An evaluation of whether a system works well enough to be fit for purpose. Normally performance refers to the speed with which a system completes an operation or set of operations over time.

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174 views

Most efficient way to sort data fields into SQL

I'm trying to decide on the most efficient way to sort various data values. Here's how the data arrives: Device X sends a text string "name=value&name2=value&name=value" On arrival that ...
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680 views

Efficiently retrieve big amount of data based on date range

Table EVENTS TimeStamp |O.Name |Location |Source | 2008-11-12 |Pretorian|Európe |England | 2009-12-24 |Lex Rosa |Európe |Italy | 2010-01-01 |Nasdaq |USA |Whasington | ...
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157 views

Why is this table structure so slow to CRUD?

I have a table that I am using for queuing emails. Unfortunately, adding to or reading from this table becomes horrendously slow after adding about 50 records. -- Table "mail_queue" DDL CREATE TABLE ...
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1k views

Oracle 10g - Sudden change in execution time for specific query

After the DBAs fiddled with some parameters in our Oracle 10g Production Environment, most queries became a little faster. But a single query (a quite complex one) became dramaticaly slower - it went ...
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503 views

Finding the bottleneck by analyzing Munin graphs

We’ve been experiencing some issues with our database server during peak hours. In our Nginx error-log we can see that a lot of requests get timed out. The requests are also very slow. We have had ...
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107 views

Long disk queue when no traffic

I got dedicated disk (RAID 10 - 4 SAS disks) for Postgres. I am bit worried as recently, I see under Windows Resource Manager disk queues like 3+ in the mornings (low traffic hours), like every 30-60 ...
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34 views

Slow application performance

We are experiencing slow application performance on a couple of apps. We are on SQL Server 2012 Standard Edition 64 GB. This is installed on a Windows 2012 R2 server. The database is without mirroring ...
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21 views

How can I restore a MySQL dump faster on Windows?

I am restoring some InnoDB and MyISAM .sql files that are on the order of GBs (ranging from 1 GB to ~ 10GBs) and they are taking a day or longer to restore. The command I am using currently is: use ...
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13 views

Reliability of MySQL Events Table

Is there any limitation of usage of MySQL Events table. Let us say i will have 10K of entries which will be executed across 3k schemas. They all are not same time but at-least 3K events will be ...
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41 views

MySQL performance issue after migration

I have a MySQL performance issue with a brand new server, and am somewhat of a beginner as a database administrator (I'm mostly a general-purpose Linux sysadmin). I'm looking for pointers where to ...
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15 views

MySQL 5.6.18 got signal 11

My MySQL Server 5.6.18 got signal 11 today very randomly. Has not happened before. This is the stack trace : stack_bottom = 7fdb9bcb1e0f thread_stack 0x40000 ...
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51 views

How to optimize this query on oracle?

I have built this query in oracle to get some data i need from the two tables below. At SELECT REGEXP_REPLACE i get the IN_01 as input parameters from the user and it can be much bigger list than ...
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26 views

Linked Server to Oracle seems to be slow

we have a linked server between a SQL Server 2008 R2 instance and an Oracle 11.1.0.7 instance using OraOLEDB.Oracle Provider. The enabled options for provider are: Dynamic parameter Nested queries ...
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35 views

Database calculations question

I am creating a MySQL database that is going to be used to store a lot of timestamps. There are currently 6 timestamp fields that data can be entered for one row. I am utilizing timestampdiff to ...
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15 views

calling multiple procedures from my application Vs calling procedures inside another procedure

I have a scenario of saving user details into my database(MySQL 5.1); i have three tables for saving user details; user_data,user_contact,user_address, so if i insert one user data i have to check for ...
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13 views

T-SQL script to analyse recent changes in SQL Server configuration?

Last week suddenly one of our VMs running SQL Server slowed down considerably and its performance dropped to the level where some of us cannot work on it any more. Just to give you an idea about the ...
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27 views

MySQL performance affected by calling functions from inside procedures?

this is the very first question I post, so please bear with me ... When working on a project, I tried to get the LAST_INSERT_ID for a table, by invoking it from inside a procedure right after an ...
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18 views

Sudden performance gain when performing mysql queries twice, lacking on live host

I was having performance problems and could improve it down to 14 seconds roughly per execution (if you see any way to improve that further, I would be really thankful). Which, is still very slow. ...
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16 views

Correlating Disk Latency on Application side Vs. EMC SAN

Our OLTP databases have encountered several I/O issues. During those events: Avg disk sec read on the data file was 0.2 second or higher We found windows eventlog entries stating: "SQL Server has ...
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344 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

Need some advice on db layout

I have some data that gets exported from a different system that I want to suck into mysql for some analysis. Currently, the export consists of 2 files, essentially file1 is the list of transactions ...
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25 views

Does extending datafiles affect performance

We have an Oracle 10.2.0.3.0 on Windows 2003 Server which is scheduled for upgrade within the next six months. One tablespace is about 2TB in size with over 250 data files. Some of these were ...
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19 views

Performance issue for daily calculations - Sybase Adaptive Server

I need an advice from the community, there is no wrong answer I'd like to have as many advice that I can ! I manage a process that does every day a lot of financial calculations and they are ...
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47 views

MySQL query hanging while copying to tmp table

I have a query that ran in 10+ seconds last week, but now is hanging even after 10 minutes. I'm running this in a test environment so the data hasn't changed much and I am baffled at what could be ...
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25 views

Any risks to pure inserts + delete duplicates, instead of insert/ update for SQL Server?

