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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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 ...
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1answer
24 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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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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0answers
31 views

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

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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0answers
49 views

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

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 ...
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2answers
54 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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0answers
37 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 ...
2
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0answers
55 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 ...
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2answers
17 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 ...
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0answers
18 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 ...
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1answer
22 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
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1answer
39 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 ...
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2answers
65 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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1answer
30 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 ...
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3answers
36 views

SQL Server Compact - Will it perform well with heavier traffic sites? [closed]

I'm using Orchard CMS, and on initial setup, the default setting is to use SQL Server Compact. I'm not too knowledgeable about different database types and performance. So, will SQL Server Compact be ...
0
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0answers
31 views

MySQL: Optimize query with a range and distinct count

I have a query on a large table with millions of rows that looks like this: SELECT COUNT( DISTINCT clicks.tx_id ) AS unique_clicks_count , clicks.offer_id FROM clicks WHERE ...
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0answers
27 views

How index work in case of write operation?

We have two cases:- Insertion :- Cluster Index:-- Insertion :- we have number of user which we doing insertion new records. For .........example 27 users had inserted 27 rows in 1 ...
1
vote
1answer
37 views

Oracle performance loss from 10.1.0.2 to 10.2.0.5

I am testing an application on two database servers with the same data : 10.1.0.2 on Windows (for development) 10.2.0.5 on Solaris (for validation). We have a script which recreates a huge table ...
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1answer
22 views

Limit distinct count of group by

Suppose for simplicity that I have a table t with columns id and value. I can find the ids that have more than one distinct value using a query such as SELECT id, COUNT(DISTINCT(value)) AS count FROM ...
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0answers
28 views

Did I Properly Diagnose That It's Not A SQL Server Issue?

We have a job that populates about 450,000 rows nightly in an update/insert job via a stored proc nightly. The .Net app pulls in data from a noSQL DB via an API call then pushes it out via a stored ...
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2answers
50 views

Can an EXISTS clause be improved when the condition is checked for the same value multiple times?

Assume that I'm modelling a Blog engine. Blogs have n Posts. Each User can be granted a role on different Blogs (Admin, Approver or Editor stored as enums/ints). Each Post can have a State (Draft, ...
1
vote
1answer
27 views

How to Implement Different Object Types as Similar Tables?

I have a database I am attempting to design. I am trying to determine the best approach to declare similar, but different types of objects, each with their own sets of properties (perhaps some ...
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0answers
29 views

Horribly slow MySQL (InnoDB) updates, multiple workers

I've created a PHP daemon that reads records from a MySQL InnoDB-table, analyses it and then updates the record. This process is spread between multiple workers (and servers) using Redis. However, ...
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0answers
9 views

How to find an application for a specific system?

I have a distributed storage platform that I wanted to test. I launched a benchmark (i.e. IOzone) over it, given the following workload: I/O size = 4kB, 100% read, and 100% write, random access. ...
2
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2answers
80 views

Is it possible for increasing the SQL Server max memory limit to degrade performance?

As far as I can tell, raising the SQL Server max memory limit has no drawbacks, provided that sufficient memory is left for the OS and other applications. Assuming this is the case, can there be any ...
0
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1answer
51 views

How database buffer pool work?

For example we have 2 scenarios: Scenario 1:- We have very small buffer pool size of 100MB. My query data is 500MB. Does the system keep 500MB query data in RAM such that a new ...
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0answers
26 views

Application running slow when querying against SQL Server 2008R2

I'm having an application that is starting to run really slow when inserting and querying data from a SQL Server. The database is on a dedicated virtual box with 10 GB ram, AMD Operon 6134 processor ...
3
votes
1answer
37 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 ...
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0answers
15 views

Galera cluster consume many CPU percent and CPU high load

I have implemented a cluster include three nodes: two stored nodes and one garbd (also haproxy - load balancer). Some information about servers: SSD 480G Raid1 Memory 32G Swap 16G 2xCPU, number of ...
0
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1answer
20 views

my.ini configuration for a huge server

I have developed a web based app in PHP MySQL and Flash Builder. It was running fine until a few days ago when the client began to connect a lot of users. Then the app started to freeze and sent ...
0
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3answers
10 views

How can I speed up an sql query that round trips between two tables

These tables are not that big, but the time taken to process this query is long. What can I do with the following queries to speed up the process taken to return results? $msc=microtime(true); ...
0
votes
1answer
46 views

