Questions tagged [database-tuning]
Performance tuning done by adjusting database parameters or physical layout of the database.
19 questions
43
votes
7
answers
48k
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Is it better to store images in a BLOB or just the URL? [duplicate]
Possible Duplicate:
Files - in the database or not?
I was wondering if there's any good reason to still use blob fields in a database. A couple of years ago I worked with a DB with a bunch of ...
- 1,874
5
votes
1
answer
1k
views
Should I use a storage engine other than MyISAM to optimise these tables or should I get better disks?
There's a production database I'm working on, whose 4 largest tables contain between 4 million and 10 million rows each and about 15 fields each, with indexes on different field types (numbers, ...
- 163
2
votes
1
answer
4k
views
MySQL with high CPU and memory usage
here we have a VPS with 3.2GHz quadcore processor with 2GB of RAM and 4GB of SWAP which need to work with a high intensive legacy system (read: bad coded). The main problem is that the CPU (~80 - 100%)...
- 183
33
votes
3
answers
108k
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MySQL creates temporary tables on disk. How do I stop it?
We are running a site (Moodle) that the users currently find slow. I think I have tracked down the problem to MySQL creating temporary tables on disk. I watch the variable created_tmp_disk_tables in ...
- 463
2
votes
2
answers
1k
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Need Help maintaining multiple databases for a multi-tenant application?
i need some information about multiple databases for a multi-tenant application ?
I am working on a project in which we are maintaining separate database for every company?
The Companies Database ...
- 21
7
votes
1
answer
14k
views
How do you increase MySQL performance using current server resources?
I have a MySQL database and some of my queries became slow. Query time is not stable. Most of the queries are fast, but some of them (may be that reads and returns less data) take long time.
I know ...
- 465
4
votes
1
answer
546
views
Proper Database Partitioning
I had asked a previous question "Proper technique for storing users event data" and the correct answer in my opinion was to create a database partition. Now from what I have read on it there are ...
- 440
2
votes
2
answers
5k
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Tuning Java Pool after getting ORA-04031
I'm running Oracle 12.2.0.1 Standard edition on Windows 2012 RC2.
I'm NOT running Oracle's Automatic Memory Management.
We are seeing these in the alert log:
ORA-04031: unable to allocate 4096 ...
- 134
32
votes
2
answers
3k
views
Where can I find database tuning exercises for learning?
As a developer, often DBAs take responsibility for resolving performance issues at the database level so we don't get that much experience diagnosing, tuning, refactoring queries etc.
I'm looking ...
- 421
12
votes
3
answers
2k
views
Executing same request from C# VS SSMS give different execution time
I have a request like this one
SELECT
[EstimateId],
[CreationUserId],
[EstimateStatusValueId],
[LanguageId],
[LocationId],
[EstimatorUserId],
[FilterUnitSystemTypeId],
[EstimateNumber],
[...
- 1,062
10
votes
2
answers
25k
views
Could not continue scan with NOLOCK due to data movement
We run SQL Server 2000 and we get a few of these errors every night.
Could not continue scan with NOLOCK due to data movement
The query that throws this error is a large complex query that joins ...
- 385
5
votes
1
answer
192
views
How to tell if database tuning is fruitful (PostgreSQL)
As a DBA, I regularly observe my database, tune up some queries (either getting the programmers to re-write it or add index or update statistics if that's what is needed, etc). I also tune up the ...
- 988
3
votes
1
answer
2k
views
Reading a SQL Server Execution plan
I am very new to any type of tuning but have been learning more.. One of my specific databases one of the problems identified with slow queries are a number of Implicit conversions. It is my ...
- 447
3
votes
1
answer
1k
views
Use of integer instead of interval (of one type)
Our DB design presently has a interval column which will only be storing days (no other interval type) so it is making sense to use INT2 (smallint) instead of interval. Reference to documentation.
...
- 180
2
votes
2
answers
8k
views
Restore data from remote server using ".sql" file
I have a ".SQL" file which contains data at a remote server. I could download that file to my local machine and import data in my local DB, but because of network issues, and the size of ".sql" file (...
- 565
2
votes
2
answers
12k
views
How to optimize MySQL for large BLOB updates
I have a table that holds large BLOBs (up to 10M), and is updated frequently. The problem is that UPDATE statements can take up to 1 second to execute, and due to app design this blocks UI. I need to ...
- 131
2
votes
1
answer
256
views
Slow Query Gets Even Slower After Indexing
I have a MySQL database with just one table containing 8 million records. I need to query the table to find a single record that matches a specific number:
select * from my_table
where
(...
- 21
1
vote
2
answers
2k
views
Very high load avg for MySQL database [closed]
I have a backend server which response to my clients app, it has more than 20k~25k hit per second and this make my server load average very high, I believe that my MySQL config is not appropriate.
In ...
- 111
1
vote
2
answers
10k
views
What is the default size of text field in Postgres?
In the official documentation (http://www.postgresql.org/docs/9.1/static/datatype-character.html), it states text field is variable unlimited length.
I wonder what is the default size of this field ...
- 231