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.

learn more… | top users | synonyms

1
vote
1answer
50 views

What is the best option to easily fix fragmented heap indexes?

I have SQL Server 2008 R2 SP2 and also SQL Server 2012 SP2 on these servers. I have a database in which there is a lot of heap indexes which are more than 90% fragmented. What is the best option ...
2
votes
0answers
57 views

No significant performance increase after migrating from SQL Server 2005 32bit 4 Cores 4 GB RAM to SQL Server 2012 64bit 4 Cores 32 GB RAM [on hold]

We run regularly a series of data analysis scripts on one of our databases. The MDF File of the database is several gigabytes big, the scripts perform not only selects, but also inserts, updates and ...
11
votes
1answer
6k views

Index optimization with dates

I have a large table of objects (15M+ row) in PostgreSQL 9.0.8, for which I want to query for outdated field. I want to divide the query by millions, for scalability & concurrency purposes, and I ...
2
votes
1answer
134 views

Update taking too long

I am updating a table with 250 million rows in SQL Server, and it's been running for 4.5 days. I'd like to use the computer it's running on for other memory-intensive work, so I'm torn about whether ...
0
votes
1answer
263 views

MySql - is possible that performance issues are caused by dynamic SQL?

We have this MySQL SP, which uses dynamic SQL. It seems it does NOT perform well under load. It is possible that this SP becomes slow under load because it uses dynamic SQL? Can dynamic SQL cause ...
4
votes
0answers
59 views

Which to trust?

We are troubleshooting a long-running issue with a vendor. Their software has a tendency to freeze up and stop working once or twice a week causing major disruptions to our operation. They have been ...
1
vote
2answers
2k views

Improve MySQL Query Performance - Too many records

I am using MySQL RDMS for a contact management system. Now a days my database grew in size and contains more than 1 million records. Checking duplicate phone numbers became a big issue during ...
2
votes
1answer
246 views

How to speed up looped INSERT INTO statements?

I currently use the following statement, for 10,000 rows it takes about 150 seconds. I tried removing the index on the target table, but this didn't help. Running the loop without the INSERT INTO ...
0
votes
1answer
21 views

Best approach to compare specific columns of 2 tables in different databases?

I'm running an application who does have a shorten version of a table in the backend database. Both application- and backend-tables are having the same primary keys and some specific key columns. ...
0
votes
1answer
132 views

Select Query takes more than a minute to retrieve data

I have a table that has 99 columns, all of them are not needed but they were there when we started. There is a Primary Key (Objectuid) which is a GUI and has the Clustered Index on the PK. The Table ...
0
votes
2answers
59 views

How can i update my database from another database using temporary tables?

I want to update tables of my database using another big database every day with using temporary tables and without returning result. How can i update it? This my temporary table : use data_pro; ...
3
votes
1answer
200 views

Handling a chat room in a database

I have been searching all day to find a better answer to my question but those I found was useful but do not critically analyse my question. I am building a chat room using php, mysql, jquery and ...
0
votes
2answers
205 views

What's faster: two UPDATEs with WHERE (in / not in) or one UPDATE with CASE?

What's best performance wise, two separate UPDATEs: UPDATE table1 SET enabled = 0 WHERE code NOT IN ( SELECT id FROM table2 ); UPDATE table1 SET enabled = 1 WHERE ...
1
vote
1answer
17 views

MySQL Read/Write Benchmark

I'm trying to benchmark Read/Write speed in MySQL 5.5. Currently I have a stored procedure that insert rows with random numbers to a table and I'm measuring time of execution before and after ...
2
votes
1answer
312 views

Database design for a table with both bulk insert and single row insert

I have to design a table where records will be inserted in two ways. Bulk insert from a batch process from a delimited text file between 2 - 3 million rows in a short burst. Later the same records ...
4
votes
0answers
68 views

Why is my Azure SQL Server so slow?

We currently have a VM that is very underpowered and are proposing to move to an Azure VM with better specs. The problem is, the Azure VM is much slower than the original VM even though it is of a ...
3
votes
0answers
69 views

Why the stored procedure is much slower than a temporary table?

I want to do the updating of my database every day and I will like to use stored procedures but the time of execution of the temporary table is faster than the stored procedure. How can I optimize my ...
11
votes
1answer
254 views

Why does referencing a variable in a join predicate force nested loops?

