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

0
votes
1answer
30 views

Application is hanging when database upgraded from SQL Server 2000 to SQL Server 2008 R2

Presently we are working with SQL Server 2000, the database is perfectly working with our software for retail sales counter application developed with VB 6.0. But after upgraded to SQL Server 2008 R2, ...
0
votes
2answers
17 views

MySQL always writes simple temporary/memory tables to disk (both tmp_table_size and max_heap_table_size are set to 8GB)

I'm struggling with this issue and just can't figure out why this is happening. CREATE TABLE sitecache._test ENGINE=MEMORY SELECT * FROM website.gallery_likes WHERE 1=0; Every time I execute this ...
1
vote
1answer
37 views

Non-sequential Primary Key performance in PostgreSQL 9.3

Due to requirement to support distributed environment, each of my clients has been assigned unique node id, it appends the node id with running number as primary key and stores at local database. E.g. ...
4
votes
0answers
55 views

Timestamp-based index

I have a big database (200GB+) that contains some log info. And I want to speed up SELECT queries and stored procedures. I have a table with a GeneratedOnUtc datetime column, and have a non-clustered ...
0
votes
0answers
15 views

redshift performance effect if use 32 character long unique string as Primary key instead of auto incremented int

In my analytics application I am creating 32 char long unique string for each hit as user_session. In current implementation, I am storing user_session in tbl_sesssion in session column and I am ...
0
votes
1answer
18 views

Can I extrapolate from the progress reporting in MyISAM ALTER?

I'm migrating a 300 million row MyISAM table to add some indexes. Just because it might be relevant, here's my ALTER statement: ALTER TABLE my_table ADD UNIQUE INDEX my_table_abcd (a, b, c, d), ...
2
votes
1answer
60 views

Oracle 11g connect overhead

Currently one of our new applications is connecting to an Oracle 11g instance over 30,000 daily (at every user request) via their application server, using the same account. (it will be significantly ...
0
votes
0answers
26 views

Multiple subqueries performance issue

I have a query that collects customer data. I select a lot of correlated data from different tables. I want to have only ONE result row for each customer. The query looks like that: SELECT c.Id ...
0
votes
1answer
22 views

Reusing covering index for fields in FROM, from another query's index

For the following query I have a covering index as so: SELECT bar_id FROM foo WHERE user_id=:user_id AND date_sent=:date_sent; ALTER TABLE foo ADD INDEX (user_id, date_sent, bar_id); Now I have ...
1
vote
1answer
66 views

Query on 250 million records

I have a table with below structure CREATE TABLE [dbo].[ColumnValues]( [Id] [int] IDENTITY(1,1) NOT NULL, [ColumnId] [int] NOT NULL, [Value] [nvarchar](max) NULL, [OutputArea] ...
0
votes
0answers
33 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 ...
0
votes
1answer
15 views

Query running slow on script and producing error 500 when run in phpmyadmin

I have a query that seems to take a good 30 seconds to execute even when the query produces no results. There are 4000 lines within the database and queries that produce all results run within ...
2
votes
1answer
36 views

io_stall question

I just installed SQL Server on new hardware and ran a test script to show io_stall information by file. Nothing else has been loaded yet, just a fresh install of SQL Server 2012. Why are the ...
0
votes
1answer
39 views

Improving lots of Left Joins ( SQL Server 2008 - procedure )

This query is running with 8 minutes to complete. I'm trying to help the programmer with this task. I've created indexes and stats, update_stats and rebuild indexes but none of this is helping us. ...
0
votes
0answers
12 views

Performance/Maintenance Implications of a Write Heavy Table In An Otherwise Normal “CRUD” Database

We have a small-ish (<100,000 rows) MySQL database (on Amazon RDS). Its supporting a fairly simple read heavy CRUD web application. Currently we're building out a web analytics system. It will ...
1
vote
1answer
186 views

Designing a High Score/Leaderboard table

I'm looking for input on how to design a highscore table for a game I'm creating. The database I'm using is postgres. That's not really something I can or want to change (unless there's very good ...
1
vote
2answers
114 views

