Questions tagged [database-performance]
The database-performance tag has no usage guidance.
187
questions
39
votes
18
answers
940
views
Poor internal database - replace it or chuck hardware at it?
So - we have an internal company database, the usual kind of stuff: manages clients, phone calls, sales deals and client agreements/schemes.
It's an Access 2000 front-end, and an SQL Server 2000 ...
- 3,378
16
votes
2
answers
30k
views
How to calculate max_connections for PostgreSQL and default_pool_size for pgbouncer?
Is there a rule or something I can use to calculate a good number for max_connections, default_pool_size and max_client_conn?
The defaults are odd. PostgreSQL defaults to max_connections=100 while ...
- 422
14
votes
6
answers
9k
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SQL Server Express for Production Databases?
We are about to roll out a dual web/internal transactional application where each client has their own database. Each database is very small - under 50MB each, so we were wondering if it would make ...
- 1,833
14
votes
1
answer
18k
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Do I need to REINDEX and VACUUM a table after deleting lots of rows?
I am running a PostgreSQL database that has several tables which store logging information. This information is for reporting purposes only and gets dumped to a file and deleted from the database if ...
- 3,520
13
votes
2
answers
2k
views
Is there a MySQL performance benchmark to measure the impact of utf8_unicode_ci versus utf8_general_ci?
I read here and there that using the utf8_unicode_ci collation ensures a better treatment of unicode text (for example, it knowns how to expand characters such as 'œ' into 'oe' for searching and ...
- 3,935
11
votes
3
answers
7k
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Too much I/O generated by postgres stats collector process
I am using XenServer with several virtual machines having local postgres databases. Even when all applications are unused and the databases are idle, each vm causes constant storage network traffic ...
- 1,336
10
votes
3
answers
1k
views
Importance of location of installation of Microsoft SQL Server
I have a server with cheap slow disk and an expensive fast disk.
I want to use the expensive disk for all the things where it's important that it's fast, such as my databases.
To save money, I want ...
- 413
10
votes
1
answer
123k
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Mysql showing 100% CPU usage [closed]
I'm experiencing some problems with my MYSQL server installed with Cpanel.
My server is showing 100% usage of mysql even if I don't have too much traffic on web.
I am running CentOS 6.5x64 with 80GB ...
- 139
9
votes
2
answers
13k
views
How well does PostgreSQL perform with a large number of databases?
We have an web application whose architecture requires that any registered user (a company, actually) should be isolated from the other, i.e., I'll run the same webapp with the same data models, but ...
- 230
9
votes
1
answer
23k
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Maintenance of tables: do I need to REINDEX a table after truncating and repopulating?
I have a table with about 2 million rows in it of transactional data that we use for analytics. Every week we reload this with new data, so we've been using TRUNCATE to clear it out and then inserting ...
- 205
7
votes
4
answers
10k
views
postgreSQL vs Cassandra vs MongoDB vs Voldemort?
Which database to decide upon? Any comparisions?
Existing: postgresql
Issues
Not easily scalable horizontal. Needs sharding etc
Clustering does not solve the data growth problem
...
- 209
7
votes
3
answers
22k
views
How to improve AWS RDS Performance - Heavy read write updates
After searching and reading as many posts, comments and discussions I could find I did not find one specific to my issue.
I have multiple AWS EC2 deployments with a single RDS all in the same ...
- 277
7
votes
1
answer
10k
views
Understanding IXSCAN and COLLSCAN in MongoDB logs
I'm attempting to grep through some Mongo logs in an attempt to find slow operations that I need to optimize. Slow query logging is at the default and is logging operations over 100ms.
I think ...
- 4,740
6
votes
1
answer
4k
views
Bad performance for a large join query in PostgreSQL 8.4.4, despite enough memory to cache entirely
Question
How can I make the query described in this post faster, in particular by making PostgreSQL using the available RAM? - Note that I have tried to configure effective_cache_size and ...
- 427
5
votes
5
answers
5k
views
PostgreSQL High Performance Setup
I am setting up a server with the following specs:
* Qty 4 Processors (AMD Opterons with 12 cores each)
* 32 GB Memory
* Qty 8 HDD (15K SAS Dual Port)
* CentOS 5.5
* JBoss
* PostgreSQL
It is likely ...
- 111
5
votes
7
answers
2k
views
Optimizing performance across thousands of SQL Server databases
We are building an application where each client will have their own database. None of the databases are particularly large (20MB to 400MB each), but there will be ~5,000 to start and at any one time ...
- 1,833
5
votes
1
answer
27k
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What does "GC (Allocation Failure)" mean in my ElasticSearch 5.6 logs?