I came across this issue recently and couldn't find any discussion of it online. The query below DECLARE @S VARCHAR(1) = ''; WITH T AS (SELECT name + @S AS name2, * ...
4
votes
0answers
83 views

Why is query thousands of times slower with DESC?

I have a PostgreSQL database (AWS RDS) and ran the following queries in psql: livenet=> EXPLAIN ANALYZE SELECT * FROM outputs ORDER BY height LIMIT 10; Limit (cost=0.57..36.82 rows=10 ...
1
vote
5answers
67 views

TSQL insert table using view — performance issue

I have a big view joining multiple tables that in a regular basis materialists itself into a table (this step occurs for viz's tool read a table instead of a view during data source refresh): select ...
1
vote
1answer
124 views

Why is my stored procedure very much slower than the same MYSQL query?

My stored procedure is very slow compared to a normal query or a temporary table. How can I optimize my stored procedure? CREATE DEFINER=`datasll`@`...` PROCEDURE `product`() BEGIN EXPLAIN ...
1
vote
1answer
38 views

Intervals query of huge data

My question is more or less theoretical - what is the best approch to get query data by intervals. The situation I have a system that manage counters (thousands of counters - counts consumption of ...
2
votes
1answer
970 views

How to configure pgpool for reasonable speed

I have a problem with pgpool II configured in master-slave mode with replication on slony. I have configured postgres databases on each server to run as fast as they can and this was verified by me ...
2
votes
2answers
123 views

Slow Performance caused by Correlated Sub-queries & Clustered Index Seek

I'm running a query in which one of the tables (FIELDDATA) has nearly 400,000 records which is taking more than 2 minutes to execute. I ran the execution plan, and noticed that the clustered seek ...
0
votes
1answer
47 views

Divide a PostgreSQL database into schemas

My Postgres database will be focused on multidisciplinary organizations. The project axis is: a person could belongs to diverses disciplines (ex: arts, sports) for the same organization, and this ...
1
vote
1answer
131 views

MongoDB Insert Performance

I have some data which are aggregated in chunks and later pushed into another collection. The problem is that aggregated data pushing to another collection is very slow and takes from few hours and i ...
1
vote
0answers
557 views

Postgres database zero down time production deployment

I need some idea about how I can deploy a financial application in production environment using PostgreSQL DB with zero down time. I have two servers in Master-Slave design. Currently I am giving ...
2
votes
1answer
143 views

What are possible causes for consistently volatile INSERT performance in MySQL tables?

I have a Java program running on a VM that is sequentially feeding a queue of single row INSERTs through a single connection to a MySQL server on the same VM. The queue execution is not artificially ...
3
votes
3answers
11k views

MySQL using too much CPU

I'm studying to be a DBA right now because I have a massive live database that is very sensitive that I manage. Here's the current system stats of my dedicated database server: CentOS 5.9 24gb Ram 8 ...
1
vote
2answers
372 views

Mysql improve Self join performance large table?

I have a task to help identify conflicting IP ranges , I want to highlight when one companies IP range falls within another's ... below is the sample table, I have converted the IP ranges from .dot ...
3
votes
2answers
436 views

Using Central Management Server to provide convincing performance statistics

Central Management Server The company I work offers dedicated VMware hosted servers to its Windows clients. Among those Windows clients, there are essentially 60 single instance SQL Servers ranging ...
8
votes
3answers
784 views

Worse performance on a new server

We've been on a dedicated server (single quad-core, 6 GB RAM) and are moving to a new dedicated server (2x hex-core, 32 GB RAM). Both are Windows Server 2008, SQL Server 2008. The performance on the ...
1
vote
1answer
348 views

SQL Server performance is slow when migrated from SQL Server 2012 to SQL Server 2014

We are trying to migrate from SQL Server 2012 to SQL Server 2014 on Windows 2012 R2 OS. After the upgrade, we are doing performance testing and observed huge difference in running a simple query from ...
7
votes
3answers
720 views

More Databases Per Sql Server 2005 Instance

Our company currently hosts about 400 databases per SQL Server 2005 instance. 500-600 databases and we see performance start to deteriorate. Database size ranges from 50mb to 40-60gb in the extreme, ...
6
votes
4answers
40k views

High CPU usage on SQL server - Slow queries [closed]

Our MS SQL Server is using about 95% of the CPU-power. After a server (hardware) restart, or a SQL-Service restart, the usage is 0% and slowly increases over the course of 1-3 days. Depending on how ...
0
votes
1answer
62 views

SQL Server : low disk space impacts CPU?

