1
vote
1answer
2k 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 ...
1
vote
2answers
211 views

Low priority batch processes on live Mongo database

We want to run MapReduces on our live Mongo database, mainly so that we can extract metrics. However, we've had some bad outages caused by these MRs bogging down the Mongo server (in particular 100% ...
1
vote
0answers
256 views

Intel cpu hyperthreading on or off for ibm db2? [closed]

Has anyone ever done any database performance comparisons with hyper-threading enabled vs disabled? We are running ibm db2 and I'm curious if anyone has an recommendations for enabling hyper-threading ...
1
vote
1answer
197 views

How does MySQL 5.5 and InnoDB on Linux use RAM?

Does MySQL 5.5 InnoDB keep indexes in memory and tables on disk? Does it ever do it's own in-memory caching of part or whole tables? Or does it completely rely on the OS page cache (I'm guessing that ...
0
votes
2answers
96 views

Server configurations for hosting MySQL database

I have a web application which uses a MySQL database hosted on a virtual server. I've been using this server when I started the application and when the database was really small. Now it has grown and ...
5
votes
5answers
1k 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 ...
5
votes
1answer
1k 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 ...
0
votes
1answer
622 views

Looking for a bottleneck in MySQL server

I have two Ubuntu servers with very similar, if not identical, configuration: both have 16 cores (4 E5540 Xeons), 16GB RAM, HP Smart Array P212 controllers with 2 HDDs in RAID1. I/O scheduler used is ...
3
votes
9answers
677 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 ...