I see these constantly in my Elasticsearch 5.6.3 logs. Is this a signal that I should scale up and add more RAM? Or is this just normal operations for ElasticSearch?
[GC (Allocation Failure) [...
- 4,740
5
votes
1
answer
5k
views
PostgreSQL - count() performance and how to tweak it?
I've done some reading in google and the only thing I did was get myself confused.
Some of the people say that count() is slower with many records, others say you can cache the number or even use ...
- 1,508
5
votes
1
answer
5k
views
Loading large CSV into Postgres
I'm trying to load a CSV of about 100M records (around 8GB on disk) into Postgres via the copy command: copy mytable from 'path/to/myfile.csv' with CSV; I have been monitoring the progress by checking ...
- 314
5
votes
4
answers
6k
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Speeding up SQL Server temp table processing with a RAM Disk
A system we are developing consists of a Web app frontend, and a backend that does a lot of data processing using stored procedures in SQL Server 2008 R2 (please, don't ask why...). These stored ...
- 51
4
votes
4
answers
6k
views
MySQL, disk I/O and SSD drives
We have a LAMP box with 2x mirrored 1 TB WD Black Caviar disks running the whole OS and MySQL. 8 GB / RAM, 2x quad core CPUs.
We're really taxed on disk I/O, and I've been thinking of ...
- 154
4
votes
3
answers
18k
views
MySQL maintenance - how to clear the buffer?
We have a server running our PHP/MySQL-based web application which is SLOW.
My predecessor says:
We used to do database maintenance, which used to clear the buffer, cached and unwanted variables.
...
- 43
4
votes
2
answers
2k
views
extreme slowness with a remote database in Drupal
We're attempting to scale our Drupal installations up and have decided on some dedicated MySQL boxes. Unfortunately, we're running into extreme slowness when we attempt to use the remote DB - page ...
- 33.1k
4
votes
3
answers
4k
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mysql performance tuning, write, get db into ram
I am trying to improve the performance of a website by optimizing the Mysql server. In addition to general optimization I have a feeling that some write operations take an unacceptably long time.
The ...
- 283
4
votes
1
answer
1k
views
Are there any performance differences between Oracle Entreprise and Oracle Standard editions?
Someone has asserted to me that the reason why one database is performing better than another (50-100%) is because one has Enterprise Edition and the other has Standard Edition.
Given the same ...
- 1,866
4
votes
1
answer
633
views
Mysql InnoDB table size performance
I have a table that is closely approaching 2 million records. This table stores a history of transactions. This is on a high traffic website but also the table is not accessed regularly. We ...
- 3,040
4
votes
1
answer
846
views
Option shared_buffers in PostgreSQL
I have a server with 4GB of RAM and PostgreSQL 9.0.3 on Centos 5. I'm using pgbench and pgbench-tools to measure performance using two pgbench-tools queries: select and tpc-b.
With default settings ...
- 143
3
votes
3
answers
7k
views
Which is faster? 4x10k SAS Drives in RAID 10 or 3x15k SAS Drives in RAID 5?
I am reviewing quote for a server upgrade. (RHEL).
The server will have both Apache and MySQL on it, but the reason for upgrade is to increase DB performance. CPU has been upgraded massively, but I ...
- 467
3
votes
2
answers
8k
views
Store TIME in SQL
What is the correct way to store the TIME of day in SQL?
Have a field that cares only when an action took place. Example values will be 2:30 PM or 14:30, it doesn't matter to me which. This ...
- 1,565
3
votes
9
answers
789
views
Can you break down relative MySQL load by "source" of query?
I am trying to improve server performance, and it is clear that MySQL is a major contributor to the problem. Troubleshooting it, however, is very hard. I am using the slow query log to target ...
- 371
3
votes
1
answer
10k
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How can I tell if NUMA is enabled on a MongoDB server?
Our mongodb process is consistently using >100% of our CPU (this is on an Ubuntu 64-bit server on Linode) and we're casting about for performance improvements.
One suggestion we found was that ...
- 238
3
votes
3
answers
4k
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PostgreSQL 9.0.X or 8.4.X - performance, replication, stability
I've been developing an app w/ server infrastructure for a while now, and I'm getting ready to release soon(ish).
So far the server backend has been running on PostgreSQL 8.4.7, and it's working as ...
- 284
3
votes
2
answers
751
views
MySQL LOAD DATA INFILE: Better Server, Worse Performance
I am testing out Microsoft Azure Database for MySQL and have run into a performance issue that I do not understand.
