Jonathan Tapicer wrote: > Hi, > > I don't say that reading the whole file into memory is the best > option, I just say that your approach goes to the disk twice, if you > have a 100MB file, you are reading 200MB from disk (unless there are > some pages cached in physical memory, but you never can know, in the > best case all the pages will be cached and you will only read 100MB > from disk); and mine, if you have 100MB or more physical memory > (available for the script) will only go once. Of course, if you have > low physical memory, in the worst case you will end up reading 200MB > from disk, because all the pages will go to the pagefile. > > So, both approaches have a worst case of reading approximately two > times the file size from disk and a best case of reading it > approximately only once from disk, and since you never know the actual > conditions of the memory, you can't say which approach is better > without additional information. > > In the general case, I think that your approach is better for large > files and mine for small files, with the size barrier depending on the > memory set up and current conditions at the time the script runs. > > This discussion went in a different direction considering the initial > question of Alain, but this could always be useful for someone. > > Jonathan > > On Thu, Jun 25, 2009 at 5:37 AM, Richard Heyes<richard@xxxxxxx> wrote: >> Hi, >> >>> Well, you are reading the whole file there (and throwing the data you >>> read not assigning the fgets result to anything), and then to store it >>> in the database you need to read it again, so you read the file twice. >>> It will probably better to store the data you read the first time in >>> an array and then store it in the database, that way you read it only >>> once. >> No, it's not. If the file is large then you could end up reading megs >> into memory. If physical memory is low then the pagefile will come >> into play and you'll get a lot of disk accesses. Reading 1 line at a >> time is far more efficient and with larger files will be faster. >> >> -- >> Richard Heyes >> HTML5 graphing: RGraph (www.rgraph.net - updated 20th June) >> PHP mail: RMail (www.phpguru.org/rmail) >> PHP datagrid: RGrid (www.phpguru.org/rgrid) >> PHP Template: RTemplate (www.phpguru.org/rtemplate) >> PHP SMTP: http://www.phpguru.org/smtp >> Stuart is still the winner. -- Thanks! -Shawn http://www.spidean.com -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