OLAP or OLATP - How to determine

I have SQL express server with database that is used by one application. I am trying to optimize the DB but am not sure if the DB is OLTP or OLAP. There is no analysis server installed, the DB is ...
0
votes
0answers
41 views

SELECT query on mySQL taking 20 seconds to execute

Many points to note: This SELECT statement is happening both on my site, terminal, and on phpmyadmin, so the problem isn't a coding problem. If you delete the 11,000,000 rows and keep 20,000 rows ...
6
votes
1answer
462 views

Would index lookup be noticeably faster with char vs varchar when all values are 36 chars

I have a legacy schema (disclaimer!) that uses a hash-based generated id for the primary key for all tables (there are many). An example of such an id is: 922475bb-ad93-43ee-9487-d2671b886479 There ...
0
votes
1answer
28 views

MySQL performance of applying unique constraint single column vs combination column

I have a large MySQL InnoDB table containing around 137 million rows. I need to add a unique constraint to the table. We have two options: 1) A combination index on three columns, one of which will ...
5
votes
2answers
154 views

Feasible to have thousands of users in Postgres?

We are creating SAAS where we will at most have 50.000 customers. We are considering creating a user in the Postgres database for each customer. We will map each user that logs into our service to a ...
0
votes
1answer
59 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`), ...
3
votes
2answers
83 views

When does SQL Server determine to use a new index?

I have been performing some maintenance on a server that runs some software the company bought, so I can't really change how the queries have been written. I have used some tools to determine some of ...
3
votes
3answers
114 views
+50

Clustered index performance consideration in MySQL & PostgreSQL

In MySQL/InnoDB, the clustered index is synonymous with the primary key, so picking up a poor primary key affect your db performance, i.e. use of UUID as PK is a performance killer for database write. ...
2
votes
1answer
66 views

Optimise huge Postgres table for fast read

I'm about to create a Postgres table with 1.5 billion rows. The table will just have a single TEXT column. The table is effectively a blacklist. When a user of my software saves certain data, this ...
1
vote
0answers
58 views

Excessive CPU Usage caused by long running query?

We have been getting intermittent excess CPU usage at 100%. There is not a whole amount running on the system. We also get warning of Batch Requests/sec above threshold.: 1030, which would seem to ...
1
vote
1answer
64 views

What does a “Buffer cache hit ratio” of 9990 mean?

I got this query from a blog post: SELECT object_name, counter_name, cntr_value FROM sys.dm_os_performance_counters WHERE [object_name] LIKE '%Buffer Manager%' AND [counter_name] = 'Buffer cache hit ...
0
votes
1answer
51 views

Scaling PostgreSQL TRIGGER(s)

How Postgres triggers mechanism scales ? We have a large PostgreSQL installation and we are trying to implement an event based system using log tables and TRIGGER(s). Basically we would like to ...
1
vote
0answers
28 views

Replication / Bulk Update between Servers

I'm looking to update several tables between two servers daily to have a replica of the data available. My question is, what is the least resource heavy and most effective method to implement this? ...
-1
votes
0answers
22 views

Need urgent help for DataBase design decision [duplicate]

I am designing database for B2b market. Catalog: is Colletion of Product,size,prices,delivery date and other data. I need to design catalog on basis of three datasourceType .On The basis of ...
1
vote
2answers
80 views

Oracle nologging impact for REDO Generation

Oracle database is on noarchivelog mode and tablespace is configured with nologging option keeping there will not be a situation to recover any data in mind. Following scenario was occured during ETL ...
0
votes
1answer
76 views

Compare two big tables in PL/SQL

I need to implement comparing 2 tables by set of keys (columns of compared tables). By this comparing i should check equal records (equal = equal by set of defined keys (columns in these input ...
0
votes
1answer
69 views

Identity/Primary Key columns pattern for performance in SQL?

