goes ...
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1answer
271 views

OS Paging too high in sql server

For one of my servers with below configuration: Total RAM: 32 GB CPU: 8 Max Server Mem: 22.5 GB Min Server:: 4 GB Edition: Enterprise Edition with 2k8R2 installed on SP3 ...
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1answer
107 views

Select two aggregate functions on the same column using different criteria - performance

Dear stack exchange users, first question here. The database in question is a service database where a user hires a service. Now I would like to show the person that was hired an overview of how many ...
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3answers
2k views

Do I need to reindex mysql table after bulk delete?

I have a table in MySQL with a lot of INSERT and SELECT at every second. And there is a bulk delete of some older data once in a day. Do I need to reindex the table after delete? I want to increase ...
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2answers
121 views

Do I need to reindex my table in mysql after delete?

I have a table in mysql with a lot of INSERT and SELECT at every second. And there is a bulk delete of some older data once in a day. Do I need to reindex the table after delete? I want to increase ...
0
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1answer
354 views

Query optimization for multiple joins postgres

ER Diagram Brief description The database to be used is postgres. The database might contain upto 2 million AccountHolder records. Since the AccountHolder table is accessed and updated frequently ...
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41 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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69 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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2answers
2k views

Hyperthreading & MySQL InnoDB Thread Concurrency Performance

I have a dedicated DB Server with the following specs" Ubuntu 12.04 LTS Server Intel(R) Xeon(R) CPU X5670 @ 2.93GHz 12 Cores MySQL 5.5.29 64 GB RAM RAID10 We are currently doing Hyperthreading ...
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1answer
2k views

SQL SERVER – Find Most Expensive Queries

I am running the following script to find most expensive queries. However I want to narrow it down to only queries ran on Saturday 18th October 2014 Is there any way to do this? SELECT TOP 50 ...
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1answer
150 views

What do these pstart and pstop values mean?

I'm attempting to tune a query and I want to be able to tell if partition pruning is happening. On one part of the query, the I'm getting a Pstart and Pstop value = "KEY": | Id | Operation ...