Results 1 to 2 of 2

Thread: Does multiple MySQL DB-connections increase performance?

  1. #1
    Join Date
    Mar 2010
    Posts
    77
    Thanks
    17
    Thanked 1 Time in 1 Post
    Qt products
    Qt4
    Platforms
    Unix/X11 Windows

    Default Does multiple MySQL DB-connections increase performance?

    Hello!
    I guess this is more of a MySQL question but since it involves how to interface to a DB-server from C++/Qt I would say it is appropriate to post here. =)

    I'm currently developing an application that is connecting to a MySQL database server run on a multi-core PC.
    I don't know much about MySQL but I'm starting to get hang of the basics.

    I'm designing a class (derived from QThread) that is run on the client computer and I'm now thinking about possible differences in performance if I create multiple instances (and thereby connections to the server) of this class for each client.

    I have no idea on what MySQL Servers policies on threading looks like. So I thought: IF the server only allows for one thread to start for each connection to it I will probably have a better performance if I have two (or more) connections.
    The server will most likely never have more than say 10 clients connecting.

    The reasoning is that the small 'simple-few-rows-SELECTs' should still be snappy even though a complex query (that might take a second or two) ordered by the same client is being executed at the same time.

    This multi-connection approach feels kind of wrong but I still wanted to ask.
    Your thoughts?

    Thanks!
    /Tottish

  2. #2
    Join Date
    Mar 2010
    Location
    Capelle aan den IJssel, Netherlands
    Posts
    24
    Thanks
    1
    Thanked 1 Time in 1 Post
    Qt products
    Qt4 Qt/Embedded
    Platforms
    Unix/X11 Windows Symbian S60

    Default Re: Does multiple MySQL DB-connections increase performance?

    Hmm, I guess when you create a connection, the database creates a session for it.
    Within that session, for as far I know, you can only execute one query at a time. A query is also a blocking thing, I don't see how else the database server can safely handle your transaction.

    I thought there is something like connection pooling and I think Qt uses that, but that is for not opening and closing the connection all the time, but rather reuse the same connection to the database that is already open (hence, saving you the overhead of opening and closing the connection again).

    So for that matter, if you have a time critical check (the simple-few-rows-SELECT's), that cannot wait a few seconds for complex queries to be executed, you even MUST use multiple connections.
    I do not think this is a performance issue though, especially when you are talking about 10 connections max. After all, they are "just" TCP/IP connections which exchange some data.
    Just the database has to do some stuff in parallel, but hey, that is what it was designed for, isn't it

    So in my opinion, multiple connections all the way

Similar Threads

  1. Distributing software with MySQL connections across different MS OS:es
    By Tottish in forum Installation and Deployment
    Replies: 1
    Last Post: 15th December 2010, 10:39
  2. Multiple connections to MySQL database
    By ShamusVW in forum Newbie
    Replies: 4
    Last Post: 11th August 2010, 07:28
  3. Multiple connections with QTcpSockets
    By DrDonut in forum Qt Programming
    Replies: 1
    Last Post: 11th September 2009, 11:58
  4. Increase QPainter performance
    By travelan in forum Qt Programming
    Replies: 3
    Last Post: 3rd July 2009, 12:52
  5. Qt on X11 with multiple display connections?
    By grenoble in forum Qt Programming
    Replies: 1
    Last Post: 25th February 2008, 13:44

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Digia, Qt and their respective logos are trademarks of Digia Plc in Finland and/or other countries worldwide.