I was discussing about database layout/design with a friend and I got some questions about performance and best practices. I'm mainly a software programmer, so I may lack "common sense" regarding ...
7
votes
4answers
584 views

At What Point Should I Split or Partition a Very Large but Simple Table

Our site has some large but simple (INT, INT, DATE) tables for stats. Each table has up to 300,000,000 rows, and gets bigger every day. The hosting provider has suggested that we split or partition ...
2
votes
1answer
47 views

Resource cost of a blocked query

I'm currently reviewing a case where an SSRS server is experiencing frequent blocking and deadlocking. The reports are not business-critical, and they are frequently killed to alleviate the blocking. ...
4
votes
2answers
1k views

Join on dm_db_index_physical_stats very slow

I'm running a small query below in a MS Dynamics AX 2012 database and it runs more than 5 minutes which I had to cancel and it is showing PAGEIOLATCH_SH wait type. The database data file is 560GB and ...
2
votes
0answers
29 views

Can CTE sub-statements be prevented from executing at all?

Through this strategy, time consumed by queries for my application have dropped to extreme lows; however, some queries consume more milliseconds than necessary. The reason why is that upon ...
3
votes
1answer
45 views

Best Design for this “Sweepstakes” Project?

Hello there fellow developers, Merry Christmas first aff all, and i hope you will have a happy new year soon. :) I was having more or less a problem with an idea that came to my mind. I am currently ...
1
vote
2answers
93 views

How to tune the below query

I am currently working on below table structure to pull the data/ generate any one time report. Let us consider the table name to be ABC. ID Field Value 1 Name Nagarjuna 1 Gender Male 1 ...
1
vote
2answers
95 views

Unexpectively slow data loading into Oracle

Big amount (4.000.000+) of files (1-4Mb each) are loading into Oracle 10g for about several days. Table is allocated in big tablespace, which was created on special volume (labeled BIG_VOL) over ...
0
votes
0answers
54 views

Data warehousing: data transfer process too slow with larger batches

I have two primary instances of SQL Server, one for OLTP and one for reporting. The data warehouse for reporting is basically a Type 2 SCD: every table has DWDateStart and DWDateEnd columns and the ...
0
votes
0answers
38 views

What minimum RAM should the server have for a Django application with Postgresql server?

I have a Django application. The database is Postgresql with 8GB size. We are also using Nginx with gunicorn. Will a 4GB server be enough for good performance ( like on Digital Ocean) ? I was under ...
0
votes
0answers
20 views

JDBC4/SQL or Hibernate/ORM?

I have an upcoming thesis project that may be used by the school itself if the system proves to be good. It is a web application (Struts2) for an Online Teacher's Performance Evaluation System. The ...
0
votes
0answers
96 views

Oracle - Slow queries without prepending schema name or providing hint

I am logged in as the schema owner in Oracle 11gR2 on Linux. I have 55 million rows in table. select max(col) from table; - takes 300 seconds (index full scan) select max(col) from schema.table; - ...
1
vote
1answer
103 views

optimize design for a table with 50 columns [closed]

I have a table with 50 column and one of my friend has told me to split the table in 4 different table to save 12 column in each table. He proposed a design to have Master table and refer the PK of ...
0
votes
0answers
8 views

Can MySQL Index Merge an Composite index with a single column index?

I am tuning a query and currently have an index as following : Index 1 : (col1, col2) An example query would be : SELECT * FROM t1 WHERE col1 = '1' AND col3 = '2'; I have created an index on ...
1
vote
1answer
45 views

Best approach to get last value inserted

I have several devices that report via Edge network their position (and more data) to a UDP server which directly inserts this data in a SQL 2008 r2. I want to know which is the best approach to ...
0
votes
1answer
60 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 ...
4
votes
2answers
64 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 ...
0
votes
0answers
44 views

Physical Table being used a Temp Table in a warehosue. Any advantage?

As I stated in previous posts I've inherited a warehouse based on SQL Server framework. In my continuous review of existing components and the practices adopted by the predecessors I found something ...