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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865 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 ...
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1answer
254 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 ...
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1answer
29 views

mysql Quiz leaderboard filter by points, time taken

I have a quiz report table which shows a report for every quiz a user takes. I need to create a leaderboard from this, which shows the top users best score, filtering by points and then time taken. ...
2
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1answer
142 views

PostgreSQL performance worse when adding CPUs

I ran into a strange behaviour when benchmarking PostgreSQL. The setup is like this: Virtual box VM, with 3 GB of RAM. The host has 16GB of RAM and 4 CPUs. Ubuntu 14.04, standard PostgreSQL 9.3 ...
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1answer
86 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 ...
2
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1answer
294 views

Is this amount of disk IO expected with MySQL?

I am running MySQL 5.5.34 on an Amazon EC2 micro instance with EBS (elastic block storage). The instance has been running for around 10 days and according to Amazon I've accumulated around 8.5 ...
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2answers
180 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 ...
2
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1answer
284 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 ...
2
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1answer
181 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 ...
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1answer
62 views

Slow “CREATE TABLE” and “TRUNCATE” on MySQL / MariaDB

I am fighting with performance issues on a local MariaDB instance. Fun thing: I previously had problems with all my INSERT and UPDATE and DELETE queries. This got signigicantly faster (~40ms -> less ...
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0answers
206 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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2answers
1k 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
11k views

What is the fastest way to insert large numbers of rows?

I have a database where I load files into a staging table, from this staging table i have 1-2 joins to resolve some foreign keys and then insert this rows into the final table (which has one partition ...
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0answers
17 views

Using Database Replay between AIX/Power7 and Linux/Intel - Potential Issues? [closed]

I'm planning to do a DB migration from AIX+P7 to Linux+Intel. We want to do a performance analysis between the platforms. However the database is massive, and before we commit to procuring the ...
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1answer
27 views

MongoLab: Does hardware effect performance of a find() query [closed]

I asked a pervious question on StackOverflow about if document size affected the performance of fetching that document (the document is 3MB in size) ...
5
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1answer
140 views

Sudden poor SELECT performance on a large table with existing indexes

My company uses a software suite in which the only thing I can truly modify is the database. We've always had performance issues (mostly hardware problems that we hope to resolve soon), but lately ...
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1answer
35 views

Migration from SQL Server 2012 Ent to SQL Server 2014 STD

We recently migrated from a traditional hosting environment with a back end of SQL Server 2012 ENT to an Azure VM running SQL Server 2014 STD. We did all the cool stuff with BPEs on SSD, etc. The ...
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0answers
33 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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1answer
124 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 ...
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2answers
40 views

How to calculate mysql server reads per second,writes per second?

Can anyone let me know how to calculate mysql server writes,reads,deletes,updates per second.
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2answers
354 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 ...
0
votes
1answer
24 views

Load & traffic balance best practices

I am about to design an enterprise solution for a large scale application in which a windows service, MVC, and many other projects will use a database, so I am thinking about load balancing and best ...
2
votes
1answer
138 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 ...
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1answer
217 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 --- ...
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2answers
270 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. ...
1
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1answer
111 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 ...
2
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3answers
49 views

Is database performance optimization independent of the size of a database or a table?

If by rewriting an operation or a piece of code the performance has increased by 30% in a program reading and writing to a table with 100,000 records, does that optimization remains same if the table ...
3
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1answer
5k views

Very slow DELETE in PostgreSQL, workaround?

I have a database on PostgreSQL 9.2 that has a main schema with around 70 tables and a variable number of identically structured per-client schemas of 30 tables each. The client schemas have foreign ...
6
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1answer
64 views

Capture and Replay workload

We have a new server which we are migrating too and want to see the potential benefits of the hardware. So the idea is that we capture a workload and replay this against our new box. My question is ...
0
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1answer
38 views

Optimizing key lookup in subquery with UNION ALL

I am trying to optimize following query (little bit more complex actually, but this is important part): SELECT Id, StatusDate, [...Lot Of Columns...] FROM ( ( SELECT Id, StatusDate, [...Lot ...
5
votes
0answers
170 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 ...
3
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0answers
37 views

SQL Server Disk IO Performace appears different between otherwise identical servers [on hold]

I have two identical servers each running Microsoft SQL Server and performing a batch processing job. Server #2 keeps timing out while processing while server #1 appears to be running smoothly. I ...
2
votes
1answer
149 views

How can I compare the server impact of transaction replication

We are developing a system that must extract data from an existing SQL Server 2008 R2 cluster. One of our design goals is to limit the performance impact on that cluster as much as is practical. ...
3
votes
1answer
103 views

How to monitor load on database server

Could anybody please suggest me a way to monitor the load on my database server? What perfmon counters should I monitor on daily basis and confirm that load on the server is increasing day by day [or] ...
2
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2answers
106 views

Seeking help to test a use case on sql server memory

This is a question which came out of curiosity to know of how SQL Server handles memory. Assume I set a very low value for max server memory and I increase my workload like running dbcc checkdb, ...
3
votes
2answers
304 views

SQL Server Baseline and Performance Optimization

I've been struggling a little bit around Performance Troubleshooting including baseline and troubleshooting of SQL Performance. Could anyone help with this or point me to where I can possibly get a ...
0
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1answer
37 views

SQL Server data, logs, backups files in mounted foldersin C:\

I know that is a good practice to have data, logs and backups files of SQL Server in diferent disk, for example D:\ for Data files, E:\ for Logs files, F:\ for backup files. But if I want to use this ...
0
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3answers
70 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 ...
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0answers
43 views

Oracle: delete/insert vs. insert/exception/update

In general is there a performance advantage for of these "upsert" methods? Or is either method preferrable for other reasons? delete then insert delete from t where pk = ...; insert into t(pk, ...
2
votes
1answer
45 views

Postgresql performance issues when issuing many small inserts and updates one at a time

I have a production web server with postgresql database. My server gets data from another server every hour on the hour. The other server wakes up and sends many requests to my server, each result in ...
1
vote
1answer
386 views

Calculating a running balance to store with transactions

I need to put a read-only copy of balance and transaction data from a legacy system, which will only be used to view/print statements. Balance | id | member_id | product_id | balance | | 1 | ...
3
votes
1answer
41 views

Pagination performance, with subquery, inner join and where

I am trying to optimize following query (this is most simplified version I could came up with): SELECT tr.Id, StatusDate FROM ( SELECT tr.Id, tr.StatusDate FROM mon.ArchivedTaskResults_201504 ...
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2answers
228 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 ?
3
votes
2answers
511 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
146 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`), ...
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1answer
38 views

how big of a role does hardware play? [closed]

I'm the developer, not the DBA. I don't know much about setting up databases but i'm concern of the setup at my current work. The server is installed on desktop PC hardware(i7, 16GB RAM, 1 TB SATA ...
1
vote
1answer
457 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 ...
1
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1answer
39 views

Is there something I can do to make this UPDATE run faster?

I have a relation EnumeratedSensorReading that includes a siteid and a quantityid column. I want to replace these two columns with a single sensorid column. I have added this column, and it is ...
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2answers
74 views

Merge faster than Insert

Are there any advantages/disadvantages of making use of a merge over a insert function? Can an insert statement make use of the `OUTPUT' Note: the ON clause for the merge is set to 1=0 (always ...
39
votes
4answers
64k views

Possible to make MySQL use more than one core?

I've been presented with some dedicated MySQL servers that never use more than a single core. I'm more developer then DBA for MySQL so need some help Setup The servers are quite hefty with an ...