# Saving to the DB uses a lot of RAM? **URL:** \ **Category:** Rails\ **Created:** [January 30, 2010, 2:12am UTC](https://www.ruby-forum.com/t/saving-to-the-db-uses-a-lot-of-ram/182566 "2010-01-30T02:12:19Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![PierreW](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/da6949/32.png) [@PierreW](https://www.ruby-forum.com/u/PierreW)\ **Post date:** [January 30, 2010, 2:12am UTC](https://www.ruby-forum.com/t/saving-to-the-db-uses-a-lot-of-ram/182566/1 "2010-01-30T02:12:19Z")
Hi guys, I must be missing something obvious… array\_of\_stuff = [contains a lot of fairly small AR objects] # RAM at 30MB array\_of\_stuff.each do |foo| foo.save end array\_of\_stuff = nil # RAM at 60+MB The iteration itself takes 30+MB of RAM (I measure with "memory\_usage from #{pcaller} at l.#{pline}: "+`ps -o rss= -p #{$$}`.to\_i.to\_s). I don’t get it. Why is this using so much memory? Thanks a lot, Pierre ---
**Author:** ![PierreW](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/da6949/32.png) [@PierreW](https://www.ruby-forum.com/u/PierreW)\ **Post date:** [January 30, 2010, 2:37pm UTC](https://www.ruby-forum.com/t/saving-to-the-db-uses-a-lot-of-ram/182566/2 "2010-01-30T14:37:15Z")
PierreW wrote: > Hi guys, > > I must be missing something obvious… > > array\_of\_stuff = [contains a lot of fairly small AR objects] > > # RAM at 30MB > > array\_of\_stuff.each do |foo| > foo.save > end > array\_of\_stuff = nil This is terrible! You should never have a DB query inside a loop. Instead, generate one query to insert all the records. The ar-extensions plugin can help with that. > # RAM at 60+MB > > The iteration itself takes 30+MB of RAM (I measure with "memory\_usage > from #{pcaller} at l.#{pline}: "+`ps -o rss= -p #{$$}`.to\_i.to\_s). > > I don’t get it. Why is this using so much memory? > > Thanks a lot, > Pierre ## Best, Marnen Laibow-Koser [http://www.marnen.org](http://www.marnen.org) removed\_email\_address@domain.invalid ---
**Author:** ![PierreW](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/da6949/32.png) [@PierreW](https://www.ruby-forum.com/u/PierreW)\ **Post date:** [February 1, 2010, 4:43am UTC](https://www.ruby-forum.com/t/saving-to-the-db-uses-a-lot-of-ram/182566/3 "2010-02-01T04:43:05Z")
I am sorry but I don’t have an answer about the RAM question. However I would like to answer Marnen’s comment. While I agree that letting the DB do the work for mass record processing should be the best and most efficient way to go by reading the OP one cannot assume that is the way things are in this case. The array used by the OP could very well contain tons of different types of objects, used for very different purposes and not necessarily related to each other. Pierre never gave any indication it was one way or the other. ---
**Author:** ![PierreW](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/da6949/32.png) [@PierreW](https://www.ruby-forum.com/u/PierreW)\ **Post date:** [February 1, 2010, 1:53pm UTC](https://www.ruby-forum.com/t/saving-to-the-db-uses-a-lot-of-ram/182566/4 "2010-02-01T13:53:43Z")
pepe wrote: > I am sorry but I don’t have an answer about the RAM question. However > I would like to answer Marnen�s comment. While I agree that letting > the DB do the work for mass record processing should be the best and > most efficient way to go by reading the OP one cannot assume that is > the way things are in this case. No, but it’s likely. > The array used by the OP could very > well contain tons of different types of objects, used for very > different purposes and not necessarily related to each other. Then for the purpose of saving, they should be separated out by type. Queries don’t go in loops. Period. > Pierre > never gave any indication it was one way or the other. True. So why “correct” me with an unlikely exception to the general principle? ## Best, Marnen Laibow-Koser [http://www.marnen.org](http://www.marnen.org) removed\_email\_address@domain.invalid ---
**Author:** ![PierreW](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/da6949/32.png) [@PierreW](https://www.ruby-forum.com/u/PierreW)\ **Post date:** [February 1, 2010, 11:28pm UTC](https://www.ruby-forum.com/t/saving-to-the-db-uses-a-lot-of-ram/182566/5 "2010-02-01T23:28:18Z")
On Feb 1, 7:53 am, Marnen Laibow-Koser [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > pepe wrote: > > > I am sorry but I don’t have an answer about the RAM question. However > > I would like to answer Marnen s comment. While I agree that letting > > the DB do the work for mass record processing should be the best and > > most efficient way to go by reading the OP one cannot assume that is > > the way things are in this case. > > No, but it’s likely. Anything is likely. > > The array used by the OP could very > > well contain tons of different types of objects, used for very > > different purposes and not necessarily related to each other. > > Then for the purpose of saving, they should be separated out by type. > Queries don’t go in loops. Period. Says who? The point I was making is that it would depend on the situation and the solution the OP is trying to give to his particular problem. > > Pierre > > never gave any indication it was one way or the other. > > True. So why “correct” me with an unlikely exception to the general > principle? I wasn’t trying to “correct” you. I was trying to offer a different point of view and have an open mind. Cheers. ---
**Author:** ![PierreW](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/da6949/32.png) [@PierreW](https://www.ruby-forum.com/u/PierreW)\ **Post date:** [February 2, 2010, 12:03am UTC](https://www.ruby-forum.com/t/saving-to-the-db-uses-a-lot-of-ram/182566/6 "2010-02-02T00:03:51Z")
pepe wrote: > On Feb 1, 7:53�am, Marnen Laibow-Koser [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > pepe wrote: > > > > > I am sorry but I don’t have an answer about the RAM question. However > > > I would like to answer Marnen s comment. While I agree that letting > > > the DB do the work for mass record processing should be the best and > > > most efficient way to go by reading the OP one cannot assume that is > > > the way things are in this case. > > > > No, but it’s likely. > > Anything is likely. Anything is _possible_…but it’s…er…unusual to be saving an array of unrelated objects. > > > The array used by the OP could very > > > well contain tons of different types of objects, used for very > > > different purposes and not necessarily related to each other. > > > > Then for the purpose of saving, they should be separated out by type. > > Queries don’t go in loops. �Period. > > Says who? Anyone who understands how to use databases efficiently end effectively. > The point I was making is that it would depend on the > situation and the solution the OP is trying to give to his particular > problem. > > > > Pierre > > > never gave any indication it was one way or the other. > > > > True. �So why “correct” me with an unlikely exception to the general > > principle? > > I wasn’t trying to “correct” you. Yes, I realized that after I posted. > I was trying to offer a different > point of view and have an open mind. OK, but in this case I don’t think it was relevant. > Cheers. Best, – Marnen Laibow-Koser [http://www.marnen.org](http://www.marnen.org) removed\_email\_address@domain.invalid ---
**Author:** ![PierreW](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/da6949/32.png) [@PierreW](https://www.ruby-forum.com/u/PierreW)\ **Post date:** [February 1, 2010, 5:14am UTC](https://www.ruby-forum.com/t/saving-to-the-db-uses-a-lot-of-ram/182566/7 "2010-02-01T05:14:07Z")
On Fri, Jan 29, 2010 at 8:10 PM, PierreW [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > end > Pierre Pierre, you might be interested in the following thread within this mailing list because it covered a similar topic: “activerecord 2.3.5’s create & find slower than activerecord 2.1.2” Good luck, -Conrad