Re: General Mysql Connect

On Wed, 2008-10-29 at 19:49 -0500, Micah Gersten wrote: > Ashley Sheridan wrote: > > On Wed, 2008-10-29 at 19:43 -0500, Micah Gersten wrote: > > > >> Ashley Sheridan wrote: > >> > >>> On Wed, 2008-10-29 at 19:25 -0500, Micah Gersten wrote: > >>> > >>> > >>>> Ashley Sheridan wrote: > >>>> > >>>> > >>>>> On Thu, 2008-10-30 at 08:55 +1100, Chris wrote: > >>>>> > >>>>> > >>>>> > >>>>>> Waynn Lue wrote: > >>>>>> > >>>>>> > >>>>>> > >>>>>>> I sent an email to the mysql list, but it reminded me of a > >>>>>>> question I had > >>>>>>> for people structuring their PHP code. What's the general > >>>>>>> way that people > >>>>>>> structure their connections? Right now, I spawn off two > >>>>>>> mysql_connect calls > >>>>>>> at the top of the file that includes my database calls, using > >>>>>>> "true" for the > >>>>>>> fourth parameters, so as to create two new connections. Then I > >>>>>>> use those > >>>>>>> two connections for two different databases I have to query from. > >>>>>>> > >>>>>>> Is it better just to use mysql_select_db within the query function > >>>>>>> every > >>>>>>> time for the same connection? Should I use mysql_connect every > >>>>>>> time without > >>>>>>> using "true", so as to re-use connections. Should I be > >>>>>>> using pconnect > >>>>>>> instead? > >>>>>>> > >>>>>>> I spent some time looking for answers to these questions, but am > >>>>>>> getting > >>>>>>> conflicting answers. Some people think relying on the re-use of > >>>>>>> these > >>>>>>> functions is good, some think that explicit management is better. > >>>>>>> In > >>>>>>> general, how have people on the list found them? For example, is > >>>>>>> having > >>>>>>> constant mysql_select_db calls a problem? > >>>>>>> > >>>>>>> > >>>>>> Are they connecting as the same user and on the same server? Then you > >>>>>> can replace with a mysql_select_db call. > >>>>>> > >>>>>> If they aren't both of those, you have no choice. > >>>>>> > >>>>>> No idea if it'll make much of a difference (performance wise etc) > >>>>>> but > >>>>>> I'd leave it as two connections. > >>>>>> > >>>>>> > >>>>>> > >>>>> How difficult would it be to converge the 2 databases into one? This > >>>>> would obviously use less memory (not sure exactly how big the footprint > >>>>> of each connection is though) and will slightly speed up page display > >>>>> time (as you only have to wait for one connection to be made rather than > >>>>> two) > >>>>> > >>>>> > >>>>> Ash > >>>>> www.ashleysheridan.co.uk > >>>>> > >>>>> > >>>>> > >>>>> > >>>> Generally you want separation of data. MySQL doesn't have a problem > >>>> accessing another DB on the same server with the same connection. Also, > >>>> how would database convergence use less memory? > >>>> > >>>> . > >>>> Thank you, > >>>> > >>>> > >>> For arguments sake, open 1000 database connections, all to different > >>> databases. Now tell me that each connection doesn't have a footprint. At > >>> the end of the day, whist it may seem fine for a script to have 2 > >>> connections open, the least open the better. Imagine 100 users > >>> simultaneously accessing a page that opens 10 connections. Suddenly you > >>> have 200 connections open, not a great idea. If you could amalgamate the > >>> db's, you'd have half as many connections open. > >>> > >>> If you're still having trouble understanding why having two database > >>> connections open is bad (regardless of whether they are on the same > >>> server or not) the I think web development is the wrong career for you. > >>> > >>> > >>> Ash > >>> www.ashleysheridan.co.uk > >>> > >>> > >> The answer in your case is not to combine the DBs necessarily, but > >> consolidate the connections used. Like I said, you can use 2 MySQL DBs > >> on the same connection in PHP. There's no reason to sacrifice > >> separation of data. > >> > >> Thank you, > >> Micah Gersten > >> > > I'm sure if you look at the OP codes on your suggestion, you'd still use > > the same memory as having two separate connections open, unless you > > closed one first. Thing is, opening and closing database connections has > > its own overheads. > > > > > > Ash > > www.ashleysheridan.co.uk > > > > How is using one connection the same as having 2 open? You just change > databases if you want to, or use the fully qualified table name > (database.table) in your query. What extra overhead is there in that? > > Thank you, > Micah Gersten > onShore Networks > Internal Developer > http://www.onshore.com > > > Having one connection open at a time has only the overhead of the opening and closing of connections. As far as I know, you can't have two databases open on one connection, but please correct me if I am wrong. Ash www.ashleysheridan.co.uk