Is there any relation between disk space and CPU utilization? We experienced the issue with very high CPU utilization on SQL Server 2008. At the same time, we were in lack of free space on the ...
2
votes
3answers
33k views

SQL Server 2008 R2 High memory usage

I have SQL Server 2008 R2 that runs multiple jobs over night, the problem is SQL Server will eat up all RAM and CPU, then it will not release the RAM resources after the job finishes, as a workaround ...
2
votes
2answers
67 views

2 databases in sql server 2005 “Production Server”

Can 2 databases decrease the performance in a SQL Server 2005 production server? Server specs: Dell Power edge 2950, 2 Quad core Xeon, 16 GB of RAM, 3x73 GB SATA hard drive hot plug, Windows Server ...
0
votes
0answers
77 views

Linked server performace issue?

I have created a linked server in SQL Server 2008 R2 Enterprise Edition for MySQL i.e. MySQL database is accessible under SQL Server environment. I have a created a trigger in SQL Server such that ...
0
votes
1answer
38 views

Get all possible parent ids only if has parent bigger than 0

Right now If I call get_parent_id(4) I will get all id parents. This means 3,2,1. Is not hard to guess that 1 has parent 0. This is my problem. I want to output all ids unless the parent is 0. To do ...
0
votes
0answers
21 views

Working with online users based on their IP address address - mysql database [migrated]

Right now I have a box (in footer) where I'm showing online users based on three types of url location, the user type and his Ip address. I'm using individual querys to delete, insert and show online ...
0
votes
1answer
33 views

RDS Postgres Peformance

I have recently set up a new RDS instance to test out working with a AWS postgres instance vs a heroku postgres instance. What I've found is that when I load an instance of 1000 entries in RDS its ...
0
votes
1answer
53 views

Using TEXT or even MEDIUMTEXT for all text columns in a MySQL table?

I'm using a PHP script to insert millions of rows into a MySQL. Each of the rows contain a diversity of columns that are very different across the rows. Basically I'm using MySQL as a key-value pair ...
12
votes
3answers
3k views

How is LIKE implemented?

Can anyone explain how the LIKE operator is implemented in current database systems (e.g. MySQL or Postgres)? or point me to some references that explain it? The naive approach would be to inspect ...
2
votes
1answer
116 views

MS SQL high tempdb disk I/O during merge replication of BLOBs

Having a merge publication for replicating BLOBs (sql type - image), got very high tempdb disk I/O for my size of data. Publication is download-only and has no filters. High disk I/O is caused by ...
1
vote
3answers
699 views

Changing compatibility level of database causes performance improvement of stored procedure

We have a Web Application in a Windows Server 2012 Datacenter (IIS 8), running under .NET Framework 4.0, which connects to another Windows Server 2012 Datacenter with SQL Server 2012. My Database has ...
0
votes
1answer
160 views

MYSQL: How to improve performance of inserting over 1M rows to a table with over 100M indexed rows

I have this mysql table: CREATE TABLE `codes` ( `code` bigint(11) unsigned NOT NULL, `allocation` int(11) NOT NULL DEFAULT '0', `used` tinyint(1) NOT NULL DEFAULT '0', PRIMARY KEY (`code`), ...
2
votes
1answer
430 views

Best design of mongo replica set for DB read/write speed

I'm building a Node app that uses MongoDB. Whilst it would probably be fine to have node and mongo sitting on the same VPS, I want to ensure that the MongoDB is backed up and maintain high ...
1
vote
2answers
258 views

Oracle Compatible Parameter to set

Is there any difference in setting the Compatible Parameter to 11.2.0.0 vs 11.2.0.4 ? Are there any advantages / dis-advantages ?
1
vote
1answer
476 views

Internal query on CDEF$ and CON$ very CPU bound

I am checking an application (Infor ERP LN) that loads a lot of data into an oracle 10.2 database. While checking one of the user sessions with SQL_TRACE and its output with tkprof, I found that the ...