I launched a "Basic" server with 1 vCore (2 GB RAM, "Standard Storage"), which is ...
- 71
3
votes
2
answers
5k
views
Maximum number of database inserts per second
I am looking at designing a system that will be recieving very many records.
Is there any fixed limit on how many inserts you can do in a database per second?
We normally use MS SQL server, is ...
- 2,229
3
votes
2
answers
9k
views
Multiple columns in a single index versus multiple indexes
The short version of my question is what's the difference between three indexes each indexing a single column and one index indexing three columns. Background follows.
I'm primarily a programmer but ...
- 298
3
votes
1
answer
359
views
Finding SQL Server Bottleneck - not CPU, IO, available memory
I'm trying to identify the bottleneck on a new SQL Server implementation (2012 Enterprise). I've been running some meaty queries/ETL jobs which are taking a considerable time - but I'm having ...
- 31
3
votes
1
answer
6k
views
Slow connection to Azure Sql Server
I'm moving from a Rackspace Cloud platform to Azure but I'm having some real performance issues. It seems like everything is a little but slower but especially database interaction.
I've done some ...
- 31
3
votes
2
answers
370
views
Very large database, very small portion most being retrieved in real time
I have an interesting database problem. I have a DB that is 150GB in size. My memory buffer is 8GB.
Most of my data is rarely being retrieved, or mainly being retrieved by backend processes. I would ...
mingyeow
3
votes
1
answer
581
views
Most efficient/quick SQL database update/restore method
I'm working on a very large database (250+ gigs) with well over 225 million records. The database is hard to work with simply from its sheer size. This database will only be used as read-only.
We're ...
- 161
3
votes
2
answers
941
views
Performance differences between EXT4 and XFS on kernel 4.15.0-76
OS: Ubuntu 18.04.4 LTS
Kernel version: 4.15.0-76-generic
Storage type: RAID10 (4 x SSD)
Question: is it a bug for this version of kernel? EXT4 run a lot slower when we perform same SQL insert test; ...
- 252
3
votes
1
answer
45
views
SQL Server 2005 global slowdown
Two days ago our production server suffered a massive slowdown where the primary symptom was that an extraordinarily high number of requests were suffering SQLTimeouts. I will quickly describe our ...
- 31
2
votes
4
answers
2k
views
master-slave-slave replication: master will become bottleneck for writes
the mysql database has arround 2TB of data.
i have a master-slave-slave replication running. the application that uses the database does read (SELECT) queries just on one of the 2 slaves and write (...
- 1,463
2
votes
3
answers
4k
views
Do InnoDB or MyISAM tables offer better insert performance in MySQL 5.1?
I need to insert rows as fast as possible into a database with freshly created tables and no indexes. I'm looking at on the order of 20M rows, which is not that much. Would InnoDB or MyISAM tables ...
- 419
2
votes
3
answers
1k
views
How do multiple servers work in terms of databases? [closed]
I don't know an awful lot about servers, but I do know that there are many ways you can improve the performance of running a web application, in terms of hardware.
For example, starting with a single ...
- 595
2
votes
3
answers
482
views
What would be better solution a single database or multiple databases, one for each customer
I building a software that is going to have a lot of users (hopefully) I will have users that dont have much records or exceed normal data and I would also have the big users which will have millions ...
user55561
2
votes
3
answers
2k
views
MySQL becomes unresponsive a few times per hour
I'm stuck trying to solve a MySQL issue. A few times an hour, for about 60s, MyuSQL becomes unresponsive, causing our site to be inaccessible during that period. I enabled the slow query log and found ...
- 293
2
votes
4
answers
6k
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Need help with Access Database with Front End and Back End really slow with more than 1 user
We have had a consultant install a database for a client that is based on Access 2007 with a front end (on each workstation) and I guess the database back end (on the file server, it is a server 2003 ...
- 1,244
2
votes
3
answers
1k
views
How can I speed up SQL Server queries on Amazon EC2?
Our SQL queries sometimes take too long. We have a Windows Server 2003/SQL Server 2005 setup. We have already created indexes everywhere that's possible. Can we get quicker disks? Any ideas from ...
- 337
2
votes
3
answers
859
views
PostgreSQL lots of writes
I am using postgreSQL for a scientific application (unsupervised clustering). The python program is multi-threaded so that each thread manages its own postmaster process (one per core). Hence, their ...
- 147
2
votes
1
answer
334
views
One user for all databases or different user for different databases?
I have multiple (Wordpress) websites that use different mysql databases. I would like to know if I should use different users for different databases, or just use one user (such as root) for all ...
- 113