Barry Brevik <> wrote: > I am now writing some database extraction utilities at the company I > work for, using Perl on Windows 2000/XP. There are several static > tables I download via ODBC that I perform lookups into... An ideal > application for a hash. > > After the 5th table, I started to worry about how much memory this > was using, so I checked the combined size of these hashes, and it > came to about 64KB. This is without factoring-in the hash overhead. > The app runs well right now, but I'm concerned about breakage going > forward. > > Since this is used in-house, I can guarantee that the app will always > run on a machine with at least 2 GB of RAM and a 4 GB swap file. The > user might also be running a couple of Office apps, but that would be > all. > > Granted that the answer to this question includes *many* variables I > have not addressed, is there still some sort of guideline I can use > to determine how much memory tied up in hashes is "too much"?
If you want to get a better picture of how much memory your hashes are using, then something like Devel::Size might help, but I think you will need considerably more than 64kb to give you any problems. Of course if you are worried about the size of your hashes, it is generally recommended to store them on disk, using Tie and the DB modules, but you pay a penalty in access times, ... ... or alternatively store your hashes in a database! > Also, > if I reinitialize an existing hash to (), will that return the memory > to Windows? Perl may well return some freed memory to the OS in some circumstances, but don't rely on it. HTH -- Brian Raven ========================================= Atos Euronext Market Solutions Disclaimer ========================================= The information contained in this e-mail is confidential and solely for the intended addressee(s). Unauthorised reproduction, disclosure, modification, and/or distribution of this email may be unlawful. If you have received this email in error, please notify the sender immediately and delete it from your system. The views expressed in this message do not necessarily reflect those of Atos Euronext Market Solutions. Atos Euronext Market Solutions Limited - Registered in England & Wales with registration no. 3962327. Registered office address at 25 Bank Street London E14 5NQ United Kingdom. Atos Euronext Market Solutions SAS - Registered in France with registration no. 425 100 294. Registered office address at 6/8 Boulevard Haussmann 75009 Paris France. L'information contenue dans cet e-mail est confidentielle et uniquement destinee a la (aux) personnes a laquelle (auxquelle(s)) elle est adressee. Toute copie, publication ou diffusion de cet email est interdite. Si cet e-mail vous parvient par erreur, nous vous prions de bien vouloir prevenir l'expediteur immediatement et d'effacer le e-mail et annexes jointes de votre systeme. Le contenu de ce message electronique ne represente pas necessairement la position ou le point de vue d'Atos Euronext Market Solutions. Atos Euronext Market Solutions Limited Société de droit anglais, enregistrée au Royaume Uni sous le numéro 3962327, dont le siège social se situe 25 Bank Street E14 5NQ Londres Royaume Uni. Atos Euronext Market Solutions SAS, société par actions simplifiée, enregistré au registre dui commerce et des sociétés sous le numéro 425 100 294 RCS Paris et dont le siège social se situe 6/8 Boulevard Haussmann 75009 Paris France. ========================================= _______________________________________________ ActivePerl mailing list [email protected] To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs
