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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1answer
19 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 ...
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1answer
15 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 ...
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2answers
2k views

Oracle query is slower the second time

I have a general question about something I'm seeing in performance tuning in Oracle. I have a query that I'm testing. It's too big and complex for me to provide a simple example, sorry! (I tried ...
8
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2answers
242 views

Minimizing Indexed Reads with Complex Criteria

I'm optimizing a Firebird 2.5 database of work tickets. They're stored in a table declared as such: CREATE TABLE TICKETS ( TICKET_ID id PRIMARY KEY, JOB_ID id, ACTION_ID id, STATUS str256 ...
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0answers
59 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; - ...
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5answers
3k views

Is it advantageous to scale out using multiple SQL Server instances on the same server?

For a use-case of 9 databases spread across 3 time zones, is it advantagous to spread the databases onto multiple SQL Server instances on the same server? What will I gain and what will I lose? ...
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0answers
33 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 ...
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0answers
21 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 ...
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1answer
244 views

MySQL select by primary key against 100M of records within 30ms

I have no expirience with MySQL and database performance tuning in general. Wondering whether it is possible to perform a large number of selects against 100 millions of records by primary key within ...
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0answers
10 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 ...
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0answers
59 views

What is more important for Oracle DB performance, number of cores or memory size? [closed]

Oracle has quite drastic licencing policy based on the number of cores. Can we save by providing a server with less cores, but more memory? Or is the number of cores the most crucial factor for the ...
2
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4answers
460 views

Help understanding SQL Server 2005 execution plan

One of my stored procedure has long execution time (average around 4 to 7 minutes). Now I trying to tweak it an make it run faster. I am looking at execution plan and two things I see that using ...
7
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1answer
87 views

Is there a performance hit by breaking out tables into different schemas in SQL Server?

Is there any kind of performance hit when querying by placing tables in different schemas in SQL Server. For instance if I had 2 tables, Table1 and Table2, and put Table1 into the test schema and ...
0
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1answer
28 views

Large long-running reporting queries are causing very slow new mysql connections

Usually, mysql's connecton time is in the 0.001 second range. However, when I run a large reporting query (that spans multiple tables with aggregates), I get tons of warnings saying that new mysql ...
2
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1answer
71 views

A table with 50 columns

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 ...
2
votes
1answer
209 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 ...
3
votes
2answers
293 views

Query planner thinks doing a sequential scan on a very large table is faster than using an index?

I've got a query that selects the most favorited photo for each of the last 12 editions for a particular domain (this is just a segment of a larger query, but the problem seems to stem from here): ...
0
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1answer
525 views

How to configure my.cnf for Mysql 5.1, which is using too much CPU?

I am new Database engineer. I am having trouble in my server which is using too much CPU on database query(simple count statement). I have googled about it, so i found out it depends on system ...
0
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0answers
5 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 ...
3
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2answers
372 views

SQL server query is slow *without* including execution plan

I have just set up fresh installation of SQL Server 2012 on a new server and I'm experiencing very strange performance problems. Long story short, for some reason not including execution plan makes my ...
2
votes
1answer
87 views

SELECT query with DISTINCT on a table-structure for graphs is very slow

I have 2 tables where nodes contains about 60m rows and edges about 500m rows (both growing fast). These two tables represent a directed graph. CREATE TABLE edges ( node_from bigint NOT NULL, ...
4
votes
2answers
56 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
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1answer
195 views

DB disk space requirements comparision between MySQL versions

I have 2 labs where MySQL is installed. DataBases are created and deleted dynamically by certain internal processes. InnoDB is the Engine used. In one lab, MySQL version 5.0.77 is installed. The DB ...
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2answers
633 views

What is com_set_option?

As the title says, I'm wondering what is this command and why am I seeing a large amount of this query on my database? It's currently 13.30% of my total queries. I've tried googling this but there's ...
0
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1answer
89 views

Oracle 11g max login fail attempts workaround

My problem with database starts with situation where I cant really modify anything in database. My project specialist has limited time to help me. Here is the thing: My user in Oracle database has ...
0
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1answer
48 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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1answer
30 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 ...
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2answers
175 views

Improving a search query [closed]

I have a query for search function. Basically search function allowed user to define what they "have" and "want". Then this query will filter out all the possible result which created by other user. ...
3
votes
1answer
52 views

PostgreSQL 9.4 analysis, performance of normal column, indexed column and jsonb key

If I have a table containing: CREATE TABLE test( id SERIAL PRIMARY KEY, name VARCHAR(200), age INT, data JSONB ); and data column populated with {"name": xxx, "age": yyy}, sometimes ...
0
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2answers
89 views

VARCHAR primary key - MySQL

Currently, I have a categories table with 2 columns - category VARCHAR(50) NOT NULL PRIMARY KEY and parent VARCHAR(50). The parent column is a foreign key (FK) to the category column. This seems like ...
2
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0answers
60 views

Prepared statement overhead

I am using libpqxx to communicate with a PostgreSQL 9.3 server. For multiple table inserts, if they are split into individual prepared statements, they cost approximately 2ms each. If they are all ...
-5
votes
0answers
32 views

How much space does database takes to store twitter data? [closed]

Context I am going to collect twitter-data(user,s followers, timestamp, content, url and Hashtags) weekly and it continues for an year. I have a total of 160 hash-tags, and I will be creating an ...
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2answers
68 views

Security or performance risks using SQL CLR [closed]

Are there any particular security or performance risks in using the CLR in SQL Server ?
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2answers
794 views

How to fix slow LIMIT queries with big offsets without heavily rewriting them?

Imagine a very basic example of your average discussion board. For example: CREATE TABLE threads ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, title VARCHAR(100), PRIMARY KEY (id) ) CREATE ...
0
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2answers
172 views

mysql need help optimizing query

I have a table containing servers logs, and another table containing rules to match certain and drop them. The logs tables contains around 1 million rows, and there are about 20-30 rules. The ...
0
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1answer
108 views

How to track IOPS statistics?

Is there a way to access statistics about IO operations per second in DB2 9.7? I am not interested in the buffer pool hit ratio, just IOPS.
0
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0answers
38 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 ...
3
votes
2answers
274 views

Why is my CPU usage increase after setting database to read-only on SQL Server 2008 R2 [closed]

I administrate a reporting database. We run all the de-normalization process on a database DB1 daily, then we copy all the data to an another database DB2 on the same server which is queried by web ...
0
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1answer
174 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 ...
1
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1answer
125 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
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0answers
22 views

Database design for price comparison site - too complex?

I'm working on a regular price comparison site with two exceptions. I want to show price history and also allow users to subscribe to a product with a specific size and color. As a result, I've ended ...
0
votes
1answer
45 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 ...
1
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1answer
26 views

MySQL Latest Deadlock Explanation

Can someone explain this deadlock to me? It seems as if there are 2 inserts happening within milliseconds of each other with the same Primary Key. I'm not sure how this can cause a deadlock. At most a ...
0
votes
2answers
61 views

Does it make sense to order condition in where query?

We have a clustered index in table Tbl with order of A,B,C. Does it make senses to write a query to have WHERE A = @a, B = @b, C = @c or it'll be as same as WHERE C = @c, B = @b, A = @a Does the ...
0
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1answer
32 views

large SQL Performing quite slow (roughly 2 seconds for 290 rows) when having to deal with entries that can be NULL

SELECT version_stamp, pscdesc_id, psc, pscdesctext FROM pscdesc_history WHERE ( psc IN (SELECT psc FROM pso_history AS c ...
7
votes
1answer
1k views

How to determine if there are [idle connections with] uncommitted transactions in PostgreSQL?

According to a comment on this question I asked about idle connections in PostgreSQL 9.2, some uncommitted transactions (possibly related to some of those idle connections) might cause some ...
0
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1answer
325 views

Amazon RDS CPU Usage keep increasing without any long running process in Show Processlist

We are using Amazon RDS(db.m2.2xlarge), CPU usage is suddenly increasing gradually even after we reboot the DB Server. This is happening just past 2 days and we didn't give any new build recently. I ...
0
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1answer
645 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 ...
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2answers
110 views

MySQL/MariaDB Limitations

we're running MariaDB on our DB server. We have to install multiple databases on each DB instance (in fact each DB server runs multiple MariaDB instances) because each database must be separated. ...
0
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2answers
110 views

Slow INSERT/UPDATE on InnoDB

I have a problem with the performance of my MySQL server, let me explain: I instaled a MySQL server, version 5.5.20 Server version: 5.5.20-log Source distribution SELECT queries runs fast on ...