I saw a related question but it was more of the how vs. the why. I'm wondering in SQL Server why one would attempt an "insert/ update" with incoming data ... instead of just running pure inserts ... ...
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41 views

MySQL database hangs but less CPU

I create an application for 30 concurrent users using C# and InnoDB of MySQL (mysql-5.1.35). The size of database is more than 100M lines (~20GB). Most of data is come from 7 active table (2M ...
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38 views

How to tune a sql server for a specific process in particular?

I have a specific process that I am want to tune for in a sql server DEV server. The DEV server and the LIVE server are equal, just the DEV has less memory. Both LIVE and DEV read data from the same ...
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32 views

Increasing system load due to multiple inserts every millisecond

In my project I need to do multiple database inserts every millisecond and thus Postgres takes huge amount of CPU. I need to find a way to reduce CPU load as I need to process about millions of rows. ...
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85 views

Performance: Postgres (Read-Committed) vs MySQL (Read-Uncommitted)

I have a workload that involves very frequent writes and reads. It is very performance sensitive, but not accuracy-sensitive. Hence, to maximize performance and minimize locking-delays, my plan was to ...
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49 views

Improve performance of count(*) with two exists

I need some help improve performance of this query that runs in Postgresql 9.4 at Amazon RDS: SELECT count(*) AS total FROM people WHERE EXISTS ( SELECT 1 FROM person_values WHERE ...
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0answers
29 views

What is the fastest way to do a REGEXP find and Replace in MySQL database?

I have a table with 700,000 entries and I need to check each entry for 1,000,000 words and then replace the word if found from hello to #~hello~#. Words can occur multiple times in an entry and need ...
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6 views

Reason of poor performance of ANSI joins in Oracle 9i

Please before flagging as duplicate, read the last paragraphs. In an Oracle 9i database this query runs in 0.18 seconds: select count(*) from dba_synonyms s,dba_objects t where ...
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36 views

ORM and performance for SQL Servers

In a past SQLBits, one of the speakers went into some detail about ORM software's effect on SQL Server performance. The example the speaker was referring to was one in which the application was ...
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0answers
36 views

Non-structured Query performs better than on clustered, hash-clustered and indexed?

I am using the following query as a base line on some unstructured data (no indexes, no clusters etc) and the query is performing better on the unstrutured data than when I add indexes to the join ...
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74 views

Slow mysql query full text search tag database

In the database are ~700k images. Each image has its own tag(s). I want to be able to search images by the tags with a full text search query. The query does exactly what I want but it's very slow. ...
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30 views

Query performance tuning with joins on views with large data

I've this query in oracle. This is basically the query of a BA report which I'm trying to tune. SELECT DIM_PROJECT_OL.PROGRAM_ID, DIM_ANALYTIC_STRUCT_ACCOUNT_OL.STRUCTURE_ID, ...
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0answers
87 views

How come MySQL LIKE is faster then FULLTEXT?

So, I was trying to optimize my MySQL queries, but found out that i'm actually doing this wrong. I've changed my query from using SELECT * FROM test WHERE tst_title LIKE '1%' To: SELECT * FROM ...
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0answers
40 views

Identifying high load sql

We had an oracle outage some days ago. We have inbetween awr tools. I genarated awrrpt report but dont see anything suspicious. Which report should I generate to see sql, which caused very high cpu ...
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124 views

Tuning MySQL with InnoDB engine for my application

I've read through a lot of answers, and I realize this is mostly application specific, so I wanted to give some background as to what I'm doing with the database and hopefully get some tips on tuning ...
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0answers
34 views

optimizing a wild card search query in mysql

I want to have a search option in my game portal site. (right now i'm using google's in site search) I want a user to search to enter a search term and need my query to search the search term in the ...
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0answers
46 views

Improving SELECT queries involving multiple joins

I have the following query: SELECT event.* FROM event LEFT OUTER JOIN invalid ON invalid.event_id LIKE event.id AND invalid.userid LIKE '<userID>' LEFT OUTER JOIN owner ON owner.id ...
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0answers
25 views

Data transfer in sql server 2008

I have following requirement In SQL server 2008,Trying to implement in stored procedure source table T with 100000 records need to be insert into destination table T1.A Job will be schedule for this ...
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0answers
64 views

Oracle Performance on 2 servers

I have the same database on two different servers(production and test) with major differences in query time as follows: Query1: SELECT distinct dms_get_FAST_serverpath(d.id) full_name FROM ...
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0answers
138 views

Tuning a Postgres INSERT only database

I am designing a database which will have many inserts and selects, but no updates. Are there any considerations to take (in order to have high query performance) while knowing no tuple updates will ...
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0answers
17 views

ASE 12.5 - Local variable in stored proc - performance issues

I've been told many times that using a local variable inside a stored procedure (ASE 12.5) will degrade performance because it prevents indexes from being utilized. I've searched allover for more ...
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0answers
95 views

Load Large data set SSIS AWS EBS

We have configuration of SQL 2012 std edition hosted in Amazon cloud that has data disk of 3 TB, Index disk of 3 TB, Log disk of 500 gb all raid 0 stripped. Am trying to load a table that has 8 ...
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129 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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0answers
26 views

DB space vs query complexity tradeoff

I have a dilemma - Right now I have a query that I do constantly - joining 5 tables on different columns, calculate stuff per row, distinct on that, and do that with offset and limit (pagination). I ...
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0answers
31 views

PostgreSQL analyze only parent table only

I am moving data from a few billion records table to newly created partitions. I am inserting into the child table directly and deleting from the main table with filters on the appropriate columns in ...
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0answers
318 views

mysql eating RAM without queries?

Somehow MySQL eats up 50% of my RAM on the server being used. I checked and there are no queries, show full processlist is empty. I restarted the mysqld and within a couple of minutes the RAM usage ...