Columns count in SELECT query and SQL Server buffer cache

Let's assume that I have a table with 30-50 millions records. It has ~40 columns. Currently when I request data it always requests all columns because of legacy ORM that we use. I know that if we ...
3
votes
1answer
53 views

Help with indexing narrow table with many millions of rows

I have a good amount of experience with SQL Server, but not much with indexes and I fear I'm a little bit out of my depth in trying to figure out how to correctly structure a table that has 100+ ...
2
votes
1answer
80 views

Query shows SELECT 0

I'm looking through the queries being executed by a third party application. The application was flagged as being slow by some of our end-users. It seems to INSERT records into a HEAP, then DELETE ...
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0answers
24 views

Optimizing postgres row overlap constraints involving UUIDs and GIST

For various reasons all my tables have UUIDs as primary keys and I need to exclude duplicate rows where the combination of area_id, user_id, and finished_at <-> started_at window. The only way I ...
0
votes
1answer
76 views

Increase performance WITHOUT adding indexes [closed]

I'm having a rather large table (350MB, 1.3M rows) and there are dozens of queries arriving at this table every second. Most queries are super-fast thanks to indexes - but some others aren't. ...
1
vote
3answers
35 views

MySQL select with between optimization

I got issues with some geo IP query. So basically here is create code of table: CREATE TABLE `geo_ip_city` ( `id` INT(5) UNSIGNED NOT NULL AUTO_INCREMENT, `begin` BIGINT(20) NOT NULL DEFAULT ...
0
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2answers
24 views

MySQL rapid Data Replication from multiple Databases

I am a Freelance Web Developer but not a Database Administrator at all except basic Database Operations like DML etc. Today I got a client asking me to develop a Web based application but there is a ...
1
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1answer
44 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
1answer
54 views

Can I trigger events based on timestamp data or should I use polling?

I'm asking this question for SQL Server 2008+ but this could really be for any DBMS. Imagine you have scheduled data, something like: ID Data Timestamp 0 NULL 2014-11-22 1 ... ...
1
vote
1answer
38 views

postgres materialized views and indexes to improve aggregate performance

I have a large table with a number of materialized views used for pre-calculating aggregates. New data is inserted only once a day so think of this as a data warehouse type system. Obviously when I ...
1
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0answers
32 views

Allowing users access to SQLPLUS and to compile PLSQL [duplicate]

As a DBA - assuming my users are knowledgeable with PLSQL and SQL - why would I not grant my users privileges to compile and run their own PLSQL code. We have an MI database environment where the data ...
1
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0answers
40 views

SQL Server spending a lot of time creating sp_dbmmonitorupdate

I have an SQL Server 2008 R2 Standard with around 80 databases, 18 of which are a synchronous mirror primary. I'm having a lot of complaints about database speed lately, so I've started digging with ...
0
votes
1answer
15 views

MongoDB Tag-Aware Sharding Workflow

I wonder the work flow of sharding cluster in Tag-Aware Sharding. --- Sharding Status --- sharding version: { "_id" : 1, "version" : 3, "minCompatibleVersion" : 3, "currentVersion" ...
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0answers
42 views

MySQL 5.6.19a InnoDB Concurrent Insert

I've looked through most of the threads on this topic but still had question I was hoping someone would be gracious enough to help with. I am seeing low CPU usage and write latency but transaction ...
0
votes
1answer
50 views

Similar hardware, Same DBconfiguration and Database but different status variables result between Windows and Linux server

I have two database servers - one is Windows - 2008 and another is RHEL5 with similar hardware configuration. Both OS are 64 bit. MySQL 5.1.58 community edition is installed on Windows servers while ...
0
votes
1answer
35 views

Improve the insertion rate of mongo sharded cluster

I can't disable the write concern while i mongorestore with .bson file. It totally damages the insertion rate (insert/sec). This is my sharding status. mongos> sh.status() --- Sharding Status --- ...
3
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0answers
54 views

AlwaysON : Log_Send_Queue_Size is increasing but the log_send_rate keeps decreasing?

Question Why, despite the increasingly log_send_queue_size for these two databases, did the log_send_rate keep decreasing? There were no bandwidth issues on the network at this time, and no other ...
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0answers
44 views

SQL Server is very slow [closed]

In company with 30 clients(computers), after 3-4 hours working with financial software, SQL Server is very slow SQL Server can not free used memory and the query execution time is very slow but after ...
0
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0answers
36 views

PostgreSQL queries slower than before?

I am using PostgreSQL 9.3 server on my production server. Everything had been working fine for the past couple of months. But since the past week or so, PostgreSQL seems to have becomes very slow with ...